INTRODUCTION to HAIR ON TANNING and FUR DRESSING

It is suggested that this section be read thoroughly to get a better understanding of the methods and principles associated with tanning “hair–on” hides / skins and to achieve the best results. FYI: A hide is from a large, thick-skinned animal, and a skin is from a small, thinned-skinned animal. A deer would fall in between. The terms overlap and are often used interchangeably.

As soon as the hide is removed from the animal, immediately remove as much meat and membrane from the flesh side. It is especially important in warm weather to get the hide cleaned, prepared, and salted as soon as possible. Using a hide scraper on a wooden beam will speed up this process. However, if it is not possible to flesh the skin right away, the hide can be frozen until it can be handled properly. (See – FREEZING OF RAW HIDES/SKINS).

Once the meat and membrane have been removed, lay out the hide with the flesh side up, making sure that there are no folds or over-lapping skin. Now you are ready for the next step, salting of the raw hide/skin. This process is also known as salt curing. Using a medium grain salt such as a feed salt or canning salt, rub into the flesh side a generous amount of salt. Be sure to spread the salt evenly.

NOTE: Always use a good quality salt. Never use rock salt. If the hide is going to be stored for any length of time, it is advisable to shake off the first layer of salt after 24 hours and re-salt with new salt.  NEVER re-use old /used salt.

It is recommended to keep salted hides up off the floor to prevent them from sitting in the drained fluids. Dried, salted hides should be stored in a cool, dry area.

If using the above procedure, and prior to salting, it is also recommended to spray the flesh side with a bactericide to help prevent possible bacteria damage and spraying the hair/fur side with an insect deterrent (see PEST DEFENSE for Taxidermy Mounts).

This is the process of bringing the dry, salted skin back to its wet, flexible state prior to pickling. It is recommended to use 4-5 oz. of salt per gallon of solution in order to prevent swelling of the hide/skin. For difficult or thick hides (i.e. African skins), the use of a wetting agent will facilitate the rehydration (HIDE RELAXER XL is recommended). To prevent loose hair, the hide/skin should be left in the rehydration solution only as long as necessary. Occasionally, the dried hide/skin will have a membrane on the surface that makes it difficult to get penetration. After the hide has become somewhat flexible, the hide’s surface can be scraped with a scraper to break the surface. It is recommended to use a bactericide to prevent bacteria growth.

Another option to the salt curing method is to soak the raw hide/skin in a saturated salt solution, eliminating the dry salting step. This is known as a salt brine solution. {As with the dry salting method, it is important to remove as much meat and membrane as possible before placing the hide in the salt solution.} There are some advantages to this method. It by-passes the rehydration step and cleans out the blood, fluids, non-tanable proteins, and dirt before the hide goes into the pickle. A good quality bactericide is recommended when using this method. To make a salt brine solution, add three pounds of salt (same type as used in salt curing) to each gallon of water. Hot water can be used to dissolve the salt, but the solution should be cooled to room temperature before placing the hide/skin in to soak.

This is an optional process by which selective enzymes are used to help remove (digest) any residual blood, non-tanable proteins, and fats which allows for more tanning sites without damaging the hair root and hair shaft. This process will provide a lighter, softer leather with more stretch. It is important to choose the correct enzyme when treating hair on hides. Using an improper enzyme can cause hair slippage. Care must be taken when bating that the soak tank is clean and that no foreign chemicals are present.

Also known as SCOURING and DE-FATTING – Hides such as bears, beaver, muskrat, pigs, raccoons, and like animals, must be degreased properly to ensure a properly tanned hide. There are several degreasing methods used. Solvents such as Perchlorethylene or Trichloroethylene 111 do an excellent job, however, they are highly toxic and require expensive equipment. Biodegradable aqueous degreasers are now available that also do an excellent job, are safe to use, and also have a cleaning effect on the hair as well as the hide. Straight aqueous degreasers (DETERGENT SR-11 is recommended) for slightly greasy skins and an aqueous/solvent degreaser (D-SOLV 60 is recommended – it has a high flash safety solvent) for exceptionally greasy skins. Another problem encountered with greasy hides is a condition known as “greased burned skins”. This is caused by the greasy raw hides/skins either stored too long or exposed to excessive heat, which causes the fats to “varnish” making it difficult to remove. For treating “greased burned skins” see HIDE RELAXER XL instructions.

