Preserving Animal Skin
Learn the art of preserving animal skin. To produce leather,fur industries use animal skins and hides.This results in a tough,durable material that can be used in the clothing business.
The raw by-products in the meat-packing industry like calf, sheepskin and cattle hides are first cured by soaking them into salt solutions. There are two ways of doing it. The first one is called wet salting. It is done by alternately piling up the raw animal skins on top of one another while salt is being sprinkled into each of them. They are left that way for 30 days so the salt could really get through the skin. Another qiucker method is called brine-curing. The skins are first placed inside large tubes called raceways. There, a disinfectant and brine slowly penetrates into the skin.After 16 hours, the skins are ready for the next process.
In the second process, the skins are first soaked in the water to replace the moisture it lost during the curing process. This takes for about 2 hours to as long as 7 days. After that, a machine removes the inner part of the skin surface. To easily remove hair particles from it, the skins are soaked again in a solution with a mixture of water, lime and sodium sulfide. They are then passed through machines to dehair them. Another method known as sudding is used to make sure there are no hair particles left from the skin. It is done by scraping the unuseful particles with a knife using the hands.
The next step is by soaking the skins again into a weak acid solution to recover from the swelling it had from liming it. A material exerting a lesser concentration of force which contains chemical substances try to soothe these skins to enhance its texture and improve its quality.
The fourth step is called tanning. This has 2 forms: vegetable tanning and chrome tanning. In vegetable tanning, the tanning substance is known as tannin. The skins are contained inside moving frames and transferred into tubes which contain stronger tannin called liquors. Week after week, more tannin is added to the tube until the skins have absorbed enough of it. Another method called chrome tanning is where salt and acid is mixed into the hides. They are then placed in a large drum which rotates the skin while they are soaked in chromium-sulfate solutions.
Once tanning was done, the leather is then dyed on the desired color.Oil and greases are used to dip the leather into. This results in a wide range in the color of leather. They are then placed on frames and dried on temperature-controlled places.
The leather is then finished by spreading dyes,waxes and pigments to give the leather a brilliant and natural look. Varnish is then polished into it to give the leather its sparkling shine. Some heavier leather materials are then brushed with finishing substances. To give it its smooth texture, leather is then rubbed with sandpaper. This produces a product known as suede.