Pigments, Paints & Dyes

Today volumes and varieties of premixed paints are easily purchased in stores, but this has not always been the case.  Our predecessors just a generation or two prior had to make their own paints, whether intended for a house or barn, or for art.  Right up into the 1930’s or 40’s in construction, paint was made on the job-site and the contractors had to apprentice for many years before becoming competent and considered qualified to make quality paint.  The accomplished fine art painters or masters of yesteryear were akin to alchemist and their materials were varied.  Simultaneously however, many unskilled but ambitious artist may have watched their creations crack, change color or literally slide away from the canvas.  While premixed oil paints were being sold in little squeezable tubes by the 1860s, the knowledgeable and adept artist still depended upon the ability to grind his own pigments and mix his own paints.  With a little know-how it is actually easy to make a decent paint, in most any color.  Cro-Magnon cavemen mixed metallic oxides with tallow or clay to make paints that are still clinging to some stone walls today after thirty six thousand years have passed.  Our repertoire of pigments and binders has grown since then.  An attempt will be made here to organize and explain some basic binders, pigments and dyestuff.

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* Visiting cave paintings briefly;

   The elements are in a constant state of flux. The erosion and the degradation caused by mother nature is very rough. Any artistic medium must be robust to survive even a decade.  These cave paintings and sculptures of the long since past have only survived because they were sheltered and protected.  Most of the cave art in Europe created during the last ice age has probably been destroyed as a result of successive human activity.  Continued human habitation within a cave would lead to increased smoke and soot. Excessive carbon dioxide from both fire and human breathing might have encouraged detrimental lichen and mold growth upon the cave’s interior. Those caves today that still possess clear aurignacian or gravettian period cave art, do so because they became sealed off somehow from the outside atmosphere. The early humans that painted the pictures seldom if ever lived in those particular caves where cave art has survived. Multiple painters over a wide span of time created the artworks in these caves. Three of the most prominent caves in Europe still possessing pristine parietal paintings were just recently (analogous to their age) re-discovered. The Cave of Altamira in the north of Spain was found in 1879. The Lascaux Cave in the southern half of France was found shortly after the German occupation of France in 1940.  The Chauvet-Pont-d’Arc Cave of south France was re-discovered only in 1994.  These have all been sealed off again, as protection from outside atmosphere and from contamination by human tourism. Pablo Picasso who in 1948 visited the Lascaux cave before it was closed to the public, praised the prehistoric art; stating that man had learned nothing new since then.

The principle colored pigments used in the Lascaux cave for instance were the iron oxides or hydroxides known as hematite, goethite and ocher. Black pigments were provided by magnesium oxide and charcoal.  European cave paintings, engravings and sculptures are grouped together or classified as “Franco-Cantabrian” art because of their geographical concentration inland, both east and south of the Bay of Biscay.

Paint

It usually takes only two or three items to create a paint; a binder, a pigment and a filler.  Any particular paint is classified by its type of binder that in turn is reduce-able by a solvent.  Binders hold pigments and fillers together and onto surfaces.  Pigments can come from plants or animals, from dirt or rock minerals or they can be chemically synthetic.  Fillers if present might influence the opacity of a paint but mainly are added to expand or extend a paint’s bulk and coverage without affecting its color.  When comparing an oil, a tempera or an acrylic version of paint; these might all share the same exact pigment but differ only in having incompatible binders.  The chemical sophistication of modern day automobile paint mixtures are perhaps no more confusing, nor are more complex than some of the mixtures used on the pallets of the late Renaissance painters.  A host of toxic materials like arsenic, chromium, lead, radium and uranium were once commonly used in paints because they were effective.  Commercial house, furniture and spray paints today are usually less convoluted than the compounds once found on an artist’s pallet.  There, one may have found rarefied distillations of tree sap, rabbit skin glue, raw egg yoke, crushed up bug juice or perhaps even pulverized mummy remains.

Binders

The binder dries to form a film that then determines the texture, flexibility and permanency of paint.  Children like to taste things.  Naturally they put things in their mouths as they explore the world about them.  Many effective, once popular binders (or pigments as well) have been removed from commercial paints for this very reason.  Child safe paints, most of which can be produced at home anyway would include binders composed of glutinous grain starch (from rice, rye, wheat flours, etc), soap, shampoo, gum Arabic, shaving cream, gelatin, clay, honey and maple syrup.  Example paint binders not fit for consumption would include things like tallow, linseed and tung oil, shellac, raw egg yoke, beeswax, water glass (sodium silicate), acrylic, epoxy resin, alkyd resins and nitrocellulose lacquer.  A solvent is usually needed to thin out paint, to clean equipment or to clean up spills.  Some example solvents would include “the universal solvent” (water), alcohol, ether, essential oils, turpentines from plants, mineral spirits from coal tar, naphthas like benzene, toluene and xylene from petroleum.

   Casein is an ancient paint binder and glue, one regularly used by the Egyptians.  Made from milk protein, casein makes an excellent woodworking glue and it can also create a fine water soluble paint that dries quickly.  Used in ancient “tempera” (or preferably “distemper”) paints, casein paint was actually the favored medium for many modern illustrators right up into the 1960s. Then acrylic paints generally replaced casein bound paints in popularity, because casein paint if unused would tend to spoil after a few days.  For centuries moisture resistant casein glue has been used in laminated wood and furniture.  Casein immersed in formaldehyde created one of the earliest synthetic plastics.  Casein glue is milk protein (itself called “casein” which comprises about 3% of milk) dissolved in an aqueous alkaline solvent.  Making a simple casein glue or binder involves little more than causing milk to curdle by introducing vinegar perhaps, pressing out the excess whey and then neutralizing the acid with an alkali like sodium carbonate (baking soda).  Non-fat milk makes better glue than whole milk would because fat molecules prevent the casein from properly polymerizing.  Low-fat cottage cheese is already converted to curds so it works faster than milk.  The type of alkali used, substantially influences the properties of the final glue or binder.  Alkali s like borax (sodium tetraborate), ammonium carbonate (originally acquired by the destructive distillation of red deer antlers or “hartshorn”), potash (potassium carbonate) and lime ( either “quicklime” (calcium oxide) or “slacked lime” (calcium hydroxide)) have all been used to engineer casein glue and paint binders.  Quick lime or slacked lime works well for casein paints which need to be alkali resistant for applications like stuccoed walls or fences.  The “fresco” below was done by a Minoan painter sometime between 1600 and 1500 BC.

Fresco / https://commons.wikimedia.org/wiki/File:Fresco_of_a_fisherman,_Akrotiri,_Greece.jpg

Minoan Bronze Age fresco

When you mix cellulose with lye and heat it you get a mild but useful glue known as methyl cellulose.  Methyl cellulose can be used as a lubricant, an emulsifier, gel, as an additive for food, shampoo and toothpaste, as an additive to mortars and gypsum related construction materials and as a binder for medications, wallpaper paste, liquid paints and in dry pastel crayons.

  Hide glue and the gelatin we often eat in some processed foods are both made from an animal protein known as collagen.  It is soluble only in water and therefore is insoluble in oils, alcohol or other organic solvents.  Hide glue is typically made from animal hides and perhaps hooves, tendons and bones (that are cured in a lime slurry for a couple months before being boiled in water and then reduced).  The hide liquor can be further processed by drying and then by crushing it into chips, flakes or powders that are intended to be re-constituted with water at a later date.  A little heat is necessary so that the re-hydrated binder can be converted from a gel to a liquid before it is applied.  It does not store well in wet form and unused portions will mold.  Hide glue is the preferred glue used for stringed instruments like violins and cellos.  The wood in these delicate instruments is under stress and will expand or contract according to humidity, temperature or external pressure.  Hide glue when dry is appropriately flexible and weaker that the wood it is bonded to.  If a violin is stressed to the point of breakage then the glue bond should break before the wood does. Ideally the instrument can be easily fixed.  This is a handy feature considering that some 300 year old Guarneri del Jesu and Antonio Stradivari instruments can fetch more than $16 million at auction.

Usually animal skin glue is used to prepare, pre-coat or seal a ‘support’.  In the world of ‘fine art’ a support is the substructure of a painting – like wood, paper or stretched canvas.  The ground is the foundation, that first layer of primer painted upon the support.  The size is necessary only for fabric supports and it is painted on above the ground to plug up and and seal the canvas from the penetration of oils. Linen and cotton will prematurely rot without a size layer.  Many sizes have been used but rabbit skin glue was the most conventional ‘size’ used for oil painting and was supposed to be a bit stronger, more elastic and slower to gel than other hide glues.  If used for a ‘size’ then rabbit skin glue was usually mixed with gypsum, marble dust and titanium dioxide to create traditional white ‘gesso‘ sizing. Since climatic changes in temperature and humidity can cause old oil paintings to crack, poly vinyl acetate has become the preferred binder in contemporary ‘gesso’ or ‘size’ for fabric supports.  Fish glue or “isinglass” (made from air bladders, boiled skins and fish bones) was used by the ancient Egyptians and was later prevalent in the parchment manuscripts illustrated and gilded by medieval monks.  Fish glue was one of the more successful fixatives used in pastels, where pulverized pigment, white chalk and binder were commonly rolled up into a cylinder before they were dried.  Today isinglass is still useful as a “fining agent” for the clarification of some wines and beers.

* Tempera, Distemper, Encaustic and Fresco painting:

   Casein and hide glue have been used since antiquity to bind up and apply pulverized pigments.  The term “tempera” has often been used to casually imply several mediums (like egg, honey, plant gums milk casein and hide glue) though.  To most artist today “tempera” implies a technique employing only the egg yoke medium, and they might use the new term “distemper” to differentiate and encompass the other binders used in a similar way.  Tempera painting is very old and robust and was very common before “oil paints” became popular in the 15th century.  Some examples of tempera still exist, which were painted almost two thousand years ago.  Egg tempera dries very quickly so usually a bit of wine, vinegar or water is added to extend its period of workability.  Also about 2,000 years old, “encaustic” painting is a technique where pigments are added to melted beeswax.  Metal tools, special brushes and heat are used to spread the pigmented wax around before it solidifies.  “Fresco” (meaning fresh) is a technique where pigment is applied onto wet plaster.  The hue is drawn into and becomes part of the wet plaster itself after it is applied to ceilings, walls or murals. “Fresco-secco” on the other hand describes painting upon dried plaster.  The famous ceiling of the Sistine Chapel taken as a whole, is an enormous fresco painting done by Michelangelo about 500 years ago.

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  Silicate mineral paints are made from mineral pigments and soluble glass as the binder. “Water glass” (sodium or potassium silicate, liquid glass or Keimfarben) is made by melting silicon dioxide (silica / quartz sand) and soda ash (sodium carbonate) together.  The result is an exterior masonry paint binder or indoor product for mural painting, that is far more resistant to cold and damp and ultraviolet light than traditional lime fresco is.  Keimfarben was popular for a while as a 19th century variation of fresco, and remains useful today as a coverage for concrete and masonry walls.  Other uses for sodium silicate include its use as a paper glue in the manufacture of cardboard, as a tool for water treatment, as a fixative for reactive dyes, as a binder for refractory mixes and as a major component of dry-powder laundry and dishwasher detergents.

Oils

Some of the most important binders of all time are the so-called “drying oils”. These are the foundation of oil paints. When exposed to oxygen these particular oils have the property of polymerizing into the hard films we associate with dry finished, cured paint.  Linseed oil and tung oil are the most significant examples in this category but there are others less frequently used like poppy oil, soybean oil, castor oil, candelnut oil and so on.

  Linseed oil is squeezed from the seeds of the flax plant.  Flax seeds are edible and the fibers from the plant are probably the longest ones to be found in the textile industry.  Linen is the fabric made from flax fibers and both ancient Babylonians and ancient Egyptians cultivated the plant.  Raw linseed oil is edible but it does not dry or oxidize very quickly.  Therefore a quicker to dry “boiled linseed” was realized by experimentation.  In the 19th century additives like lead acetate and zinc sulfate were introduced to raw linseed oil and then heated, to improve the drying performance of the oil.  Today the heavy metal driers (perhaps cobalt & manganese salts) of boiled linseed oil may have changed to ones safer to handle, but boiled linseed is still not safe to eat.

  Tung oil (or Chinese wood oil) usage reaches way back before the Song Dynasty in China. The oil is squeezed from the nuts of a poisonous tree. This oil was or still is used for waterproofing wooden ships & paper umbrellas and for providing light when used as a lamp oil.  Modern day granite and marble counter-tops can be waterproofed and made stain resistant by thinned coats of tung oil.  Tung trees were once imported to the southeastern U.S. and planted as commercial crops.  Since that time the prolific and toxic trees have been classified as unwanted and invasive plants in states like Florida and Mississippi.  There have been incidents where school children on field trips have been poisoned after mistaking tung nuts for chestnuts.

Both linseed and tung oils make superior wood finishes that penetrate deep and rejuvenate cellulose.  Tung oil which is more expensive, may or may not be preferable in some situations because it is less likely to darken wood or to yellow.  Tung oil will eventually harden or polymerize by itself but boiled linseed preforms much faster – making linseed by far the most common drying oil employed in oil paints.

* Linoleum is a superior type of non slip floor covering made with linseed oil, which was invented around 1855 and became very popular by the beginning of the 20th century.  Being more flexible than ceramic tile, it could be applied to wooden floors and not crack under stress.  The thick inlaid linoleum floors were extremely durable but eventually thinner, printed pattern linoleum tile was manufactured.  Still this thinner linoleum flooring should be preferable to the cheap polyvinyl chloride (PVC) floor covering so popular today.  Simple enough to make at a remote construction site, linoleum fabrication usually began with a burlap or canvas backing.  The obligatory ingredients for linoleum tile were fine sawdust (or wood flour) linseed oil and some color pigment. Occasionally pine rosin and calcium carbonate (crushed limestone / as an extender) was thrown into the mix.  In fact, calcium carbonate (occasionally called whiting) is often used to extend or to fill in many types of paint, plastics and thermosetting resins.

Gums

Gums, resins, turpentines and essential oils come from plants and whether mixed to together or used separately they still have been used as paint binders for hundreds or even thousands of years. “Gums” for example result from “gummosis” which is a condition of sap flowing from a wound or disease in a bush or tree.  Gums are colloidal (a mixture in solution that does not settle) and are soluble in water while simultaneously being insoluble in alcohol or ether.  Resins may occur either alone or alongside gums and essential oils but they are conversely – insoluble in water but are dissolved by alcohol and ether.  Then there is a large group of harder resins called “copals”.   Amber which is a petrified tree sap, falls into this category.  Oleoresins are solutions of resin or wax mixed with essential oils and fatty oils.  Turpentine is an oleoresin collected and distilled usually from pine tree sap.  Balsams are like oleoresins but are generally more aromatic and occur naturally.  Essential oils are the fragrant, volatile compounds from plants, usually extracted by distillation.

Confusingly gum arabic and Arabic gum are two very separate but famous and important tree saps.  The natural gum and polysaccharide “gum arabic” comes from the hardened sap of select acacia trees.  “Arabic gum” (or mastic) on the other hand is resin collected from a totally unrelated dioecious shrub of the Pistacia (pistachio) family.  Both resins were known in antiquity, both were used in foods, as medicines, as paint binders and both still share great value as precious commodities.  A major portion of the world’s supply of gum Arabic comes from Sudan while most mastic comes from a small island, farther northwards from the equator.

Gum arabic is composed of saccharides and glycoproteins which give it the utility of a glue and paint binder and make it edible by humans.  Thousands of years ago the Egyptian Pharaohs were being mummified with the help of gum Arabic.  It is the same useful glue used on the back of a postage stamp, which is licked before sticking to an envelope.  It is used in cosmetics, shoe polish, candies and chocolates, to treat upset stomachs or to stop both diarrhea or constipation.  Gum arabic is indispensable in traditional lithography, paper and textile printing, where it controls viscosity in inks or repels ink from background areas on the plate of an offset press.  “A dab of gum arabic makes newspaper ink more cohesive and permanent”.   In medicine, gum arabic is used as an emulsifier to keep ingredients from separating or as a demulcent to temporarily defend the mouth, lips, tongue, eyes or nose from irritation.  It is used in glazes and paints, particularly in watercolors where it binds pigments to paper.  Gum arabic literally holds the multi-billion dollar soft drink industry together.  Without its ability as an emulsifier, the sugar in a ‘soda pop’ would crystallize and settle to the bottom of its container.  The economic importance of this tree sap has been influential enough to sway national policy.

Mastic or ‘Arabic gum’ was once worth its weight in gold.  It has long been collected from the sap of the Pistacia lentiscus shrub which is mostly cultivated on the Greek island of Chios.  Once dried in the sun the resin could be used as a chewing gum.  The English word “masticate” stems from an original Greek verb for chewing.  Mastic has antibacterial and anti-fungal properties that may counteract gingivitis and tooth decay.  Mastic also contains antioxidants and has traditional been used in medicine.  Just like the gum collected from Sudanese acacia trees, mastic is used to make cosmetics, incense, perfumes, soaps and lotions.  Transparent varnishes made with mastic were once very useful in preserving photographic negatives.

Resins

In the English language the term “resin” it too vague.  A resin usually denotes a highly viscous organic residue and a residue that often solidifies after contact with air.  Within the plant a resin might control water loss or act as an antiseptic. “Oleoresin” is a broad term for compounds collectively containing resins and oils (like turpentine).  At least two different types of oil are distinguished: fatty oils (containing fatty acid chains, lipids, triglycerides and such) and essential oils – which contain volatile aromatic compounds.  A “balsam” isn’t distilled but is an aromatic oleoresin that occurs naturally.  “Copal” was originally a semi hard tree sap used as incense by the natives of Central America, now it is a catchall phrase for similar resins that make good hard elastic varnishes.  Copals can be dissolved by oleoresins, by essential oils or by acetone; but to do so sometimes requires the application of heat.  Amber is a rock, a fossilized resin and the hardest copal.  Rosin is a resin usually collected from pine trees.  Rosin is what is left over after turpentine has been cooked and separated from pine tree sap.  After destructive distillation the leftover solid is ground up into a powder.   Rosin is used in adhesives, soaps, soldering flux, optical lens polishing compound, etching plates in printmaking and in oil paints and tempera emulsions of fine art.  It sees employment as a traction or friction enhancer used by rock climbers, weight lifters, bull riders, gymnast, ballet dancers, violinist and cellist alike.   There are many other plant gums or resins used as binders or glazes in paints.

Also found or even predominant in modern paints are thermosetting and thermoplastic resins.  A “thermoset” or thermosetting polymer is at first soft or liquid, malleable or mold-able before it is irreversibly cured or “set”.  Once hardened, heat cannot be used to change a thermoset’s shape.  Examples of thermosetting resin include Bakelite, epoxy resin, vulcanized rubber, polyurethanes and polyester resin and silicone (the rubber like adhesive and sealant, not the chemical element silicon).  Thermoplastic resins on the other hand are often formed to shapes by injection molding or extrusion molding, but once cooled are still quite modifiable in shape by the reintroduction of heat.  Example thermoplastics include acrylic, nylon, Teflon, polycarbonate, polyethylene, polypropylene, polyvinyl chloride and polystyrene resins.

*  Distillation is used to divide mixtures into separate components.  Destructive distillation (pyrolysis) uses heat to drive off valuable liquids and “volatiles” from organic material.  The organic material’s original form is lost, its molecules cracked, reduced or rearranged into new compounds.  Charcoal, methanol, tar and turpentine are gained by the destructive distillation of wood. Coal gas, coal tar, ammonia and coke are gained by the pyrolysis of coal.  Dry distillation is a case where gas is driven off from a heated solid and is then condensed and collected.  Mineral sulfates treated this way resulted in sulfuric acid when the gasses were absorbed by water.