The pickling of hides/skins provides four different purposes:

  1. Breaks down acid soluble non-tanable proteins
  2. Swells the corium of the hide to allow easier and a more even shaving
  3. Prevents bacteria growth when pH is held below 2.0. NOTE: It does not prevent mold and fungus growth
  4. Puts the hide/skin in a cationic state which allows penetration of cationic tans such as alum to penetrate and attach to the fibers.

There are two categories of acids: mineral and organic. Mineral acids are the strongest acids and provide a lower pH at lesser concentrations than organic acids, but are more dangerous to use and can cause acid rot in the leather when residual amounts are left in the hide.

Saving is a major key in obtaining soft, stretchy leather. The skin is made up of intertwining, continuous collagen fibers (see illustration). These fibers are tightly woven on the skin’s surface grain and must be thinned to achieve quality leather. By shaving this layer, the fibers are cut, resulting in loose ends which gives more stretch to the leather and reduces the shrinkage. Although a hide/skin can be tanned after only scraping off the meat and membrane on the flesh side (grain), the best tanning results are obtained with shaving the hides/skins.

There are several methods of shaving. One is the use of a curriers knife. This is a T-handled hand held tool with two blades. The blades have a sharpened rolled edge. The hide/skin is laid over a rounded wooden beam for shaving. A lot of experience is required to be proficient. Sharpening the blades also requires great skill. The other method is the use of a round knife, also known as a fleshing wheel or a fleshing machine. This is a power driven wheel with a rolled sharpened edge for shaving. There are two adjustable guides that control the depth of the cut. Although these machines are more expensive than a curriers knife, they are more user friendly and faster, and obtain a more even result… There are several companies that will sharpen the blades.

The term tanning is the treatment by which a hide/skin in the raw state is converted to a stable, flexible, non-putrefying material. There are many types of tanning agents available which provide different types of finished leather depending upon the application. The most common types of tanning agents are cationic mineral tans (i.e. alum, chrome, and zirconium), tannic acid (also known as vegetable tan, bark tan, or extract tan), syntans, polymers, aldehydes, and all-in-one liquid tans (see NU-TAN and TAN-X 5000).

Refers to the addition of specific chemicals that slow the penetration of mineral tans to provide a more even, leveling effect. It also gives a fuller, softer and a more stretchy leather.

The fixation of mineral tans using various chemicals such as sodium bicarbonate (also known as baking soda), sodium carbonate (also known as soda ash or washing soda), and sodium acetate.

There are several methods of oiling the tanned hide/skin, either by swabbing or by fatliquoring, which is the adding of oil to the pickle bath, tanning bath, or a separate Fatliquor bath by itself or in a combination of some or all of the afore mentioned.

There are many types of oils such as fish oil, animal oil, vegetable oil, and synthetic oil. While some are used as a raw oil, most are reacted with either acids or alkalines to make them water soluble. The penetration and softening of the oil will vary depending upon the amount of reaction. Some raw oils or neutral oils are emulsified to make them soluble in water. These types of oils are not suitable for Taxidermy Tanning, as they will wash out in the rehydration process. They also will migrate in the leather, since they do not form a chemical bond. Other oils create a waterproofing effect which is also unsuitable for Taxidermy Tanning. Swabbing oils are the best and most economical choice for Taxidermy Tanning. They give a fuller, finished leather with more stretch and less shrinkage. (SWAB OIL LT, SWAB OIL MD, SWAB OIL HV, or SWAB OIL SOL are recommended. Each oil has a specific use – please see catalog for descriptions). It is advisable to use a small amount of Fatliquor prior to swabbing. This will help