*  Distillation of crude oil is preformed in an enormous type of still called a fractionating tower or column.  In such a tower the lightest and most volatile “fractions” are the first to rise to the top after the application of heat.  The liquefied petroleum gases such as butane, propane, propylene, butadiene, butylene, isobutylene are the first products to be removed and collected.  Next, in order of their vapor pressures; gasoline, naphtha, kerosene, diesel and fuel oil are separated.  An important phenomena occurring within such a column is “reflux”; an action where condensed vapors (liquid now) fall back down through the column, enriching rising vapors as they drop. 

Steam distillation is useful to extract many organic compounds that might otherwise be destroyed by the high temperatures in a normal retort still or reflux column.  With steam distillation, water vapor lifts vaporized particles from the mass and transports them to the condenser.  In effect the desired products are less damaged because distillation occurs at lower temperature.  Newer and more effective than steam distillation is vacuum distillation which lessens the pressure above the liquid mixture, effectively assisting in the quick evaporation of the lightest volatiles. 

Tiny amounts of essential oils can be extracted from plants by steam distillation or by solvent extraction.  Essential oils are the “essence” of a plant’s fragrance.  They are a concentration of ‘volatile aromatic compounds’ which are in effect only small molecules that change physical state from a liquid to a gas very quickly.  Volatile aromatic compounds move through the air quickly to stimulate the olfactory sensors in our noses.  Essential oils are used in medicines, foods, cosmetics, soaps, cleansers and perfumes.  They are frequently contained within oleoresins.

Lacquer, Shellac and Varnish

In general, lacquers are differentiated from paints by virtue of being more glossy.  The word “lacquer” is derived from the lac insect and a Sanskrit word for the number 100,000.   Millions of these little insects are cultivated for the purpose of secreting a resin that they produce after sucking sap from a tree.  “Shellac” (mostly coming from India) is the filtered and refined bug resin that makes such a useful wood finish and dye for both fabrics and leathers.  There is also a long established lacquer in the orient which is extracted from the Chinese or Japanese “lacquer tree” (Toxicodendron vernicifluum).  This tree sap which turns into a strong safe clear film once dried, actually contains the same poisonous irritant as “poison ivy” and therefore is difficult to work with when wet.

One or two centuries ago westerners tried to imitate the effect of Oriental shellacs and lacquers with what are called “varnishes”.  Omitting synthetic alkyd and polyurethane examples, the best (natural) varnishes came from dissolved copal resins.  Varnishes can be categorized by the type of solvent used.  ‘Spirit varnishes‘ for instance usually use alcohol as the solvent, but occasionally employ naphthas (the lighter liquid petroleum fractions) also.  Certain resins when mixed with these solvents dry fast and hard.  The film may stay clear (does not yellow with age) but the “spirit varnish film” is thin and brittle and not very durable.  ‘Essential oil varnishes‘ will use a heavier solvent like turpentine mixed in with the resin.  While this makes a tougher film than spirit varnish, it may take a long time for the solvent to dry.  Finally the ‘fixed-oil varnish‘ employs a resin mixed in with a “drying oil” like linseed oil. This makes the toughest, thickest most durable film or varnish of all.

   Latex paints might use water soluble acrylic resin, vinyl acrylic or styrene acrylic as binders.  White glue (like Elmer’s ® glue) that children soon become familiar with is actually polyvinyl acetate (PVA or “caparol”) and has the same composition as cheap latex paint.  There is no real latex in ‘latex paint’ actually.  “Latex” should denote natural rubber extracted from a jungle tree, not a synthetic polymer.  Acrylic resin, vinyl acrylic (PVA) and styrene acrylic bound paints are erroneously called latex in the U.S., but their called “emulsion paints” in the UK.  Their chemical composition is complex and far beyond the capability of the average person to replicate.

*  Acrylic resin is about twice as expensive as vinyl or styrenated acrylic.  A typical interior ‘latex paint’ contains about 20% acrylic and 80% vinyl.  Latex paints were unknown before the 1930’s or 40’s.  Prior to that time exterior paints were often made with linseed oil binder and interior paints were often based on milk (casein).  Today’s interior latex should be considered superior in most every way to yesterday’s casein or milk paints.  Exterior latex may exhibit good durability and fade and crack resistance but has not yet completely displaced old fashioned oils.  Here linseed based or alkyd based oil paints are extremely durable themselves and unlike acrylics will often penetrate deeper below the surfaces of wood and rust.  Exterior latex with 100% acrylic binders preform very well though in terms of UV resistance and in alkali resistance when applied to concrete & masonry.  Cheaper, predominately vinyl acrylic latex does well inside where smudges and grime may need to be scrubbed from walls.  Styrenated acrylic latex paint is often used on ceilings; its also good as a concrete or masonry sealer because it resist alkali burn and efflorescence (that situation where salt leaches through to the surface of concrete or another porous material and forms crystals).

   Alkyd paints were invented in the 1920’s, improved upon and used sporadically by some in the 1930’s and were commercialized in the 1940’s.  DuPont produced its first alkyd paints for artist in 1931.  The word “alkyd” (or “alcid”) is derived from the words “alcohol” & “acids”, which are both required to make the polyester.   Alkyds are polyesters manufactured from polyols (alcohols), aromatic acids and organic fatty acids.  Alkyds have become the most common “oil-based” type, premixed paints that are commercially available.  Since alkyds are made from both petroleum and vegetable products they are also reduced or thinned by most petroleum solvents or vegetable oils.

   Epoxy polymers are mixed with complimentary hardeners to produce whats called a thermosetting resin.  A thermoset is at first wet or soft before it becomes hard, insoluble and irreversibly cured.  Thermoplastic polymers on the other hand are pressed or injected into molds using heat.  Epoxy resins are important engineering or structural adhesives but they are more frequently being used as tough paint coatings by industry as well.  The surface paint or a priming undercoat of an automobile may be epoxy resin because of the superior adhesion and corrosion resistance this paint provides for metal.  Many water pipes, rebar (iron bars used to reinforce concrete), appliances like refrigerators, stoves, laundry driers and washers are covered with epoxy powder coat called FBE (Fusion Bonded Epoxy Powder Coatings).  Epoxy coatings are more heat resistant than latex-based or alkyd-based paints but they still deteriorate under UV exposure.  Like both latex and alkyds, epoxy resin was thought up and perfected by chemist rather recently (the 1930s).

  Nitrocellulose lacquer:  Many women paint their fingernails with the same chemical used to make gunpowder.  General Motors began painting automobiles with the lacquer in the 1920’s.  Nitrocellulose (guncotton or collodion or cellulose nitrate) was not the first “high explosive” because “nitrostarch” was discovered or invented about thirteen years before.  The inventions of nirtoglycerin and then dynamite would follow, not precede guncotton.  In 1846 nitrocellulose was apparently discovered or stumbled upon simultaneously by three different chemist working concurrently in separate laboratories.  It was made by saturating plant cellulose (like cotton) in nitric acid.  Nitrocellulose became the main ingredient in smokeless gunpowder and it became a support for photographic film.  It was probably the first plastic, and as a substitute for ivory it was soon molded into piano keys, billiard balls, tool handles and so on.  Nitrocellulose was also used to make the first transparent plastic roll film used for photography and it was used as a binder for tough, glossy automotive paints.

* Before nitrocellulose, nail polish might have been made from a mixture of gum Arabic, beeswax, egg white, gelatin and vegetable dye.

* The most common nail polish remover is acetone but his can be harsh on skin and nails. Sometimes ethyl acetate is preferred and this us usually the original solvent for nail polish itself, anyway.

* Before Henry Ford started making millions of his Model T’s, the other car makers used oil paints to accent their automobiles. As early as 1865 commercial oil paints began to appear that had extended shelf life due to the addition of sodium silicate (see waterglass or Keimfarben above). Based on slow drying linseed or tung oils these other car paints might have taken several weeks to harden. These oil based paints looked good for a year or two until ultraviolet light from the sun began to fade, yellow or dull the color. Ford’s innovation was to develop asphalt-based baked enamels for his cars that were similar to a paint technique called “Japanning”. Japanning is a dark decorative patina or finish acquired by painting a thin layer of bitumen (asphaltum) over an object but allowing some of the original surface to show through. Ford saturated his fenders, hoods and other metal parts with Japan Black (a paint bitumen) suspended in linseed oil and tinned with either mineral spirits or petroleum naphtha. The wooden components used a different paint recipe. Then as Japanned ornaments usually are, the metallic parts were baked in a tunnel oven for about an hour on a separate, slow moving assembly line. At the height of production a new Model T – with paint thoroughly dried – rolled off the floor about every three minutes. Drying time was not the only consideration for Ford, because the black paint job was much cheaper and ultimately more durable than what the competition was producing.

* Pierre DuPont owned stock in General Motors, years before his chemical company developed nitrocellulose paint lacquers. Around 1923 GM hit the automobile market with cars painted in new colorful “Duco paints” (pyroxylin / nitrocellulose based). These paints came in every color of the rainbow and took only minutes to dry. In the 1930’s the first metallic car paints appeared. These used real fish scales at first and eventually graduated to cheaper aluminum flakes. Sunlight resistant clear coat enamels for cars appeared in the 1940’s. The first synthetic polymer / transparent thermoplastic, “acrylic resin” car coats appeared in the 1950’s. These had the advantage of drying much faster than enamel coats. Acrylic lacquers were eventually superseded by what is preferred today, which is usually called a “clear coat finish”. A clear-coat-finish usually consist of a primer, a color coat and a clear, tough, polyurethane topcoat.

Fillers

Fillers are intended to increase and extend the coverage of paint. Fillers are cheap, non-essential components that add bulk and might sometimes influence opacity. Example fillers include: clay, chalk, powdered marble / calcium carbonate, mica, baking soda, plaster of Paris, tile grout, sugar and vinyls like polyvinyl chloride or polyvinyl acetate.

Pigments

Practically any attractively colored earth can be used for homemade pigment.  A good way to process it is to boil a quantity in water for several hours.  Strain out the impurities and larger aggregate and pour off the excess water.  Place the still moist residue in shallow pans and allow to dry.  Grind further in mortar and pestle if possible and sift once more through a finer screen or filter.

Pigments are insoluble color particles that require a binding agent to hold them onto the surface of the material being covered.  The first pigments came from the earth and from inorganic metal oxides.  This limited and somewhat dull spectrum or pallet of colors was eventually broadened and enhanced during the early 19th century.  Some new colors were created then, when mixtures of metal oxides and earth pigments were cooked and fused together under high heat.  Finally, by the end of the 19th century, advancements in a new field of science known as organic chemistry enabled the creation of several intensely vibrant colors.  Modern synthetic pigments, inks and dyes are based upon the carbon molecule and were created in laboratories.  Today almost every natural pigment has been replaced by a synthetic organic alternative.  Modern pigments behave differently, not necessarily better than older mineral pigments in that when mixed or thinned down they generally shift in “value” and not in “chroma”.

https://commons.wikimedia.org/wiki/File:Munsell-system.svg This image © 2007, Jacob Rus

Some common earth pigments include green earth, goethite, ocher, hematite, sienna and umber.  Some natural mineral pigments include Malachite, Vermillion and Lapis Lazuli.  Some artificial mineral pigments not found in nature are Venetian Red and Caput Mortuum.   Some organic pigments of natural origin would include carmine, gamboge, Indian Yellow, madder root and mummy brown.  Some synthetic inorganic pigments that are manufactured include Ceruleum blue, Prussian blue and Cobalt blue, Cadmiums and White Lead.  Some synthetic organic pigments (lab created / carbon based) include the azo pigmens, dioxazine, isoindolinones, quinacridones and phtalocyanines.  There are too many pigments with too many details to define them all properly here.  Entire books have been dedicated to the subject. The vast majority of pigments available in the marketplace today are actually synthetic.   A short, far from complete list of traditional, non synthetic paint pigments follows.

Green Earth is similar to ocher; a mixture of ferrous hydroxide and silicic acid.
Goethite (Brown Ocher) is a unique mixture of ferrous hydroxide.
Ocher (usually a yellow) is a clay that contains hydrated hematite (an ore from which iron has been smelted for the last 6,000 years).
Hematite (usually red unhydrated mineral iron ore) stems from a Greek word for blood. “Limonite” ore comes from the Greek for meadow (meadow/ marsh/ bog ore/ brown / yellow). Ocher then is a catchall phrase for abundant natural earth pigments containing iron oxide and depending upon hydration states and additional ingredients may range in color between yellow, red, purple and brown. The artist and painters of the Medieval and Renaissance period knew how to cook ‘ochers’ with heat to drive away the chemically bound water, achieving unique hues.
Sienna (usually brown) is a mixture of iron oxide and manganese oxide. Yellowish-brown “raw sienna” is turned into a reddish-brown “burnt sienna” when cooked with heat.
Umber (both raw and burnt) is also a mixture of iron hydroxide and manganese oxide. It is usually darker than either ocher or sienna.
Malachite (usually green) is a hard copper carbonate mineral. It often comes from underground stalactites. <pic>
Ultramarine (deep blue) was originally made from crushed Lapis Lazuli. It was an extremely expensive pigment that was hard to make and it was used sparingly. <pic>
Venetian Red pigment comes from red iron oxide but it is artificial because it is or was collected from heated chemical waste of manufacture.
Caput Mortuum (usually purple) from Latin – meaning “worthless remains” was usually collected from leftover, useless iron sulfate (copperas) residues.
Carmine pigment (crimson or bright-red) is obtained from carminic acid.  Since carminic acid wasn’t reproducible in the laboratory until 1991, it has since ancient times been acquired by crushing up little scale insects.  Polish cochineal and Kermes dyes were both from scale insects and known in ancient Europe and were later valuable commodities in the Middle Ages.  Mexican or Spanish cochineal (from a different, New World scale insect that eats prickly pear cactus) quickly became the preeminent scarlet dye in the 16th century.  Although carmine or cochineal are better known as food colors, lipstick and fabric dyes today, artist like Michelangelo also used them in paints.
Madder root has been used since antiquity as a (red) dyestuff, but it has also been used for tinting paints. It wasn’t known in Europe until returning Crusaders brought it back to Italy. During the Colonial Period the typical red uniform of the British Army was dyed with madder root, while the officers that could afford it had their own uniforms tailored and dyed with brighter and more colorfast carmine or cochineal dye.
Gamboge is a saffron / mustard yellow pigment that is obtained from the sap or resin of a tree. It is the traditional color and dye used for the robes of certain Buddhist monks. It is often used in watercolor but is not lightproof.
Indian Yellow is was collected from the urine of cows that ate mostly mango leaves. It is a natural organic “lake” pigment. Authentic Indian Yellow is quite permanent, very expensive and often imitated.

Uranium Yellow from uranium oxide; often found in vanadium ore, made a useful pigment before the Manhattan Project found a better use for every available bit of the element in the 1940’s.
Orpiment (yellow) and Realgar (red) were both popular since Roman times as pigments.  The two pigments differ slightly in chemical composition but both consist of poisonous arsenic sulfide.  Arrow tips were occasionally dipped into solutions of these minerals to make them more deadly.  The minerals were originally found as crystalline deposits nearby volcanic fumaroles and geothermal hot springs.
Vermillion (bright red or scarlet) comes from the crushed crystal of mercury sulfide known as “cinnabar”.
Emerald Green was a very poisonous and dangerous pigment made from copper arsenate. By itself it made a durable and attractive pigment but would later turn black if mixed with sulfur colors (like cadmium yellow, vermilion and ultramarine).
Mummy Brown was a very useful and popular paint pigment made from the crushed up remains of Egyptian mummies. Most artist in the past did not know of its true origin. Perhaps some pigment called mummy brown was produced by burning ‘green earth’. Mummy Brown was still being made in the 20th century until sources of available mummies finally ran dry.
Asphaltum or bitumen is a brown / black pigment derived from solidified petroleum. It might be used as a binder for gravel and sand in asphalt road surfaces but it has also been used as a pigment. Ancient aboriginal N. American Indians used it to decorate pottery and Henry Ford used it to paint automobiles.
Ceruleum Blue; a synthetic inorganic pigment made from copper and oxides of cobalt
Prussian Blue (also Paris Blue or ferric ferrocyanide) was the first modern synthetic pigment. It is a dark blue, non poisonous, iron-cyanide based compound with intense chromatic power. It was the main color of uniforms used in the Prussian Army and was the traditional blue used in “blueprints” (or cyanotypes – which exploited the light sensitivity of paper perhaps, coated with gum Arabic & ferro-gallate (acidified iron) type solutions).
Cobalt Blue is made from heating together cobalt and aluminum oxide. Some Chinese porcelain pottery has mixed the same minerals for many centuries but blue glass and cobalt blue paints have been used now for about 200 years.
Cadmiums are very vibrant and light-fast yellow, orange and red pigments made from oxides of cadmium. They are expensive pigments, potentially toxic and superior to modern organic alternatives in almost every respect. <link Europe ban>
White Lead (or Cremnitz White) is lead carbonate and has historically been the principal white pigment of classical European oil painting. When mixed with a dryable oil it spreads wide and covers especially well and with high opacity. White lead paint was once commonly used to protect the hulls of wooden ships from shipworm. Unfortunately lead paint has been banned in most countries because of its potential toxicity and ‘titanium white’ has replaced it. Lead carbonate is the same substance that forms white crystals on terminals of a car’s battery. Historically the pigment was produced by subjecting lead to the fumes of strong acetic acid <vinegar>. Red Lead paint on the other hand is lead oxide and was once very valuable as an anti-corrosion / rustproof primer paint. For example this primer distinguished and protected the Golden Gate Bridge near San Francisco for thirty years before re-painting became necessary and before the formula was changed.
Titanium White is titanium dioxide (Ti O2) and is non poisonous. It has great covering power and is bright – with a high refractive index.
Zinc White is zinc oxide. It is a very useful non toxic pigment developed about 170 years ago that tints less or is more transparent than titanium white.
Zinc Chromate when used as a pigment was known as Zinc Yellow.  It is not used in art anymore because it degrades quickly to brown and is toxic and carcinogenic.  Zinc chromate does make a very useful paint coating in industry where it is used to passivate (protect from corrosion) metals like tin alloy, galvanized steel, cadmium, magnesium and aluminum Metal tools that have undergone a chromate conversion coating usually display a distinctive yellow-green iridescence.

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Dyes

Again, the difference between a pigment and a dye is that one is soluble and the other is not.  Inks incidentally, can be either dye-based or pigment based solutions.  Paints need a binder to hold little solid particles of color pigment to a surface.  Dyes on the other hand contain infinitesimal refractive coloring compounds that are dissolved in solution.  Pigments are generally better than dyes in keeping their color by resisting damage from high heat, bright light or chemicals.  Dyes can cling to or be absorbed into only a few types of surfaces.  Without special preparations, dyes cannot be turned into the pigments used to color paints.  Therefore a “laked pigment” is one wherein a soluble dye is absorbed by or chemically bonded to a transparent insoluble salt; which then leaves behind a particle of insoluble pigment.  Calcium salts from sources like bones, chalk or white clay were historically the first salts used to entrap dyes for use as pigment.  Today chromium and cobalt metallic salts are more frequently used to manufacture lake pigments.

From ancient times people have been dyeing fabrics and leathers and furs.  Woad, weld and madder are natural dyes that have been used for the last 3,000 years or more.  Today dye chemist are busy designing ever better molecular dyes, for the examination of neurons in a nervous system or to study DNA by examining specific genes.  Other dye chemist might be busy perfecting a contrast dye for use by an MRI (Magnetic Resonance Imaging) machine or inkjet solutions for 3D printing or microcircuitry fabrication.  Here they would need to consider electrostatic properties, solvent compatibility, resistance to bleeding and spreading, consistency and flow properties or perhaps the adhesion of dye or ink to a substrate.

Wool and other so-called “protein fibers” like hair and silk are the easiest fabrics to color with a natural dye.  First the oils on fibers like wool need to be washed or “scoured” away before a dye can penetrate.  Cellulose fibers like cotton, linen, flax, hemp, jute, paper, cane, rattan, etc. are less suited to natural dye uptake and may need to be treated beforehand by a mordant.  A mordant is a chemical used in solution that helps embed color into a fiber.  Taken from a French word that means “to bite” or to take hold, a mordant allows the penetration of a dye into fiber,  similar to the way a laked pigment binds within a crystal.  Some “substantive” or “direct” natural dyes like those from walnut hulls, Tyrian purple from a sea snail, lichens, onion skins, tea or coffee will stain and stick to wool without the help of a mordant, but these might eventually wash out or fade.  Substantive or direct dyes without assistance of a mordant cling to fibers by relatively weak hydrogen bonding.  Other types of dye molecules however can attach to fiber molecules by complicated Van der Waals forces or by ionic or convalent bonding.  The most permanent dyes are fiber reactive dyes that establish strong covalent bonds.

The most common mordants are alum, copper sulfate, chrome, iron sulfate, tannic acid and tin.  Some of the direct dyes already contain a tannic acid mordant (ex: walnut, oak and pecan husk, tea & coffee).  The choice of mordant will usually influence the outcome of the dyed color.  Alum (aluminum potassium sulfate) causes the least change in color.  Copper sulfate (Blue vitriol) sometimes turns fibers green.  It can be collected by soaking dirty old pennys in acid.  Iron sulfate (copperas) “saddens” color and makes them more green-brown or gray.  Historical “iron gall ink” employed iron sulfate.  Copperas can be made by soaking rusty nails in sulfuric acid.  Tin (stannous chloride, specifically) brightens colors, especially reds and yellows, but it can be very harsh on fabrics.

To bring this complicated topic to a shortened end so that this blog post can be published today rather than next month; many details about dyeing will need to be skipped for now.  The goal at present is to explore dyes insofar as they intersect with pigments and paints.  Perhaps this segment on dyes will be amended later.  More time is needed to compress information and to insert little details.  For instance, for forty years following its invention TNT was used only as a yellow dye.  TNT is so insensitive it took that long to find a satisfactory way detonate it.  Poke berries are not commonly used for either dye or ink; but the final draft of the American Declaration of Independence was penned in fermented poke berry juice.

Paint recipes

The Internet is loaded with recipes for children’s paints.  These may contain binders of soap, glue or flour and pigments of Kool Aid ® or food coloring and the like.  One may find a recipe for creating a paint from egg yokes and colored chalk.  { Michelangelo may have used the same tempera ingredients on the Sistine Chapel but since he painted upon wet plaster the work is called fresco, remember }.  Digging deeper one can find recipes more applicable for bulk paints.  There is no need to replicate here, the work already done on another web site.  One decent site providing information for homemade paint is provided by motherearthliving.com.  The following list of ingredients for “Clay paint” is copy and pasted here, as insurance against the possibility of “link rot” in the future.  The paint’s final color would be determined by both the hue of the powdered clay chosen and by any auxiliary pigments added.

CLAY PAINT
1 part wheat, rice, rye, or potato flour
2 parts cold water
1-1/2 parts boiling water
1 part powdered clay
1/2 part inert powder filler (options: mica flakes and powder, chalk, powdered ­marble or silica, 60- to 80-grit sand for rougher surfaces)

Gritty “chalkboard paints” similar in texture and performance to the slate chalkboards found in old school rooms can be created from either commercial latex (emulsion) paints or homemade paints.  One simply adds plaster of Paris, baking soda, un-sanded tile grout or calcium carbonate to the paint.

A simple black paint can be made from potatoes.   Several potatoes are slowly baked in a fire or in an oven until they turn completely black and dry inside.  These are then crushed to a fine consistency and the powder is mixed with linseed oil.  For a useful olive drab (Army green) color one can add yellow ocher pigment.

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Vinegar

From a copper engraving of a plague doctor in Rome, circa 1656

Across Europe between the the 14th and 17th centuries, a number of ‘Plague doctors’ donned protective suits like this to walk among dead and dying plague victims. Unsure of what might be causing these plagues, these suits were armor against a hazardous environment and are quite reminiscent of modern day hazmat suits. The image above depicts a late example from the city of Rome, complete with heavy cloak, leather gloves, glass goggles and conical birdlike beak covering the mouth and nose.  The impression of a carrion eating, scavenging crow or raven is almost impossible to miss.  Perhaps this engraving was intended as an early macabre from of editorial cartoon.  The significance of the conical or pointed beak is that various herbs and powders were stuffed into its end, in hopes of filtering out any lurking invisible plague vapors that might be inhaled.

Today, centuries later, some carnival costume mask may remind us of those heinous plagues. During the “Black Death” as much as half of Europe died in the span of four years.  There were many large epidemics  in history that are somewhat erroneously called “plagues” since these were probably not caused by the infectious pasteurella pestis bacillus. From antiquity to present the number of proper plague outbreaks caused by this bacillus though, might still number well over one hundred.  Between the 14th and 17th centuries the plague quit, then returned about 15-20 years later (almost with every generation).  The European rat population (where the bacillus is apparently not endemic) was repeatedly wiped out and took time to recover as well.

It is generally accepted however that there were three ‘great waves’ of plague pandemic in world history. The first noticeable “great” plague is called the “Plague of Justinian”. It occurred in 541 AD and was centered in the Eastern Mediterranean / Byzantine Empire area. As many as 5,000 people a day died in the streets of ancient Constantinople (by far the largest city in Europe at the time – named Istanbul today). In a year’s time this bout of plague killed perhaps 25 million people including the emperor Justinian himself.


The next and biggest great die-off is known as the “Black Death” which began in 1346 and lasted for seven years. This plague decimated perhaps 75 million people or approximately 1/6th of the world’s population. It is thought to have made its way from China or Central Asia (where the bacillus is indigenous in local rodents) along the Silk Road by caravan to the Mediterranean Ocean where ships carrying other rats or mice – further disseminated bacillus carrying fleas to ports throughout Europe and North Africa.   Europe especially, was remodeled by the Black Death.

The less disruptive, less specific “Third Pandemic” as it is called, lasted for more than a century (between 1855 and 1959) and was responsible for at least 12 million dead in China and India.  During this period the pneumonic form the plague ran rampant in Mongolia. All of the major epidemics of plague are thought to have originally blossomed outward from Central Asia.   Right now the pasteurella pestis bacillus can be readily found on any day, in the dirt or among rodent colonies living on the Asian, African, North or South American continents.  There is an ongoing occurrence of bubonic plague today, in Madagascar which broke out in 2014 and hasn’t yet faded away.

In humans the acute infectious disease caused by the bacillus Pasteurella pestis occurs in three forms: bubonic, pneumonic & septicemic.  The most common form bubonic, is characterized by buboes (bumps or blisters / inflammatory swelling of a lymphatic gland, especially in the groin or armpit).  Pneumonic plague  infects the lungs instead of lymph nodes.  Less common than the bubonic form but more deadly, the pneumonic form can be contracted by a flea byte or by airborne inhalation of the virus from an infected person.  Septicemic plague attacks the blood and causes blood clots but is rare.  Which ever form of plague is encountered, treatment with antibiotics has supplanted the treatment with sulfa drugs used in previous decades.  Early detection is still paramount for survival.

Segue to Vinegar

Vinaigre des 4 Voleurs / Four Thieves Vinegar

There is a story with various versions that dates back to one outbreak of plague in the city of Marseilles, France.  It seems that four incarcerated thieves (possibly caught for robbing the sick or dead) were pressed into labor.  They were forced to handle, transport and bury the corpses of plague victims.  Miraculously, the thieves continued to survive this punishment detail day after day while others about them were dying like flies.   Apparently the thieves routinely applied a concocted ointment they received from a local medicine woman.  Their survival was probably the result of certain herbs in the ointment acting as a repellent to the plague carrying fleas that transmitted the pestis bacillus.  The salve or ointment started with white wine vinegar as a foundation to dissolve and preserve the essence of these herbs.  In a version of the “Four Thieves Vinegar” believed to be authentic; angelic, horehound, meadowsweet, wild marjoram, campanula, camphor, cloves, rosemary, sage and wormwood were used. At least the last six herbs listed have aromatics that repel insects – like parasitic plague infested fleas.

The English word “vinegar” comes from the French phrase “vin aigre” – which means sour wine.   For as long as mankind has had alcohol to drink (about 9,000-10,000 years) he has had vinegar too.   The ancient Babylonians used vinegar as a condiment and Cleopatra used vinegar to win a bet.
Any plant sugars in solution can be fermented to create alcohol.  That alcohol (ethanol) can by deliberation or by neglect be exposed to open air and subsequently turned into vinegar by a different fermentation caused by acetic acid bacteria.

The “acetobacter” genius of the acetic acid bacteria (acetobacteraceae) family is the one most commonly used to make vinegar or to supply vinegar fermentation starter cultures (often called the “mother of vinegar”).   Products that are labeled vinegar usually contain a minimum of 4% acetic acid while the remainder is water, flavorings and trace chemicals.   Vinegar doesn’t spoil if sealed and has a practically indefinite shelf life.  It may oxidize, lose its aromatics or lose some water to evaporation if exposed to open air but it does that slowly .

Types of vinegar

The most common vinegars are cider, wine, malt, rice, balsamic and distilled. Today those have been joined by many flavored or seasoned variants. Vinegar can be produced from all sorts of things including coconuts, honey, beer, maple syrup, potatoes, beets, malt, grains, molasses, dates, sorghum, fruits, berries, melons and whey.

Wine vinegar is self explanatory.  It can occur in a few weeks or months after acetic acid bacteria in the atmosphere come into contact with wine. Aceobacter can spoil a soggy wooden wine barrel for example, if this is left too long unfilled and unused.   Malt vinegar which is popular with “fish and chips” is of course equivalent to spoiled beer.   Beer is usually fermented from barley and barley malt.   Scotch whisky can be made entirely of malted barley.   Malt is grain that has been germinated and has started to sprout.   The term “distilled vinegar” is a tad bit misleading because the vinegar itself is not distilled – but it is made from a concentrated source of ethanol. Authentic “Balsamic vinegar” is a very prestigious and expensive product that is first cooked and reduced from a white grape must, then fermented and then aged for a very long time in a succession of different aging barrels.

Uses

* “acid is second only to salt for elevating the flavors of your cooking. Just a few drops of acid in the form of citrus or vinegar can make a dish more complex — “brighter”

Vinegar is an important foodstuff and food preservative.  Vinegar can also be used to remove rust, prevent dandruff, soften stiff paintbrushes, kill warts, clean glass, clean tile grout and toilet bowls.   Like a vinaigrette salad dressing, a mixture of olive oil and vinegar make a fine furniture polish.   After the famous Holy Roman Emperor / King of Germany and Italy known as Frederick Barbarossa (1122-1190) drowned in the Saleph River (modern day southern Turkey) during the Third Crusade, his army collapsed.   His body was put into a wooden barrel and preserved with vinegar for the long trip back home.

Many sauces and food condiments like mayonnaise, tomato ketchup, spreadable mustard and pickle relish contain vinegar.  When Americans see a preserved cucumber they say “pickle” while in Ireland, Australia or the UK people might call the same item a “gherkin”.   A gherkin is actually a variety of cucumber and a cucumber is far from the only produce that can undergo the “pickling” process.   Beets, carrots, onions, tomatoes, cauliflower, cabbage, peaches, cherries and pears are frequently pickled as well.   There are several variations of the pickled cucumber or gherkin including: half or full sour, Polish style, sweet, dill, kosher, bread & butter and cornichons – those tiny little tart French pickles preserved with vinegar and spiced with tarragon.

Salt which was treasured in the ancient world, was used to preserve meats, eggs, vegetables and fruit because it drew moisture out of the foods and in so doing it inhibited the development of bacterial spoilage.   Produce can be preserved by a few different salt curing methods like dry salting, brining (strong salt solution), low salt fermentation and pickling.  Low salt fermentation and pickling with vinegar are similar processes in that lactic acid created in the first instance or acetic acid introduced by the second process, both lower the pH to a level that is hostile to bacteria. It takes a pH of about 4.6 or lower to kill most bacteria.  Clostridium botulinum is the tough, resilient and dangerous anaerobic bacteria that can flourish in stored foods that do not have high enough acid concentration or that were not heated hot enough or long enough when they were canned.

There are two traditional ways to go about pickling; the slow way by fermentation or the fast way with vinegar.  The fast way involves soaking some vegetable example in a salt bath overnight. This removes some water and better allows vinegar afterward to penetrate the vegetable’s tissues.   Alternatively, pickling lime (calcium hydroxide) is used instead of salt for this initial step.  Lime has the effect of making a vegetable like the cucumber crisper; it is there for the texturing effect alone and not for preservation.  The lime or salt solution is rinsed off after about 24 hours.  Vinegar, accompanied usually with antimicrobial pickling herbs and spices (like cinnamon, mustard seed, cloves & garlic) is then added.

German sauerkraut, Korean kimchi, sour and dill pickles are examples of the slower fermentation method of pickling which might require a couple of weeks to a couple of months.   Surrounding produce in brine solution deprives undesirable bacteria (most types) oxygen to grow but creates a favorable anaerobic environment for lactic acid bacteria.   Lactobacillus bacteria then ferment or convert natural sugars into lactic acid.

* A typical process for making sauerkraut using this slow pickling process is to place unwashed shredded cabbage into a sterilized stone crock.   Some outer leaves on the cabbages may be removed but wild yeast are to be otherwise retained.   Salt is repeatedly sprinkled between thin layers of shredded cabbage and packed firmly down.   Finally a dinner plate or something similar and additional weight (preferably in the form of a limestone rock) presses everything down; a sanitary cloth covers the crock.   In the process of waiting 4 to 6 weeks for nature to take its course: water is pulled by salt and pressed out by weight to form a brine solution.   Also a small amount of lime is dissolved from the rock which assists in the formation of lactic acid and provides the sauerkraut with extra flavor.

Products preserved by the two pickling processed mentioned above should be safe to eat for several months afterwards.   Cooking with heat and/or refrigeration will prolong their longevity as food.   High acidity should prohibit most bacterial growth but occasionally the acidity of vinegar (acetic acid) used or lactic acid fermented is not adequate.   To be considered safe for longer periods, even pickled foods need to be subjected to the ‘long time duration at elevated temperature’ of proper canning technique.

Making Vinegar

Just as with pickling there is a fast way and a slow way to make vinegar.  The fast way involves inoculating a liquor or fermented juice with a starter culture of bacteria called “mother of vinegar”.   “Mother” itself is a cellulose or complex carbohydrate that forms as surface slime on vinegar that is long exposed to air.  Acetobacter bacteria are aerobic which means they are oxygen loving or thrive in air.   In fast commercial vinegar production, a source liquid which already contains ethanol is started with this bacterial culture and extra air is added to oxygenate and promote the fastest fermentation.  The fast vinegar method may take only two or three days to complete.   Slow traditional methods for making vinegar on the other hand might require a few months – to a year to complete.  Here the acetic acid bacteria must be captured from the air before fermentation can even commence.  Here a potentially useful surface slime might build up that can be skimmed off and collected for use as mother elsewhere.

Homemade vinegar

Web pages can be found on the Internet which give step by step instructions for how to make vinegar from a bottle of wine for instance.  Usually these instructions call for the use of some Mother of Vinegar.   Little containers of this can be purchased online if need be, from places like amazon.com.  It is very easy however to make vinegar the old fashioned way.  The best results would probably be returned by starting with a jug of simple, unpasteurized sweet apple cider.  Taking the top off and letting the jug sit for a week or two will allow wild yeast to make the cider alcoholic.  Another few weeks of exposure to air will create apple cider vinegar.   Again, adding a little ‘Mother’ if it is available will help speed the process.  At some point after the homemade vinegar becomes strong enough, it should be bottled.  Vinegar should be stored in a narrow-neck bottle with a tight seal to prevent oxidation and loss of flavor.  New vinegar should be aged for at least several months, to clarify and allow the flavor to mellow.

* Vinegar eels are just barely visible and it would take about sixteen mature ones laid end to end to equal one inch in length.  These tiny nematodes () like to hang out and breed in vinegar.   They consume the bacterial and fungal microbes that form “Mother of Vinegar”.  These worms can inhabit many vinegar products that are left too long exposed to air, because their microscopic eggs often ride dust particles that float around in the air.   In the U.S., commercial vinegar is filtered or pasteurized to eliminate these little creatures, but they are not toxic or parasitic.  Like the brine shrimp that are larger, vinegar eels are actively cultivated and used as food for young aquarium fish fry (baby fish).   A hobbyist might grow a culture of eels from apple cider/vinegar because their eggs come with the apples naturally.

*To make juice, apple fruit must first be macerated and squeezed through a press.  Filtered this becomes apple juice, unfiltered this becomes soft or sweet apple cider.  Fermented the juice becomes alcoholic – hard apple cider.  If frozen, ice can be pulled out leaving less water so this more concentrated form of hard apple cider becomes “applejack”.   The same process can be accomplished with a bottle of wine or beer but some of the liquid must be removed beforehand to prevent ice from bursting the bottle when it expands.  Of course this process would be illegal almost everywhere booze is normally sold because it is considered to be distillation (freeze distillation).  You don’t want to deprive your government of one of its most lucrative tax bases.

*The drip still can be made from pots and pans from about the kitchen. Euell Gibbons published images of the concept more than fifty years ago. A simple apparatus like this is appropriate for collecting the oils and fragrances of herbs. Just toss a handful of rose pedals or other herb into the water of the bottom pot.  Apply heat and droplets of vapor will condensate and drip into the cup.

 

Considering Leather

The most utilitarian and multipurpose material ever readily available to early man came from the hide of an animal.  Making leather from hides or furs from skins might have been the first human industry.  Until the very recent dawn of plastics and synthetic fibers, leather and fur were nearly indispensable commodities.  Leather is a superior material for several applications like footwear, saddles and upholstery and still remains the material of choice over any synthetic alternative.  However, turning a smelly raw animal skin into usable leather is a difficult process.  Before certain procedural and chemical advancements in the previous century, commercial tanning was even yet a more laborious and time consuming pursuit. This post will endeavor to briefly separate and identify some of the varied techniques used in leather tanning, while perhaps empowering some readers with a few ‘do it yourself’ type leather tanning skills.

What is leather?

A mammal’s skin or hide consist of a thick center layer called the “dermis” or “corium” which is sandwiched between a thinner epidermis on the outside and a subcutaneous fatty layer on the inside.  The corium of a fresh hide contains between 60-70 percent water and 30-35 percent protein by weight.  Of that protein about 85 percent is of a special fibrous type called “collagen”.  These protein fibers are held together by chemical bonds.  Tanning chemicals (tannins, enzymes, acids, bases or salts) in effect alter these bonds between collagen fibers, remove water and dissolve natural fats within a hide.

If a fresh hide can be frozen, salted or quickly dried then it can be temporarily spared an otherwise inevitable decomposition from bacterial rot.  A fresh hide may have a few useful applications in raw form though, considering its tendency to shrink substantially upon drying.  However should dry rawhide be re-hydrated, it immediately becomes susceptible again to rot.  Raw hides have value and those destined for leather processing are soaked in brine or packed in salt at the slaughterhouse before being shipped to a tannery.  Should they desire, tanneries could preserve surplus hides for over a year by packing them in more salt.  Tanning is both a physical and chemical process that preserves a hide and converts it into leather.  The removal of membranes and subcutaneous fat from the underside and the optional hair removal on the topside entail just one or two physical processes.  The chemical processes reorganize some organic molecules, while often coating or replacing others with outright inorganic substitutes.

The leather industry has an odorous history and one accompanied by pollution. Today there are three distinctive methods to use for tanning a hide: by the ancient vegetable process, modern chromium process or novel aldehyde process.

Tanning liquors

Historically either alkali or acidic solutions have been used in tanning.  A Native American Indian might have soaked a deer hide in a potash solution for example.  Also called “lye”, this caustic alkali or base solution of potassium carbonate can be created simply by leaching water through wood ashes.  Lye (potash/potassium carbonate, sodium hydroxide/caustic soda & potassium hydroxide) or other alkali solutions like hydrated lime will remove the hair from hides.  Both sodium sulphide and sodium hydrosulphide will dissolve hair.   Even some weaker alkaline solutions like ammonia collected from human urine; have the effect swelling the hide, enlarging follicles and loosening hair at the root.

* Several centuries ago in urban areas like 16th century London, it was common practice for poor children to collect urine from private “chamber pots” and public “piss pots” to sell it for money.  Urine is a rich source of urea and decomposes into ammonia, which was an important source of nitrogen to factories that could not yet synthesize such a chemical independently.  At least three important industries required urine back then.  Textile manufacturers used ammonia for altering the color of vegetable dyes and adjusting pH in dye baths, gunpowder makers needed the nitrogen found in urine to make critical potassium nitrate and tanners also needed or favored urine to produce leather. 

* Even back in ancient Rome, urine pots were placed in the streets for the public to fill at leisure.  These pots were collected and used to wash laundry.  The laundry came out bright and clean and the practice was so popular that Emperor Vespasian taxed this urine in the 1st century AD.

* Today household ammonia (5 – 10% pure ammonium hydroxide) is still critically acclaimed for its general cleansing ability, including for laundry.  Just don’t mix ammonia with bleach (calcium hypochlorite) because that will create dangerous fumes.   

Two mildly acidic and astringent chemicals used to produce leather are alum and tannin.   Alum (or specifically hydrated potassium aluminum sulfate) is used as a blood coagulant in articles like styptic pencils, in underarm deodorants, as a dye-fixer or mordant for wool and plant fibers and in tanning solutions where the hair or fur might want to be retained.  Alum creates a less toxic alternative tanning liquor and for small jobs is being used more frequently now than it ever was in the past.  Tannin is easier to find as it occurs naturally in the bark and leaves of several different plants. This astringent polyphenol binds to and coats collagen proteins, making them less water soluble and less vulnerable to bacterial decomposition.  Tannin is but one type of polyphenol out of thousands, and these phytochemicals give vegetables and fruit both their color and beneficial antioxidant properties.

* Astringents taste bitter to the tongue, pucker up the mouth and tend to shrink or constrict body tissues in general. An astringent tanning liquor then can be expected to tighten its hold upon hair, as opposed to a lye liquor that would swell and loosen its hold. 

* Tannin from tree bark is far more traditional than tanning liquor from alum. By the early 17th century Industrial Revolution, large plots of the northern English countryside were being ravaged to mine alum rich shale deposits, which were then baked in bonfires using all the firewood from the surrounding landscape.  Probably more of that alum found its way into textiles than leather but by this time England was running out of trees too. 

In the past the commercial treatment of leather with tannin required massive amounts of tree bark (approximately an equivalent weight of bark to the weight of a skin).  In America, after the forest near early Boston and New York City were denuded, tannin harvesters ascended to the Catskill, Adirondack and Allegheny mountains to placate their ravenous need for tannin. Whole hemlock forests were flattened of trees, merely for the tannin in tree bark while the softwood was largely abandoned. The practicality of building tanneries closer to the source of tannin and then shipping hides long distance rather than tree bark was eventually realized.  Leather tanneries often formed the central economic hub of many new communities in American outward expansion.

The word “tannin” is derived from a German word meaning oak.  Several different plant species (including chestnut, eucalyptus, mangrove, maple, sumac, wattle, and willow trees or bushes) are high in astringent tannin and are commonly used in vegetable tanning liquors.  It would be possible to leach a tannin rich tea from the dead leaves of most any deciduous tree in the autumn.  Some people have boiled bran (the husk of wheat or rye kernels) to obtain tannin.   Hemlock tends to make leather reddish-brown while oak produces yellowish-brown and chestnut while famous for making thick Italian shoe-sole leather, turns collagen fibers dark brown.  Before introduction of chrome tanning solutions in 1858, most all leather produced was simply “vegetable tanned” leather.

Keith Weller acquired from USDA ARS (Website)

Keith Weller acquired from USDA ARS

So around the same time that the trans-American railroads were being constructed, Texas cowboys were driving cattle herds up to meet the railhead and jobless Civil War veterans were harvesting wild buffalo for meat; new chromium leather tanning techniques were suddenly gaining favor in Europe.  The new rails were soon used to ship cattle back east (notably to Chicago) and products like buffalo hides back further east to established tanneries perhaps in Boston or New York City.  The fact was that those eastern American tanneries relied upon much human labor and slow vegetable tanning chemistry.  Typically a cow hide might need to soak in a barrel of tannin liquor for six months to produce high quality leather.  Although not especially desired or in demand by American tanneries, a few bundles of Buffalo hides made their way to England; where they were enthusiastically received and thousands more were immediately ordered.  The decimation of the great American Bison herds is directly traceable to bovine diseases spread from domestic cattle and the commercial slaughter demanded by global economics.  In a twelve year period beginning in 1871, about six million buffalo hides from approximately nine million animals slaughtered – were shipped to Europe.

Chrome

Somewhere back in the middle of the 19th century, the effects of Chromium (III) upon a rawhide were discovered.  These solutions came from dissolving elemental chromium in sulfuric or hydrochloric acid. Two solutions, chrome alum (or chromium (III) potassium sulfate) and chromium (III) sulfate are noteworthy in tanning.  The latter of the two solutions is the simpler, cheaper form preferred today by the commercial tanning industry.  Not nearly as toxic as the hexavalent chromium (IV) variety of chrome used on shiny automobile parts, chromium (III) tanning liquors nonetheless contain heavy metals and should be disposed of carefully.  In the right pH environment chromium (III) can oxidize into undesirable and environmentally persistent chromium (IV).   Chromic acid which is different but related, is noteworthy for being a strong and corrosive, oxidizing agent that will attempt to consume organic compounds.

About 85 percent of all leather today is chrome tanned.  ‘Chrome tanned leather’ is thinner, more eaten away and more flexible than ‘vegetable tanned’ leather.  Chrome tanned leather is good enough though for most situations and may even be the preferred choice in a few applications; given its flexibility and better resistance to shrinkage caused by water.  Some chromium remains behind in the hide after tanning, as it is tightly bound to the collagen proteins.  The reason that chromium has become so ubiquitous in today’s tanning industry is because it allows great reductions in both time and labor.   Vegetable tanned leather which is more expensive, is usually reserved for quality items like belts, purses, wallets, shoe soles, horse bridles, harnesses and saddles.

Both vegetable but especially chrome tanned hides are tumbled and pounded around in rotating drums like the museum piece imaged above.  Once the desired level of chrome penetration into the hide is achieved (which takes about 24 hours) the hides will come out “wet blue”; not the tan color shown.  Several varied finishing techniques would follow next.

Whereas vegetable tanning might require grueling labor for fleshing and stretching the hide and long months of exposure to tannins inside a vat, chromium tanning creates a product in just days or weeks.  The substantial chore of fleshing is much simplified by virtue of these chemicals dissolving most of those unwanted fatty tissues. The details of temperature, pH and other chemical factors are more complicated, critical and caustic with chrome than with vegetable tanning liquors.  In this present day and age, one can no longer just buy U.S.P. approved chromium potassium sulfate crystals from the local drugstore either.  Chrome tanning on an individual basis is not practical, but vegetable tanning is.

Aldehyde Tannage 

While chromium (III) solutions leave tumbled hides a color that is referred to as “wet blue” a newfangled process leave the hides “wet white”.  The first and most notable, quick working base chemical used in “chromium-free” aldehyde-tanning was the water soluble gas, formaldehyde.   Not creating the pollution that chrome does, some small amount of toxic formaldehyde residues nonetheless remain within the clothes, shoes and car seats made with this leather.  A newer chemical called glutaradehyde is highly reactive towards proteins, but leaves aldehyde wet white leather comparatively ‘baby safe’ and allergen free.  Glutaraldehyde is more expensive than formaldehyde, it sterilizes or inactivates viruses and bacteria, it is used to remove skin warts and is occasionally used in hydraulic “fracking” fluids to unclog oil wells of microorganism buildup.

The American Indians and probably many other nomadic aborigines as well typically used the brains of an animal during the hide tanning process.   Boiling the brains with a bit water creates an oily soup that can either be used as a solution to completely submerge and soak a hairless hide or be rubbed into the underside of a fur.  Once the treated skin is smoked over a fire however, chemical changes occur and a mild aldehyde type tannage takes place. Almost any organic oil benefits the flexibility and durability of leather.  Some famous leather ointments like Neatsfoot oil however will darken leather while brain oil is less likely to.

*Neatsfoot oil (a brand name) actually comes from the tibia (lower leg –shin bone) of a cow; it doesn’t easily freeze and absorbs readily into leather.  Sulfating the Neatsfoot oil allows it to penetrate even further. 

Price of rawhide

The U.S.A. is only the eighth largest producer of leather in the world, with a total 669 million square feet produced in 2011.  The other top ranking leather producers superseding the U.S. that year were: China (3,913 M sq. ft), Brazil (1,832 M sq. ft.), Italy (1,573 M sq. ft.), Russia (1,460 M sq. ft.), India (1,397 M sq. ft.), South Korea (1,083 M sq. ft.) and Argentina with 715 million square feet of leather produced.

In the 1990’s the price of a wet nondescript cowhide in the U.S.A. was approaching $1.00 per square foot. Today’s price for a wet steer hide (over 53lbs.) from a slaughterhouse is about $70.00.  Because of its potential as leather, raw cowhide is generally more valuable than pig, sheep or goat hide.  However if the hair is to be retained then hair quality or unusual coloration like Angora goat or Holstein cow can fetch much higher prices.  There are authorities on this subject.

The price of meat influences the price of leather.  Tanneries must compete with food companies to get the hides because what is not converted to leather is immediately converted to gelatin instead.  Gelatin is made by boiling the collagen from skins, tendons, ligaments and bones in water.  Europe produces a large share of the world’s gelatin, supplying about 400,000 tonnes per year.  More pig skin is converted to gelatin than is cow, sheep or goat skin.  Gelatin itself is used in puddings, candies, marshmallows, ice creams, cakes, shampoos and miscellaneous cosmetics.

Removing the hide

 Flaying or “skinning” the hide usually takes one or more very sharp and slender knives.  These knifes generally dull quickly while skinning and need to be re-sharpened periodically.  The thickest skin on an animal is usually around the neck and shoulders.  The thinnest skin, which is more vulnerable to nicks by a skinning knife, is at the belly.   When removing the skin in one piece the starting incision is usually made from the chin, down through the center line of the belly, to the rectum.  From each foot, cuts running down the inside of the legs come down to meet the centerline.

Small the animals have thinner skins than large animals.  The most difficult skinning would have been preformed by a fur trapper that was compelled by market demands to tediously flay around the head, face and feet, or by a taxidermist who’s flaying gets even more intricate.  Furriers and taxidermist are rare these days but their profession still requires much more skill, patience and attention to the details of skinning than an average hunter would employ.

There is more than one way to skin a cat

Large industrialized slaughterhouses can remove a full grown steer’s hide in less than a minute.  Techniques differ but these factories usually employ moving assembly line division of labor or small teams working simultaneously on one carcass.  Skinners might use  pneumatic “roller skinners” or normal knives and a mechanized skin pulling apparatus.

factory skinner using a flaying knife

team using a hide puller

For small furs like rabbit and mink a commercial furrier might purchase or construct a hide pulling machine that quickly shucks the skin, leaving it inside out.  The only labor involved is making a few precise cuts beforehand, around the head and feet.

DIY Vegetable Leather Tanning

There are many, many books, pamphlets, magazine articles and YouTube videos detailing “do-it-yourself” tanning techniques.  The novice should focus on the overall intent of tanning and less upon one particular technique.  The intent is always to remove the natural water and fatty tissues from a skin and replace them with something else.  A novice should initially avoid tanning large hides and seek something smaller. The amount of labor required for a large hide (bigger than a deer or sheep) can quickly become discouraging or overwhelming for the un-initiated.  The first decision to be made is whether or not the hair should be removed.

Caustic lye, potash or lime would be normal choices for de-hairing solutions.  It is possible however to simply submerge and tie a deer hide perhaps in a cold mountain stream and leave it there for a week or two. Returning later one will find that the hair pulls out easily by hand, no caustic solution was needed.  Many sources are adamant that the first thing to do with a hide is to scrape the flesh from the underside.  Alternatively though other tanners might prefer soak a hide first, thereby loosening both hair from one side of the hide and softening those fatty flesh tissues from the other.  If the tanner of furrier decides to keep the hair then he skips the de-haring alkali bath and moves on to fleshing.

* Buffalo hunters in the past didn’t flesh their hides at all, but cured and preserved the hides for shipment by spreading on salt and drying them out in the sun.

The “Indians” native to North America were expert leather tanners.  Every bit of their clothing was made of leather and often their homes were as well.  For scraping the hide they used tools made of bone, rock, wood or antler.

Factories involved in vegetable tanning were also compelled to physically flesh the hide and they historically favored a fleshing knife and a beam.  The fleshing knife is simply a rather dull, flat strip of metal with two handles.  The beam was usually a short log angled from the workers waist, to the floor.  This provided a work surface that allowed the wet and heavy hide to be moved around easily, and provided a mechanical advantage by allowing the tanner to lean into the work with his weight.

polex3c

Once properly fleshed, either a de-haired hide or a fur with all its hair intact will undergo essentially the same processes afterwards.  While tannin will stain things brown it may be desirable for de-haired hides but an alum solution might be chosen for hairy furs.  Small animal furs might need to soak in a tanning liquor for just a few days whereas large hides might need to soak for weeks.   The judgment call of whether a hide has set in a particular tanning liquor long enough or not, is made by cutting through a small piece of hide and examining it in cross section.  If the sample cross section is the same consistent color throughout then this part of the procedure is finished.  The hide is now tanned from a chemical perspective but much physical labor remains.  Any pinkish-ness or fluctuation in color from the edge to the center is an indication to soak the skin some more.

At this point, should the treated wet hide or fur be simply tossed out upon the ground to dry, it would shrink, curl and stiffen into a very unusable product.  To get the strong but flexible leather we are familiar with that hide needs to be washed, rinsed, twisted or rung out like a towel and then thoroughly tortured as it dries.  A half dried skin can be laid over a tree stump and using a soft mallet, pounded over every square inch of its surface with short glancing blows .  At some point before all the moisture is gone, the leather is oiled.  It is this tedious but important, continual stretching, pounding and working of the skin as it dries, that produces flexible leather.

   Un-tanned rawhide can be preserved by drying it out.  If it is not to be tasked with some immediate purpose like being stretched over a hollowed out log to make a drum, then it can be saved for proper tanning at a later date.  Some rawhide might exist in a transition state, being only partially tanned.  Stretching a hide on a frame, or tacking one to a barn wall are popular methods of drying skins out.  Residual bits of fat or flesh can be scraped at leisure, either the suede or epidermis side can be attended to and once it’s flat & stiff the dried rawhide can be stored inside.

The novice or independent furrier has many options to improve his fur.   Furs can be washed in dish-washing detergent to remove oils and odor.  Vinegar and salt solution can be used to “pickle” the skin which helps “set” or lock in the hair.  The pickling solution is usually neutralized with baking soda before the fur hits the alum bath.  Once dry after the tanning bath, a fur might be rinsed in gasoline or naphtha (white gas used in camp stoves and lanterns) to remove any lingering oils or odor.  [Dry cleaners predominately used naphtha or another flammable petroleum fraction before 1911].  The flesh side of the fur might be sanded with sandpaper to remove high spots, making the suede uniform and level.  When finishing a fur it might be brightened by tumbling it in cornmeal, bran or sawdust which is then combed or brushed away.

Individual tanners working with a hairless hide might consider smoking it over a fire.  Some American Indian tribes once made the majority of their clothing from smoked deer hides.  After being fleshed, de-haired, cured in a bath of boiled tree bark tannin, worked to pliability and bathed in fat or brain oils, a deer hide was commonly draped over fire.  Being supported by a little tent like frame of green tree boughs the hide was rotated occasionally, collecting preservative chemicals and additional color along the way.

Once again, there are many sources and even videos of this topic available in the library or on the Internet.  Some of these sources have excellent information others do not.  The reader should be aware of several alternative vegetable tanning methods or recipes before religiously adhering to just one.

Other leather

   There are some schools that teach tanning and/or taxidermy and colleges or universities that offer chrome and aldehyde tanning curriculum.  There are products that disguise the origin of leather and some new organic products for vegans that imitate leather.  Often commercial leather is split, yielding at the least two different products; a “top grain” and one or more layers referred to as “split hide”.

Patent leather has a shiny, glossy finish and gets its name from a finishing and polishing process that was patented some two hundred years ago.  A satisfactory substitution or duplication of that process can be created by painting leather with layers of pigmented linseed oil (similar to oil painting on a sheet of canvas) and then with layers of varnish or lacquer.  Modern patent leathers (not vinyl or poromeric imitation leathers) usually have plastic coatings.

An “aniline dyed” leather refers to a very high quality ‘top grain’ leather that has been dyed clear through with a soluble dye.  A hide’s entire natural surface with pores and imperfections is visible with aniline dyed leather. No sealer, paint or insoluble dyes were used.  Should imperfections like scratches, blemishes or scars be sanded or disguised then the improved leather is referred to as “semi-aniline” dyed.  Most leather car upholstery is “pigmented” leather, meaning“semi-aniline” dyed leather with a heavy durable, protective, pigmented polymer surface coating.   Aniline is also a precursor used in the manufacture of polyurethane.

The Chinese were known to have boiled leather to make armor.  Probably many cultures over the centuries used leather armor but few if any examples exist in the historical record because they would simply biodegrade.   There might have been a lot of boiled leather armor back in medieval times but no one knows for sure now.  Boiling leather makes it shrink, thicken and harden.  Boiled in water or perhaps oil or tallow, the leather becomes mold-able for a short time and will freeze or set into shape as it dries. Overcooking makes it brittle and likely to shatter.  This site discusses making leather armor.

Authentic cheetah, giraffe, tiger and zebra hides are rare now but they were once fairly common.  Some leather producing outfits have taken to printing the hair of cow hides with ink, in patterns resembling these animals.   Even the hides of Holstein cows might be suspect.

As long as people continue to eat meat, there will be a continual supply of animal skins.  The rate of human population expansion is unsustainable and as a species we are soon to eat ourselves off this planet.  Nonetheless some vegans and or members of PETA (People for the Ethical Treatment of Animals) would have us believe that many animals are raised and slaughtered solely for the leather.  Aiming squarely for this demographic, companies like MuSkin, Myx and Mycoworks are actually growing, convincing leather substitutes by using mushrooms.   A substrate, matrix or mat of linen or hemp fibers actually gives this artificial leather its integrity and strength.  In essence either the chitin from the cap or the mushroom mycelium itself fills the spaces between mat fibers.   Apparently incubation and manipulation of fungus while growing can be controlled to a point where zippers can be incorporated without sewing.   Apparently members from the gilled Pleurotus genus and the non gilled Phellinus genus of woody mushrooms are producing the best mushroom leather  <images> or <other images>  results.

MISC informative LINKS

Some chemicals used in leather processing

Phenol

Hemlock history in New York

Buffalo destruction / global market

Ethnobotany of tannins

Leather furniture facts

World Statistical Compendium for raw hides and skins, leather and leather footwear 1993-2012   <PDF>

 

 

Curing & Preserving meat

 

steer2e

Although potentially a messy and inconvenient chore, the ability to procure one’s own food by slaughtering an animal is an essential skill for the well rounded and self sufficient individual.   This post offers some brief suggestions on how to butcher and process meat properly.  If fresh meat is not to be cooked and consumed immediately, there are some time honored meat preservation methods to choose from.  Jerking (drying), canning or salt curing & smoking methods easily come to mind.  Freezing may have become the most convenient way to preserve meats since WWII but these will still begin to deteriorate in other ways if they are left in a freezer too long.  Frozen meats are also dependent upon continuous uninterrupted sources of electricity.

Processing, curing and preservation methods may differ between animal species.  Raw fish for example, which begins to deteriorate very quickly can still be canned, smoked or turned to jerky.   The precautions for fish preservation differ by being more urgent.  Traditionally larger animals were butchered only when the climatic temperature dropped to levels that retarded meat deterioration.   It is no mystery why today’s deer, elk or moose hunting seasons begin in the fall.  When butchering large to medium animals like cattle, deer, sheep, goats or pigs, the first significant priority is to reduce the carcass’s internal heat.  The best way to do that is to bleed it, remove the skin and split the carcass.   There are probably as many detrimental fungi and bacteria lurking inside the meat as there are outside it.  The quick reduction of internal body heat in a carcass is the first step in reducing undesirable microbial or enzymatic deterioration of meat.  Snow banks and cold concrete floors can act as desirable surfaces in this heat reduction endeavor.

pre - 1911 "Reefer car" / Wikimedia commons

pre – 1911 “Reefer car” / Wikimedia commons

Refrigeration 

 In modern industrialized nations, refrigeration has changed our diet and has permitted the manifestation of the modern supermarket.  In urban areas, before refrigeration came along, fresh meat could be immediately consumed by a large populace, before it had a chance to spoil.  Before refrigeration and outside urban areas, meat harvesting was traditionally preformed in the fall or winter.  Cold temperatures assist in processing and preserving meat by discouraging bacterial activity both inside and out.  A century ago the availability (or not) of fresh meat and vegetables was dictated by seasonal and climatic temperature.   Initially commercial meat processors and brewers relied upon refrigeration from wintertime ice blocks cut from lakes and stored in sheds.  Properly ice ventilated “refers” or refrigerated railroad boxcars began shipping meat, dairy, vegetables and beer around the U.S. in the 1880’s.

US National Archives image /1917-18

US National Archives image /1917-18

Although invented a few decades before on both sides of the Atlantic Ocean, artificial refrigeration did not find successful application in the meat packing industry until the turn of the century and its accompanying delivery of commercial electrical power.  By 1914 artificial refrigeration was the norm for perishable food wholesalers and retailers.  Like milk or newspapers arriving on the doorstep, ice blocks were delivered to the ‘iceboxes’ of most urban homes.   In the 1930s, newfangled electrically powered household refrigerators appeared, but since coinciding with the ‘Great Depression’  – only the affluent could afford them.  Rural areas would wait much longer for delivery of electrical power.   After WWII, household refrigerators finally became common for the rest of the nation.

No longer restricted by the seasons, today we can buy fruits or vegetables “out of season” because they are maintained in a chilled state while being shipped from far away.  Likewise, supermarkets and groceries presently offer us plentiful supplies of fresh cut meats; due to the marvels of electricity, artificial refrigeration, and oil dependent transportation supply chains.

Vocabulary

 Curing– can be a vague term because it is a process where so many ingredients or methods used can apply.  The only essential ingredient in a cure is salt (plain NaCl / without iodine).  Salt draws moisture out of the meat and it shuts down most microbial activity.   Although humans like other animals require salt in their diet, and at moderate levels it may enhance taste; salt has actually been such a historically valuable trade commodity because of its capacity to preserve meat.  “Corning” is the process of treating raw meat to dry salt crystals (any type of salt:  pickling, rock, kosher, dairy or canning – but not iodized which may cause discoloration).  There are quick acting “dry” cures where salt crystals and perhaps additional dry spices are packed directly around the meat.  “Wet” cures are essentially brine solutions in which meat is submerged and soaked.  In either case salt causes water to be drawn out of both muscle tissue and out of undesirable microbes by osmosis.  “Pickling” meat generally refers to using a curing mix or solution that also contains sugar and extra spices.  Sugar or honey might be included in a cure to counteract the harshness of excessive salt and to keep meat moist and tender.  Some spice combinations don’t work – garlic and black pepper can overpower a cure.   A “hard cure” implies a process involving both salt curing and long term exposure to preserving pyroligneous acid from creosote in wood smoke.   A hard cured ham or slab of bacon can become very dehydrated over time.  “Ageing” is a term usually reserved for beef.  Quality, tender “premium” beef is sometimes “dry aged” and is usually only to be encountered in a good restaurant.  The general public can only purchase a compromised product from the grocery, referred to as “wet aged” beef.

   Jerky” is an Anglicized version of a previously Spainglacized (?) version of a original Incan word: “ch’arki” – meaning dried meat.  Although any meat can be “jerked”, venison and lean beef respond best to the process.   Obviously low air humidity is necessary for the process.  For simplicities sake the raw meat can be dressed into the form of large and wide, but thin slabs before being introduced to the cure.  Either a dry salt cure or wet brine solution should be applied to the meat.  Afterwards the individual slabs are cut into thin strips and spread on a rack.  Whither exposed to sunshine or spread on racks inside, the meat should dry enough eventually, to snap rather than fold when it is bent.   A dry cure might produce results more immediately, because a brine-cured meat might soak in solution for a 3-6 day period before being removed for drying.  Below is an example brine recipe that might as easily be applied to a ham as it is to jerky.

pick_brines

Canning

Naturally, meat can be canned at home.  This post won’t delve very far into the details of canning but the main thing to remember is that any improperly canned foods are subject to developing botulism.  Clostridium botulinum is a curious, heat resistant bacterium that despises oxygen.   So while a host of bacteria like salmonella, E.coli, and listeria monocytogenes are killed at boiling water temperatures (100 deg C / 212 deg F),  botulinum spores locked within an airtight can, bottle or glass jar – would not be killed.   To insure canned food is safe, home canners must maintain an elevated temperature for an extended time.  By using a large specialized pressure cooker known as a “pressure canner”, the cook is able to reach an abnormal 115.5 deg C / (240 deg F) temperature by essentially doubling the atmospheric pressure first.   To be safe, that high temperature is maintained an hour to an hour and a half.

Fish

The Carib Indians were smoking fish over fires to drive flies from drying fish jerky when Christopher Columbus discovered these “Indians” in the New World.  Almost every type of fish responds well to curing and smoking but fish with a high percentage of oil (greater than 5%) do not air dry well.  Oily or fatty fish that do not dry properly are often preserved by “corning” instead.  Three to four generations ago many people in coastal regions continued to salt pack fish away in wooden barrels in the same way others inland might have stored “pork butts” or bacon away in barrels.   Requiring no refrigeration, freshly cleaned and dressed fish were sprinkled with corning salt and then stacked in a keg.   After about four days the salt pulls enough moisture from the fish to create its own brine solution.   Then the fish are rotated and re-stacked in the barrel, more salt and fresh water are added until the brine solution covers all the fish.  The fish should be firm when the salt has completely penetrated through the flesh.  Before consumption, the excess salt is washed and rinsed away, and fish are soaked and refrigerated in fresh water overnight.

* In the Great Lakes region people have occasionally contracted ‘broad fish tapeworm’ – from eating uncooked pickled pike, walleye or other predatory type lake fish.  Freezing the fish before pickling eliminates this threat (as does cooking).

Fermented Fish

Several cultures have resorted to fermentation as a method of fish meat preservation.   In the Mediterranean, anchovies are allowed to ripen for at least one half of a year before they are considered ready.   Orientals might ferment anchovies, shellfish, squid or shrimp for more than a year to create that dark brown “fish sauce” they cook with.  Scandinavians might eat “Hákarl”, “Surströmming” or “Rakfisk” which are so odorous as to send normal people into flight.  Eskimos not only ferment fish but might toss birds, sea lions, walrus, whale parts or anything else with protein into the same earth covered fermentation pit.   Fish fermentation works because most bacterial activity is halted as the level of acidity increases.

Poultry

The same preserving techniques used for other meats can also be used on fowl.   Since fowl seems to dry rather quickly, brine curing solutions are preferred to dry ones.   Turkeys and chickens are seldom hard cured (smoked) whereas ducks and geese can be because of their higher fat content.

Beef

Driving out excess moisture from meat deprives bacteria and fungus a furtive environment to grow.  While salt cured pork hams and bacons may hang for years in a smokehouse, the primary purpose of a salt cure and of smoke is to dehydrate and preserve.  Only cheaper cuts of beef from the chuck, rump or brisket are improved by salt cure and smoke preservation.   Cures for beef will still employ salt, but are also sweetened usually with something like brown sugar, maple syrup, molasses or honey.

Pastrami, corned beef and ‘bully beef’ are salt cured and packaged or canned without being smoked.  Beef being a larger animal, has about twice the number of basic or primal cuts as does pork.  There is little agreement or standardization between cultures or countries on how a beef should be cut.  Thanks to refrigeration, beef can be deliberately aged to improve its character, but pork is seldom treated more than a couple of days this fashion.

Unless you go to some effort, the only way an individual is likely to encounter aged beef is to order it in a good restaurant.  The public has no access to properly aged beef in a grocery or supermarket.  Today meatpackers just inject the beef riding conveyor belts, with chemicals like sodium phosphate- which changes the pH of meat protein and allows it to hold more water and weigh more.  “Still wiggling” so to speak, the wet and fresh steak or what have you undergoes treatment with other chemicals, gasses and perhaps radiation, before it is hermetically sealed in shrink wrap and crated for shipment.  While in transport to a retailer, this commercial beef with which we are acquainted is euphemistically referred to as “wet aged” beef.

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chopped from U.S. Department of Agriculture poster

Dry aged” beef on the other hand is where a side of beef hangs in a refrigerated meat locker for many weeks as it tenderizes.  The meat locker is maintained just above freezing (34 – 40 deg F), allowing oxidization of fats and enzymatic breakdown of muscle proteins to occur.  Meanwhile gravity pulling upon a side of beef is considered to assist in fiber tenderization.  Only superior beef carcasses with good marbling (streaks of fat interlaced throughout the meat) are subjected to the expense of dry aging.  Dry aging allows time & environment for enzymes to break down muscle proteins into shorter fragments.    Exposed to free air, fat oxidizes and adds flavor to the meat.  Since the process requires extra time, storage space, electrical refrigeration and causes a split carcass to loose a good deal of weight through dehydration –aged prime beef cuts are uncommon and expensive.

Processing Pork

Pigs are very efficient animals to farm for slaughter because the majority (>87%) of their weight is converted to food.  A pig’s skin is often converted to food whereas a cow’s skin is not.  Pork lends itself better to salt curing preservation than does beef or large, lean wild game.  On the American frontier the hog was a cost-effective animal that was almost indispensable to early settlers.  Pigs thrive in most climates, eat almost anything and reproduce quickly.  With just a few pigs, farmers could feed their families through the winter, sell some or stash some extra meat away in storage and still have lard leftover to make things like candles or soap.  (* For candles, alum & saltpeter were added to harden tallow.)

* Noting the Jewish and Islamic taboos on eating pork, the restrictions probably made perfect sense to earlier civilizations in the warm Middle East.  Pigs can carry several types of parasites or viruses.  Trichinosis comes to mind but this encysted larva of a parasitic roundworm might be found in almost any type of wild mammal also.  Omnivorous pigs do have a more basic and quicker acting digestive system than do cattle (or humans), and they have no sweat glands to expel pollutants they might have ingested Pork is one meat that definitely should be cooked well.  That means reaching 71° C (160°F) temperature down deep next to the bone in a piece of meat.  From New Guinea to Hawaii the ancient Polynesians cooked pork in a pit; usually to a point where the meat just fell away from the bones.

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People who raise pigs for easy slaughter might prefer their shoats to be of manageable scalding size – say 45kg (100 lbs.) or so.   Immediately after killing a pig, “sticking the pig” refers to puncturing its carotid artery with a knife to let the blood run out quickly.  Since retaining the skin is often desired, the easiest way to remove the hog’s hair is probably to scald the carcass in boiling water.   Next the hair should be scraped off with a blunt edge tool similar in sharpness to the backside of a butcher knife.  Afterwards flame can be used to burn off any remaining individual hairs.   Actually surrounding a pig’s carcass with dry straw and setting the pyre afire is an ancient alternative to hair removal by scalding.

After scraping, the pig’s carcass is often hauled up into a tree by its separated hind legs.  This allows the blood and other fluids to drain, allows for easy separation of the offal and facilitates simple splitting of the carcass down its backbone.   Splitting down or through or beside the hard vertebra requires a tool like a hacksaw, reciprocating saw or heavy butcher’s  (not a flimsy Oriental type) meat cleaver.

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* Butchering can be preformed on a flat table also.  The following link to a video shows a skilled butcher doing just that.   Whole Pig Butchered Video

*Another video showing where bacon is located and how it is cut.

After being processed to the point of being split into halves or smaller “primal cuts” there are several avenues to take:  as in choosing between barbecuing, canning, freezing, etc.  This post is concerned with exploring the old fashioned smoke & salt cure methods of  long term preservation.  The majority of traditional curing recipes were intended to complement pork coincidentally.

Typically a ham or shoulder might be packed in dry salt cure (1 lb. for every 12 lbs. meat) and remain that way for at least (2 days per lb. of meat).  The same cut would remain submerged for about twice that long for a brine cure – or a month max.  Thinner bacon or loin cuts would differ by requiring about half as much salt cure.

For the thick ham and shoulder cuts a “brine pump” is very useful in preventing rot, by injecting cure solution down deep next to the bones.   Length of smoking period is a matter of taste, with 4 days being a minimum and no limit on a maximum exposure.   Virginia hams, already cured, might yet hang in a smokehouse for years.  Back in Colonial American days these hams were valuable and articles sometimes needing protection from theft.

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* “Boston Butts” or cuts of pork do not come from the rear end of a hog – just the opposite.   The name comes from colonial America and the way that these tender shoulder cuts were packed for export and in salt, within smallish or middling sized wooden kegs (the cask themselves were referred to as butts).  

Usually an experienced butcher will separate the loin and belly sections from the shoulder (top butt and picnic) section by cutting down between the 5th and 6th ribs.   Ribs are counted, beginning from the neck.  The loin region ends at the last rib.  The tenderest meat from either a pig or a cow comes from the tenderloin.  The tenderloin is a long muscle that doesn’t get much use, and it runs inside the rib cage and alongside the spinal column.   The “Filet mignon” cut steak comes from the smaller end of this muscle (the end further away from the hip).  The expression “Living High on the Hog” refers to eating or being able to afford the most tender and therefore most expensive cuts of meat.   As with cattle or any similar herbivore, meat generally gets tenderer as the distance from the hoof grows.

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hash of 4 altered public domain images

Ribs

Horses normally have 18 pairs of ribs, but occasionally 19 pairs.  The first eight pair of horse ribs are “true ribs” and the other ten are “floating ribs”.  Pigs have 15 to 16 pairs of ribs – depending upon breed.  For comparison humans generally feature seven “true” plus five “false” ribs, for a total of 12 rib pairs; except for an occasional human who may possess a pair less or a pair more than normal.  Cattle have 13 pairs of ribs.  “Chuck” cuts of meat come from the area surrounding the first five ribs on a side of beef.  In the U.S., “Rib” cuts of beef come from the area between rib #6 and rib #12.   The last or 13th rib marks the beginning of the loin region.

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Sausage

The bits and scraps of meat and fat left over after butchering are not wasted but put into sausage.   Traditionally the small intestines of the animal in question were washed carefully and stored in brine until used as the casings for stuffing.   Cleaning intestines is a tedious job as both sides have to be carefully scraped of fat and mucus.  Everything must be rinsed several times.   Someone today might opt to purchase artificial casings or perhaps purchase real hog or sheep casings on-line or from a butcher.

Any type of meat can be used alone or in combination to make sausage.  The happy balance between meat and suet in sausage seems to be somewhere around 2 parts lean meat to 1 part fat.  Too much fat makes a greasy sausage that shrinks, while too little makes hard and dry sausage.  Sausages can be hard cured and preserved for long periods, eaten immediately or frozen.  Seasonings to avoid if freezing sausages would be garlic, sage and salt.  Somehow the freezer makes the garlic tasteless and causes the other two to produce bad taste.

Besides casings the only other item needed to make sausage is a machine to grind up the meat.   Food processors can perform this function but leave the particles too small.   Expensive electric meat grinders perform admirably but are overkill for the occasional homespun sausage maker.  The ideal sausage grinder for occasional use might be a hand cranked model, invented over a century ago.   Smaller black & white reproductions of this approximately 117 year old poster below were probably placed in mail order catalogs.  A  funnel shaped attachment for stuffing casings accompanied the product.   Copies or clones of this chopper are still being manufactured today.

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Disease, toxins, worms and other nasties

Toxins or “biotoxins” are the poisons created only by living cells or organisms (all other poisons are correctly referred to as toxicants).  Some pathogenic viruses, bacteria or fungi may require oxygen, while others do not.  Acidity or the lack of, radiation like x-rays or UV light, freezing temperatures or high cooking temperatures and chemicals like salts, can all deter the detrimental effect of biotoxins in food.  There are at least two hundred different known diseases or maladies, transmitted through food to worry about.  Only a few short descriptions are listed here…

Clostridium botulinum which is responsible for botulism, is killed or inhibited by saltpeter (NaNO3 or KNO3), oxygen and high cooking temperatures. The most lethal neurotoxin ever discovered by mankind is named after a Latin word meaning – sausage.  “Sausage poisoning” was once more common than it is now.  A can of improperly cooked peaches may produce botulinum toxin.    Although it can kill quickly, contracting botulism these days is very rare, something like 10 cases a year in the U.S.   <see Alaskan Eskimos>   The bacterium is found throughout the world in the soil and in untreated water.  Some vain people actually pay a cosmetic dermatologist to inject this deadly protein into their face <see Botox> , where it has the effect of weakening or paralyzing facial muscles and removes wrinkles.  The toxins created by this bacteria are inactivated by cooking to 160 deg. F.   The bacteria itself is killed by 175 deg. F temperature but the dormant spores themselves won’t be killed until 250 deg. F is reached.

Salmonella is caused by eating food contaminated with animal feces.

Campylobacter jejuni is the most common cause of bacterial foodborne illness in the United States.

Listeria or Listeriosis is caused by the Listeria monocytogenes bacteria  and is the third-leading cause of death among foodborne bacterial pathogens.

Escherichia coli (E. coli) are bacteria that live in human and animal intestines.

Trichinosis is a fairly rare (now) parasitic roundworm disease, caused by eating undercooked meat containing the worm’s  larva.  New strains of this parasite have been discovered that are found even in birds and crocodiles.

Toxoplasma gondii is a parasite that is the second leading cause of deaths attributed to foodborne illness in the United States.  It is one of the more common parasites in the world and affects about 1/3rd of the human population.   The parasite goes to the brain and forms cysts.  Laboratory rats affected by toxoplasma gondii loose their innate fear of cat urine odor and the males begin to produce more testosterone.

Hepatitis E is a liver disease caused by a virus transmitted by fecal contamination in water or food supplies.

Chemical Additives

Without food science and the shortcuts taken by Big Food and Big Pharma corporations, we could not sustain our present standard of living, nor feed ourselves- our masses as we do.   Not too long ago, almost all edible foods came from farms.  Today’s food however is largely produced in factories.  This processed factory food is chock full of questionable chemicals and additives.  Be assured that most of these additives are safe from a chemist’s perspective.  Intermittently however, new research uncovers dangers and unintended consequences associated with ingestion of these ‘safe’ food additives.

Sodium phosphate commonly encountered as approved STP (Sodium Tripolyphosphate) allows meat to hold more water.  This is good for the seller who pumps this stuff into meat and bad for the buyer who must purchase meat by weight.  To be fair, phosphates do help extend the shelf life of meat and dairy products like cheese by restricting the development of rancidity.  Phosphates are under suspicion however of increasing the risk of kidney disease, high blood pressure and heart disease.

Sodium Lactate also increases meat shelf life and can be expected to benefit color and taste.

Sodium Erythorbate, Erythorbic Acid and Sodium Isoascorbate are added to meat to preserve its color.   Keeping meat pink is a big thing; carbon monoxide gas is also used for this purpose as were sodium or potassium nitrites before the 1970’s.

Monosodium Glutamate (MSG) is an amino acid that makes meat and other food taste better.   It allows companies to perhaps put less real meat into packaged food.   Irregardless to brain damage caused to mice, baby- food makers of the 1960s put MSG into those little jars to influence the taste buds of parents.

Potassium Sorbate and Sorbic Acid inhibit mold growth on jerky, sausages, cheese, syrup & jelly.

Sodium Citrate which is a crystalline salt derived from citric acid fermentation or by the neutralization of citric acid with sodium hydroxide.  It’s been recently approved for use in meat products as a preservative where it slows spoilage from microorganisms.  Salty and tart in taste – it maybe used to flavor soft drinks and juices or be employed as an emulsifier.

Hydrolyzed vegetable proteins are used as Meat Flavor Intensifiers (MFI)  and boost or increase the meaty flavor of meat items, gravies, and sauces.

Ractopamine hydrochlorid  is not a chemical added to meat.  Rather it is a growth enhancer, fed to livestock, which increases profits by requiring less feed.  Quickly grown cattle fed this growth enhancer develop lean meat.  Chickens and turkeys fed stuff like this often develop over-sized hearts, kidneys and livers, and grow so fast and get so heavy that they become immobile and cannot carry their own weight.  Cattle and pigs fed a diet of ractopamine have developed abnormal lameness, bloat, breathing disorders and hoof disorders.   Approved in countries like the U.S., Canada, Mexico, Japan and S. Korea – ractopamine hydrochlorid enhanced meats are outlawed in the EU, China and Russia.

Transglutaminase (TG or TGase) is an enzyme that bonds protein molecules together.   First identified in 1959, it took another 30 years to find an economical source and exploit this ‘meat glue’.  “With meat glue you can glue any protein to any protein”.  “Gluing chicken skin to salmon works quite well….. and will actually protect the outside of the salmon from overcooking”.  <Frankensteined meat> 

Saltpeter can refer to several separate substances, most of which were strategic materials for making propellants and explosives in the 18th & 19th centuries.   Sodium nitrate (NaNO3) is the compound most usually identified as a meat preservative, but also potassium nitrate and magnesium nitrate to lesser degrees.   While regular table salt (NaCl) kills many bacteria like salmonella below 3% solution, much higher concentrations might be needed needed to kill other types of bacteria.   A concentration of about 20% salt soaked into meat would be required to make meat safe from most every type of microbe.   Meat that salty is not palatable.  Somewhere back in time before the Romans, people noted that salt from certain mines preserved meat better, retained its color and made it taste better.  Eventually traces of nitrate (saltpeter) were identified within that or those popular mined salt(s).  The nefarious Clostridium botulinum bacterium was identified in 1895.  Thereabouts it was determined that nitrate salts kill or inhibit the botulism causing bacteria.  Since saltpeter also benefits color retention and imparts a desirable flavor we have been using nitrate meat preservatives every since; up until the 1999 that is.

The U.S. FDA has determined that nitrates are no longer allowed in commercially packed meats, while nitrites are to a limited small degree (for dry cured uncooked products like jerky).  Nitrates and nitrites differ by one oxygen atom.  Ammonia is released into the soil by the decomposition of organic matter, and it oxidizes to form a nitrate or nitrite.    Nitrates themselves are relatively inert and enzymes in the human body convert them into nitrites anyway.  Some vegetables we eat daily are loaded with nitrates, containing far more nitrates that might be encountered in cured meats.  Some athletes might drink nitrate rich beet juice to enhance physical performance.   Nitrites can turn into useful nitrous oxide by losing an oxygen atom or into dangerous nitrosamines, which can be created by high heat cooking.  In the 1970s several studies showed correlations between nitrosamines and cancer in rats.  Since that time, nitrates in curing salts have been studied to an exhaustive degree.  The verdict is that nitrates and nitrites are not carcinogenic.  Apparently nitrosamine formation can be inhibited by ascorbic acid.  Since refrigeration is fairly ever-present today, there no sense in risking the possibility of someone creating nitrosamines by overcooking -uncooked nitrate cured meat.   Individuals wishing to hard cure meat by traditional means can still buy premixed ‘salt cures’ containing either nitrites or nitrates or both.   “Prague powder” is one such cure that is still sold after being invented 80 years ago.

USDA Ham and Food Saftey information.

Smoke

There are two widely separated forms of meat smoking.   The old way of smoking for long term preservation – is now referred to as “cold smoking”.   The new and widely spreading fad or form of meat smoking encountered these days is called “hot smoking”.

Hot smoking implies drenching meat in humid, flavorful smoke while simultaneously cooking the meat.   Temperatures between 130 and 210 deg F are required for hot smoking.  Since the cheaper and relatively tough cuts of meat are used in this process, the cooking is done slowly; taking a long time under moist heat to breakdown and soften the cartilage or gristle (collagen).    Done correctly those tough cuts become very tender to chew.   Hardwoods like oak, hickory, apple and cherry produce the most flavorful smoke.   Depending upon the fuel used to create cooking heat (wood fire, propane, gas, electric) the smoke might be generated by pellets or moistened wood chips.   Hot smoking is purely concerned with the art and science of cooking delicious, flavorful meat.   It does not impart a preservative effect upon the meat.

Cold smoking has been going on for thousands of years, and for more practical reasons too when considering the historical lack of refrigeration.   Wood smoke imparts preservative creosote to the meat that discourages insects and microorganisms alike.  Wood smoke flavor in an aged hard cured ham or bacon might be intense, but still of a secondary nature when compared to the typical saltiness of that same dehydrated meat.   “Virginia hams” were and still are famous for their flavor but these are often so salty that they need to be soaked and rinsed for 3 days to get the salt out.

Speaking of Virginia hams, Martha Washington (wife of the first American president) was famous for hers.  The plantation at Mount Vernon was typical for plantations of the period.   In addition to a large number of working residents to feed daily, guest and foreign dignitaries were always dropping in for visits.   Martha reportedly set a good table.  She also took pride in her hams, oversaw their curing process and shipped many away as gifts, some across the ocean.   Two hundred years ago working plantations like this had crews to maintain large continually smoking smokehouses, which were packed with beef, pork, mutton, ducks, geese, fish and anything else they could find.

Famous uncooked, hard cured, smoked Virginia hams are available for purchase.   These and some others like them are intended to be cooked, however some even more prominent European hard cured hams are usually eaten raw and are still allowed to be imported to the U.S.  (Ardennes Ham from Belgium, Jamon Iberico & Jamon Serrano from Spain, Prosciutto from Italy,  Westphalian Ham from Germany and sometimes York Ham from England – for example).

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I am neither a chemist, physician nor an authority on the safety of consuming uncooked meats.   All I can do is observe and realize that decisions made while preserving meat in traditional ways, do carry some risk and should not be made lightly.

Somehow this particular post took a detour and became somewhat longish.   The title will be truncated from “Curing meats & Tanning hides” to what you see now.   The last image from the post preceding this one featured a tiny homemade cold smoking apparatus featuring a venturi.  The background of that fabricated image features a (lost) drawing of an industrial smokehouse, the type of which might have been found in any city of size, before artificial refrigeration was realized.   Wood smoke was also used to preserve leather, a trick American ‘Indians’ were fond of.  Rawhide and leather though, are fodder for a future post

 

Hot Stuff 3 – Rocket stoves to meat smoking

Pertinent

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Versions of the “rocket stove” principle have been manufactured for about 90 years, so the concept must be older.  Above is a cheap and quick example of a rocket stove made with about seven tin cans.  The barrier between the inside chimney of small cans and the outside layer of large ones, is insulated with sifted wood ashes.  Rocket stoves are efficient for cooking because they burn hot and use very little fuel.  The “rocket” name undoubtedly stems from the vigorous manner in which air, flame and smoke are all drawn into the chimney.

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For free standing little cook stoves and water heaters the optimum chimney height might be a little less than three times whatever inside diameter is actually chosen for the chimney.   These proportions seem to engender the best draft.

Once a fire has been ignited it takes a few minutes for the stove to become normalized.  Once hot and working correctly these little stoves consume almost all the volatiles in smoke and leave little pollution.   Using just dry twigs these stoves are capable of reaching 1,600 – 1,700°F (926°C).    * That’s a temp high enough to melt tin, lead, zinc, antimony, magnesium, aluminum and lava – but not silver, gold or copper.

Iron stoves or the ‘tinplate’ steel found in a soup can will not stand up to long term heat of this degree because of the accelerated rate of oxidization.   For this reason a stainless steel, ceramic or refractory version would be desirable for stove longevity.

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Slick stoves working upon the rocket principle have been made with cinder blocks and stacked bricks.  This link is to a rocket stove manufactured in China.  These are practical products but seem a bit costly.

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A long lasting cementatious rocket stove can easily be made at home.   This image (idea robbed from a video) depicts creating a mold from plastic sewer pie and a 5 gallon plastic bucket.   Yes the mold could be filled with plain cement but a refractory mix would be more desirable.   A concrete rocket stove would conduct heat and become hot to the touch and would also be heavy to move.   A stove cast of proper refractory would be lighter weight and insulated, allowing desirable higher heat inside the chimney.

Opinions and examples of refractory mixes vary widely.   Perlite and vermiculite are frequently listed as light weight insulating ingredients in refractory mixes.  If the intended function is not too demanding, wood sawdust or peat moss might substitute as the light weight, insulating ingredient.  Perlite is a volcanic glass that has been ‘puffed up’ like popcorn (with the help of escaping steam when it was created).   You’ll frequently find little individual white beads of perlite mixed in with commercial potting soils, or sold in bulk at plant nurseries as a soil amendment.  Exfoliated vermiculite possesses many of the same qualities as perlite.   Fireclay is an ingredient used in the refractory of brick, ceramic and glass kilns, because few other building materials can repeatedly withstand such high working temperatures.   An easy to remember recipe for an adequate refractory mixture would be four equal parts each of sand, Portland cement, fireclay and perlite (or vermiculite).  Those proportions could be tweaked a bit to reduce sand and cement (1.5 sand, 1.5 cement, 2 fireclay, 2 perlite).

When casting a mixture like this it is important to use as little water as feasible to ensure the strength of the concrete (refractory).  Do not forget to allow adequate space at the bottom for insulation of the chimney and remember to tamp this first, with a stick, before filling the remainder of the mold.   A wire skeleton or armature of some sort would greatly enhance the long term resilience of such a cast.

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Two centuries or more ago, the chimney in the center principle was being exploited by expensive handmade self heating teapots known as samovars.   Manufactured portable utensils for heating or sanitizing water outdoors began to be seen in numbers for the first time however during WWII, when the New Zealand Army issued their soldiers with mess kits containing jacketed kettles.   ‘Storm kettles’ or ‘volcano kettles’ work well in windy or rainy weather.  Fuel from twigs to straw to buffalo chips can be found almost anywhere and cost nothing.

Not commonly found in American sporting goods stores, these kettles are made by several little companies and are produced in either aluminum or stainless steel versions.   Rather than pack into the woods a stove that requires special fuel (sterno, denatured alcohol, hexamine tablets, paraffin wax, kerosene or  naphtha (white gas)) it seems more logical to carry one that simply uses fuel which can be picked up from the ground.

Thermette:  Ghillie-kettle:  Eydonkettle:  Kellykettle

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For some time now some people have been using a larger form of the rocket stove, known as a “mass heater”, to warm the home.  In this case the exhaust from the chimney is captured and turned downward, then circulated through a wall, the floor or a banco (bench).   The masonry in the wall, floor or bench acts as a thermal mass or heat sink that collects the heat and releases it slowly.  So from the illustration above an oil drum or other metal hood accomplishes the first heat exchange to the room’s atmosphere.  Any remaining heat is ideally captured by a thermal mass before the exhaust is finally released to the outdoors.

A few examples of these thermal mass heaters are found almost all over the world.  It would be very feasible to pre-heat water for the home by wrapping a water line around a rocket stove’s chimney.   Potential construction concerns for building a mass heater of this type include ensuring that the draw of the stove is sufficient to push exhaust through a long ductwork.  One critical dimension is the distance between the top of the chimney and the hood (drum).   Some people brag that the amount of firewood needed to warm their house was reduced by 75% after resorting to a ‘mass heater’.   One should consider however the extra time spent splitting wood into pieces small enough to feed into this stove, and the extra attention probably required to keep the (fast burning) stove continually fed.   Depending on size it may take several hours to several days to equalize the thermal mass, so hopefully in the meantime the house would be equipped with an auxiliary source of heat.

 

Added 7/27/2016

The rocket stove mass heater takes its idea from the much older masonry stoves and or ceramic stoves of Europe and Russia.  Usually constructed of brick and covered in tile these often massive heating appliances are at least one thousand years old in design principle yet are still “greener” and more efficient than modern heating alternatives. 

The typical “tulikivi” (Finnish), “kachelöfen” (German), “kakelugn” (Swedish) or “pechka” (Russian) oven stoves only need to be fired about twice a day to provide a continuous 24 hour heat.  In some homes the people sleep on them, or may also bake with them.   When designed well they burn very hot and therefore leave little creosote buildup behind.   Inside the fire’s exhaust must furl around a labyrinth of baffles before it can escape, providing time and surface area for energy transfer.

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In the last century or so of newer building construction, massive masonry heaters like these were usually replaced with much smaller coal, oil or natural gas burning alternatives.   

The cast iron wood cookstove became a favored house heating appliance in America homes between the 1870s and the 1920s.  They were advertised in newspapers and mail order catalogues and were manufactured by a host of different companies like ACME, Acorn, Garland, Majestic, Monarch, Peninsular, Pilgrim and Sterling.  These wood stoves or ranges could act as energy centers perhaps for the whole house and they supposedly baked a better loaf of bread than any modern gas or electrical counterpart.   Different models came with different options including ornate chrome (probably nickel) trim, hot water reservoirs, foot latch, thermometers, broiler drawers and secondary warming ovens.   Cooking on such a stove could require much patience to establish the fire, because in addition to the firebox some models came with an adjustable main draft regulator, check draft regulator, stove pipe damper and an auxiliary damper.  It was standard practice for a housewife to keep a stock pot on the back of the stove, where she put leftover scraps of meat and bone.   Comfortable and desirable in the winter – these stoves could become beast to cook with however on hot summer days. 

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 Pertinent links-

Tile stoves

Masonry heaters

New wood stove

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After reconsideration the project on the right above will be redesigned from an “L” shape to a “J” shape, to allow fuel to be fed from the vertical axis.   Sheet metal screws will be reversed so that they can be removed from the inside.  After that cans are to be wrapped in plastic food wrap and a chicken wire armature will be wrapped around the cans – suspended about an inch away.   After that a refractory mix will be slathered over the armature to a depth of about 2 inches.    Some of the metal cans will be too hard to remove initially, until years afterwards when the rust can then be pulled from the refractory easily.

(Slideshow below added August 2016)

This slideshow requires JavaScript.

 

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The image above is a little incongruous with the topic of rocket stoves, but since it is related to fire and cooking and was available, it is included now.  Methods for cold meat smoking are diverse and numerous.  This image depicts a homemade variation of a commercial product which blows a steady stream of wood smoke into a meat holding chamber.   The main feature is the venturi which in this case is powered by a tiny air pump (like one used to aerate a fish aquarium).  The can below the homemade copper venturi needs a lid that will open and close; to insert wood chips or remove ashes.  The can needs some holes in its bottom so that combustion air can be drawn up through the smoldering woodchips.  Twelve to sixteen ounces of (hardwood) wood chips should provide about three hours of smoke.

There is not enough time and space left in this installment to adequately explain the important details of meat curing.   Remember that the wealthier half of civilization has only possessed artificial refrigeration for the last century or less.   Salt and smoke dehydrate -bloody raw meat.  Salt and smoke and cold weather have historically been the preferred tools for preserving meat by protecting it from bacterial spoilage.  Traditionally, smokehouses worked continually around the clock and pretty much throughout the year.  It is recognized by some that today’s commercial hams and bacons will putrefy long before they should (had they been properly cured and smoked by traditional methods rather than by quick methods).

In 1832 it was discovered that pyroligneous acid from creosote in wood smoke was the antiseptic preservative which protected meat.  Today commercial meat processors commonly inject into boned meat, salt, nitrites, nitrates and sulfides.  Before slaughter the animal may have been fed antibiotics, steroids or additives like ractopamine hydrochlorid.  About 70% of all chicken and beef sold in the U.S. and Canada is actually treated with carbon monoxide before you buy it.   The best way to tenderize meat without resorting to chemicals, is to cook it slowly.  Nowadays the best reason for treating meat to wood smoke (longer is better) is for the taste.

A Primer on Explosives

It has been repeated so often that it is now accepted as fact that the Chinese invented black powder around the 9th century AD.   This may be the truth or it may be a myth perpetuated after Marco Polo wrote memoirs of his 13th century experience in the East.   There is actually some evidence to suggest that gunpowder may have actually originated in Greece or India.  It is not disputed that the Chinese were apparently the first to show significant progress in the refinement of black powder and the development of fireworks, the first to propel rockets and the first to attempt to intimidate enemies with explosives.

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Introduced in 1961 the RPG-7 imaged above shares several admirable qualities with other Russian weapon designs; namely it is cheap, uncomplicated, efficient and rugged.   This rocket grenade launcher is encountered around the world and has been involved in most every armed conflict of any consequence for the last 40 or 50 years.  In Somalia or Iraq such a weapon might be acquired for about $200 and additional rockets might cost about $20 to $30 apiece.   In black markets of other parts of the world an old and worn RPG-7 might command about $1,000.  A standard HEAT (High Explosive Anti Tank) rocket as shown in this image would be obsolete and ineffective against modern tank armor but still devastating against softer targets.  Fragmentation grenades and small thermobaric warheads are also available for this launcher.   In the image the solid booster charge, solid rocket propellant and the unlabeled conically shaped HEAT warhead are all “explosive” or are potentially detonate-able although the first two chemical compounds merely deflagrate in a controlled manner.

Deflagration vs. Detonation

For a chemical to be considered explosive it must rapidly form gases and heat and exhibit the ability to be initiated by shock or by heat.  Chemical explosions are simply accelerated rates of chemical decomposition.   A campfire is an example of chemical decomposition as is gunpowder burning in a shotgun barrel.  Gunpowder, fireworks and air-fuel mixtures in internal combustion engines are “low explosives” and examples of “deflagration”.    Deflagration (from Latin – “to burn down”) is a rapid but subsonic (342 m/sec or less, 1,126 ft /sec or less) decomposition where a combustible and an oxidant are reacting at the molecular surface area, called a “flame front”.   The fake looking explosions in most Hollywood movies are examples of deflagration; where pyrotechnic stunt coordinators make big yellow-orange fireballs by setting off containers of gasoline.   In contrast, “high explosives” exhibit detonation.   Detonation is a supersonic reaction where a “shock front” rather than a flame front, travels through the explosive.   Detonations propagate through shock compression and can reach speeds of up to 9,000 meters/sec (29,527 ft. /sec).

* For comparison the fastest bullets or shells from rifles or cannons have a top speed of about 4,000 feet/sec (1,219 m/s).  Although the unconfined propellants do not deflagrate that fast, the buildup of pressure confined, accelerates the projectiles to that speed. 

* If detonated at the same instant that a fast bullet was fired from a rifle, a six mile length of primer cord filled with an explosive like RDX (which has a high detonation velocity),  would have vanished in its entirety before the bullet had gone one mile.  

* Without the confinement of a barrel and closed breach, a loose rifle or pistol cartridge when tossed into a fire – would pop like a child’s firecracker and be about as dangerous.  The brass case might split, some coals will be thrown around and the bullet may or may not bounce a few feet.

Shockwave

The caption or information included in the following video explains that it displays the destruction or disposal of a solid fuel rocket motor from a retired ballistic missile.  The caption claims that 38,000 lbs of HD 1.1 propellant are detonated.   HD 1.1 (Hazard Division 1.1) implies a nitramine-based explosive like RMX or HMX (both are commonly used for solid rocket fuels as well as components in the lion’s share of modern military grade plastic explosives used by the US and GB).

Huge Explosion and Shockwave

The problem with this video is that at this level of camera zoom, the supersonic shockwave or blast wave passes too quickly to be seen.  What can be seen and what is erroneously referred to as a shockwave is actually the transonic sound wave.  The camera was filming from about a mile away, which can be verified by the fact that the shadow and sound (which travels about 1,125 fps) took about 5 seconds to reach the camera.

This following ho-hum video, appears to be a clip from a TV show.   Some impression of shockwave is captured by high speed cameras.

Huge Shockwave Captured at High-Speed | Military.com 

More shockwave information: http://physics.info/shock/

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Brisance, Stability & Sensitivity

    Brisance is a French word meaning “to break”.   The brisance or the shattering effect of an explosive is proportional to its speed of decomposition but is not a total measure of the compound’s work capacity.  Relative brisance between explosives might be determined by field testing or sand crush test.   Knowledge of relative brisance is useful to bomb and fragmenting shell design engineers or to Army engineers preparing to destroy bridges, bunkers or other structures.

Stability refers to the ability of an explosive to be stored without deterioration.  There is a large variation in the stability of various explosive chemical compounds.   Fulminate of mercury as used in the priming compounds of rifle or cannon cartridges might be considered to have a good stability.   A high percentage of mercury fulminate primed rifle cartridges from the WWI era might be expected to perform (if they were stored well) even though they are now approaching 100 years in age.   On the other hand, long stored nitroglycerin has a reputation for separating from the other constituents in dynamite.  Such old dynamite becomes “unstable” because it deteriorates; the nitroglycerin collects as a liquid and becomes dangerously “sensitive” again.   TNP (Trinitriphenol or picric acid) which was once used as a primary explosive in naval and land artillery shells prior to WWI, eventually tended to corrode the metal shell casing it was housed in and created new and dangerously sensitive chemicals.

Heat, friction and shock test are preformed on explosive compounds to determine their sensitivity rating.  Actually the scale used to gauge the relative sensitivity of different explosive compounds is called the “Figure of Insensitivity”.   For many years this scale was based upon the sensitivity of TNT which is very insensitive – with a rating of 100.  After the creation of faster explosives in WWII, TNT was supplanted as the most common comparison gauge by the more sensitive RDX (with a rating of 80).

* Invented way back in 1863, TNT (or trinitrotoluene) was so insensitive that it was a challenge to make it detonate.  It was used as a yellow paint pigment for 40 years before it finally saw use in munitions.  It was notorously toxic for factory workers to handle and still being manufactured today. 

It is useful to understand that the blasting agents which provide the horsepower of an explosion are seldom if ever used alone and that a chain (or train) of reactions is usually necessary to produce the desired blast.   Common explosives like dynamite, TNT, and C4 are so insensitive and safe to handle that they require a substantial physical shock to set them off.   The first stage in an explosive train is a small and sensitive “primary explosive”.   Once stimulated the less sensitive “secondary explosive” might be the end of a train or the stimulant to set off an even more insensitive third stage.  This final or tertiary stage provides the real horsepower in such a chain, and might consist of a very insensitive blasting agent like a compound of horse manure and diesel fuel or ANFO (Ammonium Nitrate and Fuel Oil).   In essence a lowly firecracker can be the initial stage of an explosive chain leading up to the eventual detonation of the mightiest thermonuclear device.

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Igniters, Blasting Caps & Detonators

Commercial and military detonators might comprise a little explosive train in their own right, containing perhaps three separate compounds.  The most common primary explosives used in today’s blasting caps & detonators are DDNP (Diazodinitrophenol), mercury fulminate, lead azide, lead styphnate and tetryl (until recently).   Potassium chlorate and potassium perchlorate were once used in explosive primers and detonators.  Today’s blasting caps might house small – less sensitive secondary charges of PETN or RDX perhaps.

* Compounds like nitroglycerin and silver fulminate are simply too sensitive to safely handle.   Other compounds can be used as primary explosives but are seldom used in modern detonators for various reasons.  These would include:  acetone peroxide, ammonium permanganate, azo-clathrates, copper acetylide, HMTD, lead picrate, nitrogen trichloride, nitrogen triiodide, silver azide, silver acetylide, sodium azide, tetacene, tetrazoles and triperoxide.      

* Apparently the first blasting cap was realized in 1745 and consisted of black powder which was set off by a spark from a Leyden jar.   Later in 1750 Benjamin Franklin created a better blasting cap by stuffing two parallel wires and black powder into a rolled paper tube.  The first glowing “hot wire” detonator appeared in 1822.  The first pyrotechnic fuse blasting cap was created in 1863 by Alfred Nobel.  It used a burning fuse and mercury fulminate to detonate his relatively insensitive and patented, nitroglycerine based mining explosives.   Five years later someone else invented the first electrical blasting cap capable of detonating dynamite (this combined mercury fulminate and a spark gap igniter).   

* Today pyrotechnic fuse and fuse caps (more modern metal tube equivalents of Nobel’s original wood tube) are becoming rare because older explosives like dynamite and gelignite (blasting gelatin) have largely been displaced by more modern and usually cheaper alternatives that might also leave less noxious fumes behind after a blast.  Even electrical blasting caps are becoming less common for certain types of blasting; the wires are being replaced with little plastic air tubes.  Avoiding radio waves and static electricity, these tubes transfer shock to the primary explosive using air pressure. 

Military detonators are usually a bit stronger than their commercial counterparts.   Today #6 and #8 caps are the only commercial blasting caps mentioned.  A # 8 cap is traditionally about twice as powerful as # 6 and would be used for initiating less sensitive explosives.  There is no such thing as a commercial # 4 blasting cap, but had it existed it would have reflected the power of a cap containing .4 grams of mercury fulminate.  Cap  numbers less than 6 are apparently not made and cap numbers stronger than 8 don’t exist or have no convention standards.  There may have been a time when mercury fulminate was the only substance used in blasting caps but before long potassium chlorate began being mixed with it.  Potassium chlorate was cheaper than and enhanced the power of the mercury fulminate.  A traditional # 6 blasting cap of yesteryear contained .2 grams of 80/20 primary (fulminate/chlorate mix) and .4 grams of a booster like PETN.  A traditional No. 8 cap would have differed by housing twice the PETN.   Modern # 8 caps have increased substantially in power depending on the source and have become the common types, but there is a lot of variance in what is termed a # 8 detonator.  A “US Army (Engineer’s) Special Blasting Cap” or “Military No. 8” for example might contain as much as 13.5 grams of PETN or RDX.

A matchhead or firehead electrical blasting cap uses an electrical match that sits in a pyrotechnic ignition mix in the butt of the cap.  An electric match is nothing more than a thin wire with a dollop of substance like dried red phosphorus attached to it.  It is a wire that gets hot and basically ignites the equivalent of a ‘kitchen match’ and starts the explosives train.   Only 3 volts from 2 flashlight batteries is required to set off the simple electric matches or ‘engine starters’ of solid propellant toy rockets.   Multiple exploding bridgewire detonators are generally used to uniformly initiate the primary stage of a nuclear weapon.   In effect a high capacity electrical discharge vaporizes each very thin bridgewire which in turn initiates a shockwave that simulates the chemical reaction.  The Germans were the first to use this type of detonator with their demolition charges in WWII.

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*Explosions that detonate or deflagrate produce a lot of gas.  A mole of a substance is its mass in grams, as determined by the atomic numbers of its constituents and at standard temperature and atmospheric pressure a mole of any kind of gas occupies the same 22.4 liters of volume.   Using nitroglycerine as an example: one mole of nitroglycerine (@ standard atmospheric pressure) produces about 7.25 moles or 162.4 liters of gas.  One gram of nitroglycerine (about the size of a pencil eraser) would expand enough to fill a 43 gallon container with gas after decomposition.  The products in this example will be about 3 parts carbon dioxide, 2.5 parts water vapor, 1.5 parts nitrogen and 0.25 parts oxygen.

* Oxygen is essential for combustion and without it explosive chemical decompositions would go nowhere.   Oxygen is not a fuel, but an oxidant.   Concentrated sources of oxygen support rapid combustion.   Peroxides, nitrates, chlorates, perchlorates and dichromates all donate oxygen to combustion.

* Liquefied oxygen is about 840 times as dense as gaseous oxygen.  If spilled, liquid oxygen might soak into porous asphalt, charcoal, wood or petroleum products which then might become dangerously explosive for a short while.

Chemical jargon

Chlorates, perchlorates, nitrates, fulminates, permanganates and peroxides can be thought of as oxidizers with weak bonds and negative charges.

Chlorates are the salts of chloric acid (HClO3).  Combustibles like charcoal, certain metals, organic solvents, sawdust and sugar will easily deflagrate when mixed with a chlorate salt.  Many fireworks in the past were composed with mixtures of chlorates, with various combustibles providing different colors and effects.  In modern fireworks, more stable perchlorates have replaced chlorates as the oxidizer of choice.

Perchlorates are the salts derived from perchloric acid (HClO4), and they are often produced by the electrolysis of chloride salts.  Aside from pyrotechnics, perchlorates are also used in automotive airbags and as solid rocket fuel.  The Space Shuttle launches were powered by two solid rocket boosters that each held 350 metric tons of ammonium perchlorate.

–  The nitrate ion (NO-3) is formed when nitric acid and an alcohol are joined.  A nitrite (NO-2) is the salt of nitrous acid and not the same thing.  The molecular formula for nitrous acid is HNO2, while the formula for the much more significant nitric acid is HNO3.

–  Fulminates contain the relatively unstable fulminate ion (CNO-).

–  A permanganate is an oxidizing compound containing the manganate ion (MnO4-).

–  Peroxides are oxidizing compounds with the oxide anion (O2)-2 or single bonded oxygen to oxygen atom.   Hydrogen peroxide (H2O2) should be called hydrogen dioxide.   Barium peroxide is used in military “tracer” ammunition and in other pyrotechnics while triacetone triperoxide (or TATP) is a hard to detect.  TATP (or acetone peroxide) is easily produced, sensitive and fairly unstable but popular with terrorist like the would-be “shoe bomber” in 2001.  The shoe bomb had a dry TATP detonator along with PETN as the secondary explosive.   Perspiration made the fuse damp and the odor of several matches gave the imbecile’s intentions away.   The ‘hypergolic bipropellant’ of the remarkable WWII rocket-powered fighter aircraft (the Messerschmitt Me 163 Komet) was mixed from “C-Stoff” (a methane-hydrazine fuel) and a high test peroxide oxidizer called “T-Stoff”.   “Hypergolic” means that the propellant components spontaneously ignited when combined.  In field test and during the short carrier of the Me 163 during the war, several aircraft and many people were lost in explosions when these volatile components were handled.   When dealing with this rocket-plane, pilots & ground crew wore special nylon or rubberized clothing just to keep their flesh from being dissolved by these fuels.

Public Domain courtesy FBI

Public Domain
The Shoe Bomber’s Shoe

Nitramines are generally refer to newer and more chemically sophisticated compounds having bigger molecules, higher density, more of the hard to split covalent bonds and more energy packed into a given space.  While some of the best modern military grade explosives are nitramines, the benchmark for explosive speed and efficiency is still nitroglycerine – invented some 1.7 centuries ago.

– A binary explosive simply implies that two components are required to be combined but individually neither component is explosive.  The insensitive and very common blasting agent ANFO could almost be considered a binary explosive.   HELIX™ High Energy Liquid Explosive Binary Energetic is also an example of a binary.

Reactive elements

In pure form the “alkali metals” (Li, Na, K, Rb, Cs & Fr) are reactive or can be potentially dangerous in their own right.   Lithium hydroxide (as stored) when converted to lithium deuteride is used as a fuel in hydrogen bombs.  Pure potassium (K) explodes when it touches water, while rubidium, caesium and francium get even more violent than that.   The alkali metals are rare, and are never found in a pure form in nature – because they are so reactive.   Sodium (Na) and potassium (K) chlorates, perchlorates, nitrates and permanganates are very prevalent in explosive compounds.   Another group of elements called the “alkali earth metals” (Be, Mg, Ca, Sr, Ba and Ra) are reactive, but not as much so as the alkali group.   Of these, manganese (Mg) is commonly mixed in explosives, calcium (Ca) in calcium carbide makes explosive acetylene gas and barium (Ba) has already been mentioned for its use in pyrotechnics and tracers.   Aluminum (Al) belongs to a separate group in the Periodic Table but it is also fairly reactive (which explains why it is never found as a pure form in nature).   Powdered aluminum is a common catalyst or additive, usually mixed into ammonium nitrate or other explosives to enhance the blast power.

*  Hydrogen (H) which is the lightest and most abundant element in the universe, does burn, and can be considered explosive (if exposed to a flame) in concentrations between 4% and 74% with the surrounding air.   Hydrogen can react spontaneously with fluorine and chlorine.  The main engine of a Space Shuttle burns oxygen and hydrogen.   At full power the flame from one of these engines, is invisible – or nearly so, because it emits light in the ultraviolet spectrum.  Checking a pipe for a hydrogen leak involves looking for an ultraviolet flame – as hydrogen combines with oxygen in the air.   Hydrogen fires are seldom as dangerous as gasoline fires.  In 1937 the famous Hindenburg blimp, which was full of hydrogen burst into flames as it approached its landing.  The visible flames of that disaster were the burning outside skin of the blimp.  The hydrogen gas however rose quickly, carrying the invisible ultraviolet flames with it.  The deaths that did occur were the result of falls or by burns from diesel fuel. 

Fluorine (element #9) is so extremely reactive and electronegative that almost all other elements including some of the noble metals and noble gases will form compounds with it.   Hydrofluoric acid was so dangerous that laboratory explosions killed “fluorine martyrs” (chemist) like flies in the 19th century and it took 74 years of concentrated effort just to isolate elemental fluorine.

Phosphorus (P) is a nonmetallic, very reactive element which has been used in many explosive munitions.  It is an additive to start fires and to create smoke.  It is or was used in kitchen matches, fireworks and in weaponized nerve agents.  This elusive element was discovered about four centuries ago when an alchemist dehydrated his own urine, and then noticed that it glowed in the dark.   In WWI, phosphorus was employed on incendiary ammunition against blimps and aircraft.   In WWII phosphorus bombs were dropped on London to start fires while other phosphorus munitions were used to ignite aircraft, tanks and other vehicles, for smokescreens and for anti-personnel mortar rounds.

* A modern incendiary bomb is likely to employ a thermite mixture of aluminum and ferric oxide. 

Black powder

Throughout its history and up until recent times there was no “black powder”, but simply “gunpowder”.    Modern nitrocellulose based “smokeless powders” have become regular “gunpowder” in today’s parlance while the term “black powder” now invokes the old charcoal, sulfur and saltpeter propellant.   In the previous century the term “flash powder” might have denoted the finely ground and very volatile FFFFFg gunpowder used by photographers to generate more light exposure for pictures.   While originally, firecrackers were made with black powder; today’s firecrackers are usually constructed using a faster burning compound called ‘flash powder’ (with magnesium or aluminum powder and a potassium chlorate or perchlorate oxidizer).

True black powder is messy because only about ½ of the material is burned.  It leaves behind a lot of unburned residue that quickly fouls a weapon.   Most new, so-called “primitive firearms” that are used today are never loaded with true black powder – but instead with a cleaner substitute having equivalent deflagration properties.  The main deficiency of black powder (or similar replacement) lies in its inability to drive a projectile past a certain speed.  Black powder has a relative detonation velocity of 1,312 fps.  Confined in a firearm, its pressure peaks almost instantly and starts to drop even before the projectile leaves the barrel.   In contrast the even slower burning smokeless propellants that replaced it in modern firearms, achieve higher projectile speeds because they produce more gas and continue to push and accelerate the bullet as it travels down the barrel.  Cramming more black powder into a black powder muzzle might speed a bullet up to 1,750 or 1,800 fps, unless the increased pressure ruptures the firearm’s breech beforehand.

In 1275 A.D. the standard recipe for black powder was 1 part charcoal and 1 part sulfur to 4 parts saltpeter (potassium nitrate or niter).   More ideal proportions have been determined to be around 13.5% charcoal, 11.5% sulfur and 75% saltpeter.  Charcoal is the fuel; sulfur the binding agent and saltpeter the oxidizer.  After firing black powder’s fouling or residue is corrosive and purportedly contains carbon and sulfur, potassium carbonate, potassium sulfate, potassium sulfide, potassium thiosulphate and potassium thiocynate.

Many a powder company has disappeared in a cloud of smoke, flame and noise during the crushing stage of black powder production.  Static electricity can easily ignite black powder.  In the manufacture of black powder, metal implements are avoided because they might cause sparks or build up static energy.  Before the process called “corning” was adopted, early black powders tended to separate or sift apart; making them inconsistent and possibly unreliable.  Corning was a process where water was added to the gunpowder and was then pressed out.  While still moist the propellant could either be pressed through a screen to make granules or left to dry as cake that was later crushed into small powder.  Using the corning process the final product became more homogonous and the separate ingredients were bonded in crystalline form.

Crushing the powder into smaller grains created more surface area particulate, more flame front and therefore faster burning. In the old days, black powder was graded in regards to its granule size, from 1F to 5F.   “Fg” powder would be used in something big, like a cannon.   “FFg” was intended for large bore shotguns and rifles.   “FFFg” was the common powder for most rifles.   “FFFFg” was fast powder for pistols and for flintlocks with flash-pans.   “FFFFFg” was rare and very fast and as mentioned, was occasionally used by early photographers to produce light in dark settings.

Although black powder is smoky and pokey, it is still getting the job done after a good 700 years of field testing, on land and at sea.  Every manner of big game including African elephant, rhino and Cape buffalo has been felled by it.  At range, in the right hands, black powder rifles have preformed respectably, even by today’s standards.   In front of witnesses a frontiersman once knocked an Indian brave from his horse from 1,538 yards away (later measured, 0.87 mi), using a 50-90 caliber Sharps.

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Another testament of black powder accuracy involves a British made sniper rifle used by the Confederacy during the Civil War.  The Whitworth rifle as designed by Sir Joseph Whitworth in 1856 employed a hexagon bore and a hexagon bullet of .45 caliber.  The Whitworth rifle was apparently accurate to well over 1,500 yards, but very expensive and the Confederacy only purchased a handful to issue to a few chosen snipers or skirmishers.   It seems that Yankee General John Sedgwick was unhorsed by a Whitworth during battle.  Sedgwick was rousting his troops who were hiding from sniper fire.  His famous last words were “They couldn’t hit an elephant at this distance” just before a fatal bullet fired from about 800 yards away, hit him square in the face.

A black powder firearm is a pretty crude weapon by today’s standards but in its simplicity lays a certain elegance and reliability.  Modern weapons require modern ammunition a source of ammunition is important.  If sources of modern ammunition run dry then the weapon becomes useless for either hunting or self defense.   Individuals that know how to reload ammunition might fare better for a while – until their source of nitrocellulose powders, primers and bullets runs out.  A survivalist with a black powder firearm however, with the know-how can mould his own bullets, make his own propellant and probably even make his own percussion caps if needed.   Making black powder propellant is hardly rocket science and sources of information on this subject abound.  The differences in proportions are not too critical. The best homemade gunpowder will probably be inferior to commercial powder but should work.  It should not be considered an act of anarchy or the abetting of terrorism to provide the interested reader with a recipe here.

* The following recipe is a combination of ideas from too separate books (“Special Forces – Guerrilla Warfare Manual” by Scott Wimberley and “The Poor Man’s James Bond” by Kurt Saxon).  The proportions of 6 parts potassium nitrate to 4 parts charcoal and 1 part sulfur would comprise a fine mixture.  If the units of measure were cups then this mix would produce about 4 pounds of propellant (perhaps ½ the measure would be more appropriate).  The different components should be ground separately into small powders before beginning.  Here the methods from the two books deviate.  In one example the three components are mixed with a little water (1 part water – or preferably a better solvent like whiskey or rubbing alcohol) and allowed to set up into a malleable paste. The other method involves using more water (3 parts), heating the mix slowly until small bubbles rise, then dumping the mix into a large quantity of alcohol (10 parts), stirring and allowing it to gestate for 5 minutes.   In the second method the water is not allowed to boil, any mixture attempting to dry along the sides of the container is carefully stirred back in to keep it moist and after the 5 minute dip in alcohol the excess fluids are strained and squeezed out through a cheese cloth.  In both methods the somewhat firm paste or cake is pressed through a screen to produce uniform granules.  The granules can be set on a tray or flat surface to dry out in the sun. The quicker it dries the more effective it will be (a role in which alcohol plays a part). One author advocated sprinkling in a little graphite (if available) at this stage; the granules swirled in a lidded plastic bowl like Tupperware® become rounded and uniform. 

The advance of chemical Explosives

There are some 800 uniquely identifiable explosive compounds but admittedly some of these are simply compounds of more basic explosives already on the list.  This post will end here but a follow-up or second part will explore some of the more noteworthy explosive compounds, including: nitrostarch, nitric acid, mercury fulminate, sliver fulminate, guncotton, nitrocellulose, nitroglycerin, dynamite, gelignite, ballistite, lead azide, cordite, picric acid (trinitriphenol or TNP), lyddite, TNT, significant mixtures of TNT with other agents, tetryl, PETN, semtex, DDNP, RDX or hexogen, HMX or octogen and CL-20

 

Fire

 

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For about three million years prehistoric man apparently had no means to initiate a fire.  Once acquired from nature, maintaining a continuous fire then likely became a critically important function for someone – in a family, tribe or group.   It is assumed that humankind didn’t acquire reliable fire making skills until eons later, somewhere around 7,000 BC.  Then, as mentioned in a previous post it took humans about three thousand years to advance from copper – to iron – smelting temperatures; an increase of only about 500° Celsius.

*  Advancements in the control of fire’s concentration and the increase of its heat were critical prerequisites to tool improvement and therefore also crucial to our cultural evolution.   Anthropologist and archaeologist then are categorizing mankind’s cultural progressions into partitions  (i.e. Old Stone age, Neolithic age, Bronze age, Iron age, Dark age, etc.)  indirectly  based upon his ability to control heat.  

The process of initiating a fire would remain difficult and inconvenient for another 8,800 years.   Before the invention of the phosphorous friction match two short centuries ago, cultured society’s best fire starting technologies were scarcely improvements upon or less tedious to perform than those used by wild aborigine contemporaries or enlightened prehistoric cave men.   A review of some of these archaic techniques follows.

Starting from scratch 

Early on, the most popular fire starting method seems to have been the fire drill.  In this friction method the drill is a shaft of wood spun by hand pressure.  Dissimilar woods are primarily chosen, usually a harder wood for the shaft and softer one for the plank.  Continued friction causes powder or dust to separate from the softer wood and become heated.

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In the image above a base plank is specially prepared with a notch to allow the tiny precious glowing ember of hot dust to fall out onto some tinder.  The person blows on the ember, creates a flame, and then adds more tinder and kindling – to make the flame grow.  The whole process appears easy enough, but in truth can be a significant chore.  With practice however an individual can make the process work in less than 60 seconds.  It’s a question experience, technique and good tinder.  The world’s record for getting a suitably hot coal with a hand-drill is 4.5 seconds.

Another ancient friction fire starting method is the wood plough.  Popular in Polynesian cultures, this method also requires careful selection of woods.  The base is usually a small tree trunk or staff of soft wood with a grove worn into it.  While the base is held immobile a plow of smaller diameter hardwood is draw back and fourth in the grove.  As with the fire drill, friction creates dust which turns into a hot ember, which is then dropped into some tinder.  Like the fire drill, the fire plow requires experience and steadily applied pressure to work.

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A method of primitive fire starting popular in Indonesia is the “bamboo fire saw”.  A short section of dry bamboo is split in half.  On one half-section a small notch is started with a knife.  The other half-section that is to be used for the sawing can be whittled down in size and one edge should be sharp.  In method “A” below, the saw is below the tinder and is held still by the body pressing it against a firm object.  The ember is caught in the tinder above.  In method “B” below, the position of the saw is reversed and it is held in the hand.  The ember falls onto the tinder below.

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A popular New Guinea variation of the bamboo fire saw utilizes a thin strand of bamboo or tough local vine as a rope saw.  The bamboo plank and tinder beneath are stood upon as the friction is applied.

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The bow drill is actually an adaptation of the fire drill / hand drill method.  This method is also ancient.  Egyptians were using this method while building their pyramids.  Most other civilizations that used the bow for archery probably learned to use it as a fire starting tool also.  This was the favored method of some American Indian tribes although they did not forget about the hand drill.  An archery bow will work for fire starting, but a bow for such a chore does not need to be so big.  In fact a small branch about 2 feet long, with a small curvature, is optimum.

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The same kind of bottom plank or fireboard  incorporated by the fire drill method is used.  Other acceptable fireboards are a pair of branches tied together, a branch that has a season split or a chunk of  dead and dried tree fungus

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The shaft or spindle can be shorter with a bow drill (usually somewhere between 10” and 5”).  A thin spindle of about 5/8” to ½” diameter is probably best.  Initially pointed for starting a new hole, the spindle thereafter is kept round.  A socket of wood or bone knuckle is held in the hand that applies downward pressure in the spindle.  Optimally the spindle is braced under the shin, below the knee, where it can be held steady and secure.  Since the friction and heat is wanted only at the fireboard end of the shaft, the other end which held by hand will benefit from a socket with lubrication or a hard insert to reduce friction.  If the socket is wood then a metal bottle cap or a small concave stone insert will reduce friction while allowing more pressure to be gradually applied.  The types of wood used for spindle and fireboard make a big difference.   Given the choices at a random location – only experimentation will tell.  Yucca and Elm rate highly but Maple and Pine do not.

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3 bow drill sockets

The Egyptian bow drill used several millennia ago was often a tiny affair.  One of its attributes was the fact that the spindle was attached to the string.  Extra coils of string were wrapped around the spindle (wrapped both directions from center).  This allowed better traction and control over the spindle.  The spindle was fastened either by the string passing through a hole in the spindle or by the tying of a simple clove hitch knot.  Someone skilled in its use can start a flame within 25 seconds, using a bow drill.  The world record in the late 1930’s for getting a flame with a bow drill was 7.5 seconds …

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Another old variation of the bow drill is the pump drill.  The pump drill would be only slightly more complicated to build than the bow drill.  Used correctly, the spindle can be kept in continual motion by the centrifugal force or inertia of the flywheel and rhythmic motion of the pumping hand.  Useful friction would only be exerted on the downward stroke however.

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Before the 19th century the most advanced means of initiating a fire was with a kit called a tinderboxThe tinderbox, typically made of metal usually contained a sharp piece of flint (rock), a hard piece of steel and tinder.   Tinder simply means some type of very combustible material.   Tinder can be anything from char cloth (linen or cotton cloth that has been pre-burned in a low oxygen environment) to spider webs, various plant fibers, termite dust, grass, pitch wood, bird’s nest, down, fungus, Spanish tree moss, paper from wasp or hornet’s nest, oakum, cotton balls dipped in Vaseline or lint taken from a clothes dryer.   Tinder needs to be dry, fibrous, fluffy, and highly ignitable.   Many materials can be masticated and crushed to make them more fibrous.   The fancier tinderboxes of the pre-match era often had a c-shaped or horse shoe shaped piece of metal to hold in one hand, while the flint rock was held in the other.   When struck together friction ignites tiny shavings of metal, not rock.

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In all these afore mentioned fire starting techniques the precious spark or glowing ember must be captured by the tinder and skillfully assisted with extra oxygen to create a flame.

A more modern equivalent to the old flint and steel combination is the Ferrocerium rod.  Typically found in cigarette lighter “flints”, wind-up toys that spark or in a welder’s striker; ferrocerium is a man made mix of cerium and iron.  This material is usually pushed by a spring, against an abrasive piece of moving steel to create sparks.  As with the old flint and steel method, friction ignites tiny shavings of metal.  In this situation however the iron in ferrocerium burns, not the harder steel.  Cerium’s low temperature pyrophoricity is responsible for the easy sparking.  A modern survival kit might contain a single rod of ferrocerium as a fire starter.  It’s resilient to damage by water and reliable.  Better yet, a survival kit might include a magnesium fire starter.  Shavings of magnesium are scraped off into a little pile (already atop paper or other tinder).  The sparks are then scratched off the attached ferro-cerium rod, onto the magnesium flakes, which should then burst into flame.

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* A little match history

It took humankind at least nine thousand years of trial & error, to progress from hand or bow drills, to fire starters as instantaneous as kitchen matches & butane cigarette lighters.  Yet we modern people causally dismiss matches and lighters as being very simple devices.

In 1669 Hamburg Germany, an alchemist was trying to convert some of “life’s essence” into gold.  He took some of his own urine, let it rot, then boiled it down to a paste, then cooked it some more—letting the vapors travel through water.  What he got was a waxy substance that glowed in the dark (ammonia sodium hydrogen phosphate).  Two years later the Irishman physicist Robert Boyle (Boyle’s Law) rubs this newfound phosphorus against some sulfur and creates a flame.  Boyle did not exploit his opportunity to invent the friction match.  Mankind was to wait another 1.5 centuries before finding an easier way to start a fire.

Along came an English apothecary and chemist in 1827.  He invents a functional but impractical match called the “Prometheus”.  This was a wood splinter with a potassium chlorate head placed next to a tiny glass bead of sulfuric acid, then rolled in paper.  A person used tweezers or a bite with the teeth to break the glass and set off the flame.  More importantly, our apothecary later sticks a mixture of starch, gum Arabic, antimony sulfide and potassium chlorate onto a stick and lets it dry.  This invention he calls a “Congreve”, named after an officer who had introduced War Rockets to the British arsenal.  Large rockets (16’ long) that could rise 9,000 feet in the sky and which sprouted great flames (some were used against Fort McHenry- Baltimore harbor, in the War of 1812).  Our English chemist and friction match inventor did sell a few matches but he did not get rich.  Another Englishman exploited the commercial market for these matches, and renamed them “Lucifer s”.  They became very popular with smokers, but stank.   In 1830 a French chemist created a match that did not stink, using white phosphorous which was highly reactive and toxic.

During the next 50 years large match factories were created that mostly exploited the cheap labor of children, young girls and women.  “Phossy Jaw” was a famous ailment caused by inhalation of white and yellow phosphorus vapors in the match factories and often led to death.  The English “Suffragette Movement” and a defining moment in trade union history started with women striking against conditions and hazards of the match factories, in the Bow district of London.

In 1855 a Swede created the first safety match, using less dangerous red phosphorus and ignitable only on the box.  In 1889 the first matchbook matches were invented and were called “flexibles”.

By 1910 the Diamond Match Co. patented the first nonpoisonous match, using sequisulfide of phosphorous.  Asked by President Taft to release their patent for the good of mankind, Diamond Match did in 1911.   A century later the once common strike anywhere type of kitchen match has become rare in the US today.

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More modern “primitive” fire starting methods

Everyone probably knows that by using a magnifying glass, energy from sunlight can be concentrated enough to start a fire.  Without a quality lens and the cooperation of good sunlight thought, even this task is easier said than done.

A ray of light passing through the center of a thin lens keeps its original direction.  A ray that strikes anywhere else is bent. The amount a light ray is bent increases with its distance from the center of the lens.  A magnifying glass is actually a double-convex lens.  It can gather the energy from a broad area and concentrate it into a smaller area.  The focal point or hot spot is where parallel light rays converge (cross) along the principle axis of the lens.

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Dust and scratches or imperfections of the lens will diffract the light and lessen the practicality of this fire starting method.   Plastic or toy magnifying lenses generally diffract, diffuse, disperse or scatter so much light that they are useless for starting flames.  One is not likely to have or to run across a magnifying lens in an emergency situation.  Other types of lenses might be available however, and might be drafted into making an improvised double-convex lens.   Glass lenses can be salvaged from eyewear, cameras, binoculars, and telescopes.  The first two lens shape a & b in the following image, bends light in a way that’s unbeneficial to fire starting.  A pair of lenses with the shape a, back to back however might adequately mimic a double-convex lens.  The last two lens shapes e & f are the type normally found in eyeglasses.

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A drop of water placed on the back or inside of lens type e or f, will produce a temporary double-convex shape.  The surface tension of the water droplet should produce the opposing convex surface.  It takes a very steady hand to find the optimum focal point and to hold eyewear and water still; long enough to initiate a flame.  Not all eyewear is created equal so the vision prescription will actually be a factor in any success.

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Another clever idea for making a fire in an emergency involves the simple clear plastic sandwich “baggie.  One fills the baggie with water, and then twists the contents into a bubble or sphere.  With this makeshift double convex lens, one again needs to focus the hot point upon the tinder and hold it steady, long enough for the sun to do its work.  A clear chunk of ice might also concentrate solar energy in one spot, long enough to ignite some tinder.   The notion however, of starting a fire with anything less than a very good lens is nifty but frequently impractical.   Keeping the water from leaking can be difficult as is holding it still for any duration.   Even when sunlight is strong and direct an average lens will diffuse the light so much that even the driest tinder will not ignite.  This water baggie idea is more fanciful than realistic.

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A parabolic mirror or highly polished parabolic surface can also capture heat from the sun.   If held at the correct angle to the sun, the surface will concentrate the light into one small spot along the edge of the parabola.  For example a person could polish the concave bottom of a beer or soda can to a high sheen, using some steel wool.  If steel wool cannot be acquired, perhaps diataneous silica, abrasive leaves from plants in salt marshes or graphite (as in a pencil lead) might work.  Graphite is commonly used as a lubricant but it can also perform as a mild abrasive.  The polished surface (bottom of can) is then propped up by rocks and pebbles until the sun is caught at a very small spot at the bottom edge of the can.  Very small pieces of tinder are then dropped onto the hot spot and should become hot enough to ignite.

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Flashlight batteries & steel wool are a handy way to start a fire.  For many decades Boy Scout manuals have advocated this trick.  One strips a small ribbon of wool to the proper length to reach both positive and negative terminals, and then shorts it out.    Two 1.5 volt cells in series provide 3 volts, which is usually enough energy to make the steel wool glow red hot and then ignite.  Larger batteries will work also.

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Another interesting fire starting method is the ingenious “fire piston”.  This device was discovered by Europeans visiting Indonesia in the 1860’s.  (* Indonesia incorporates Sumatra, Indo China, the Philippines, Borneo and about 17,508 islands in between).   The fire piston is thought to be an ancient device because of its wide distribution.  It may have resulted from the development of the blow gun or blow tube.  The fire piston works on the same principle as the Diesel engine.  A hand sized tube is fitted with a close fitting rod (piston).  For a tight seal the rod is fitted with a gasket of string or sinew and packed with animal fat or wax.  A small piece of tinder is placed in the dimple of the plunger, the plunger inserted into the tube, and a pump or two of the piston generates enough heat (through pressure) to ignite the tinder.  The fire piston requires careful construction and close tolerances, but it is apparently a very reliable device.

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Yet another interesting proposal is that of using ammunition from a firearm to build a fire.  The notion of dumping ½ of the gunpowder from a cartridge out and stuffing in a bit of rag cloth to replace the bullet is suggested.   Ideally the propelled cloth should smolder long enough to ignite tinder (and excess gunpowder).  In practice however the cartridge primer usually just ejects the cloth and fails to ignite anything.  The process might work for someone under special conditions with the right firearm using a cartridge with the right powder.  Pistol cartridges use the fastest, most volatile nitrocellulose powders.  Shotgun powders use the equivalent of slower pistol powders.  Rifle powders use the largest grained, slowest burning powders of all; and therefore should be the hardest to ignite.  Firecracker or ‘flash’ power is faster than black powder and both deflagrate faster than nitrocellulose powders.  In any event, gunpowder from any firearm cartridge would compliment other tinder or help start a fire from an ember achieved by other means.  Gunpowder can be unpredictable or sometimes troublesome to ignite.   Many a fool has probably blackened his face or singed his eyebrows by patently holding a flame to the stuff.

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In conclusion it is hoped that the reader will part with a few new notions.   Throughout history, fire and its heat have played an extremely significant role in the development of human technology and culture.  Refined heat allows us to create sophisticated materials, it extends our lives by allowing us to survive cold weather, it generates our electrical power and kills disease in our food before we eat it.  The reader should now be better equipped to initiate a fire in an emergency, possibly using one of several different archaic methods if absolutely necessary.   If unpracticed in these primitive skills however, he or she might soon discover that what looks so simple can actually be very difficult.xlighter4

* Bit of trivia:

It may not be appropriate to call someone a good Boy Scout just because they can start a fire.  

– The Boy Scout movement began 1908 in British Isles, and spread to America by 1910.  The society attracted urbanite boys and instructors more than countrified counterparts.  For a century now, the thirteen different editions of the Boy Scout handbook have traditionally placed more emphasis on controlling fire rather than starting it.  Never has skill in fire making been a requirement for scout advancement.  In 1911 the only fire related merit badge was for Firemanship, which focused upon extinguishing fires safely and avoiding panic. Today’s equivalent merit badge for Fire Safety differs slightly by including small requirements like that of igniting a camp stove prudently. 

– Where modern Scout manuals might have more images and information concerned with outdoor skills, yesteryear’s handbooks were more moralistically toned for building leadership, character and integrity.  When examining some of the older editions it would appear that people had a more defined set of ethics than they do today.