The easiest way to tell you is to soak it in alkaline water and dry it. I have soaked it myself before: it has a great influence on the quality of the product. The operation method must be strictly implemented. The purpose of soaking is to restore the fresh epidermis of rawhide, remove some protein, and remove impurities such as blood stains and feces. The soaking temperature depends on the kind of hides, and is generally 15- 18C. For example, the skin below 18C softens slowly, and bacteria above 20C are easy to multiply. Soaking time: Generally, salt skin or dried salt skin can be soaked in running water for 5-6 hours. If the dried skin or salt dried skin is stored for a long time, it should be softened by physical or chemical methods during soaking. The soaking time can be 20-24 hours. It is required that the skin flap should not be wet, soaked, soaked and even. Pay special attention to the temperature and soaking time when soaking. Based on the principle of rawhide swelling in alkaline water, the soaking time of rawhide can be reduced and bacterial reproduction can be inhibited. Sodium sulfide, sodium hydroxide, ammonium hydroxide, sodium sulfite, etc. Often added to the soaking solution. The dosage of sodium hydroxide is 0.2-0.5g/L, and the dosage of sodium sulfide is 0.5-1g/L. ..

(2) Internal shearing: soak in water to soften the fur. Spread it upside down on a semi-circular log and scrape off fat, leftover meat, etc. Attach to the meat surface with an arcuate knife. In order not to hurt the hair roots, you can spread a thick cloth on the log first when scraping. Crushing is closely related to the subsequent degreasing. If there is too much residual fat, it is not conducive to degreasing. The function of scraping the inside of the bow knife is to make the residual fat in the skin rise to the surface of the skin by extrusion, which is beneficial to degreasing.

(3) degreasing and washing: the quality of finished fur depends on whether degreasing is complete or not. In the degreasing process, the fat should be removed without damaging the fur. Saponification method is mild, and its principle is to use the properties of soap generated by alkali and grease to remove grease from the coating. If the alkali solution is too concentrated or strong alkali is used, the cutin of fur can be destroyed, and the hair will lose its luster and become brittle. Generally, soda ash is used, which is weak in alkalinity, and can remove grease without causing damage to wool. But the concentration of lye should be controlled. If the concentration is too low, the purpose of degreasing will not be achieved. The product hardens and has the original smell of animals, which will also affect the next tanning process and make the skin stiff and not durable. Degreasing method: firstly, prepare degreasing solution, 3 parts of soap, 0 part of sodium carbonate/kloc-0 and 0 part of water/kloc-0. Slice the soap first, boil it in water and dissolve it, then add sodium carbonate. Add warm water (38-40C) which is 4-5 times the weight of wet skin into the container, add 5- 10% degreasing solution (rabbit skin and sheepskin 5%, dog skin 10%), then put the shaved fur, fully stir it, and change it again after 5- 10 minutes. Degreasing liquid can also be prepared with washing powder (3g/L) and soda ash (0.5g/L), so that the weight of the treated liquid and wet skin is 10- 12 times, heated to 38C, degreased and stirred for 40 minutes, and the enzyme-added washing powder on the market is better, 3g washing powder is used with 1 liter of water and soda ash is 0.5%. Furs degreased within the specified time should be washed immediately, soap solution removed, and then washed and rinsed. Peel and dry.

2. Tanning process (only alum tanning method, its source is simple and convenient). Prepare tanning liquor, 4-5 parts of alum, 3-5 parts of salt and 0/00 part of water/kloc. First, alum is dissolved in warm water, and then the remaining water and salt are added to make them mix evenly. Principle: After alum is dissolved in water, it generates free sulfuric acid, which can make protein fiber in skin absorb water and expand. The purpose of adding salt is to inhibit expansion, but the amount of salt added depends on temperature. You can add less salt when the temperature is low, and more salt when the temperature is high. Generally, 0.7-2 parts of salt can be added according to 1 part of alum. Tanning method: the ratio of material to liquid is 4-5: 1 (when the weight of wet skin is 1, the tanning liquid is 4-5). Put it into a container, so that the fur is fully soaked in the feed liquid. In order to make the feed liquid evenly penetrate into the cortex, it should be fully stirred (preferably with a roller), stirred once a day after overnight for about 30 minutes each time, and soaked for 7- 10 days to finish tanning. Inspection method: If it is tanned, take out the soaked skin, with the skin board facing outward and the plush folded inward, and press the corner hard to remove all the water. If the folded part is white and unclear, it looks like tissue paper, which proves that tanning is over. The low water temperature during tanning not only prolongs the tanning time, but also hardens the cortex. It is best to keep the temperature at about 30℃. After tanning, don't wash the inner surface with water, just wash the rough surface with water. Alum tanned fur is white and soft, but it lacks water resistance and heat resistance.

3. Finishing process: (1) Fatliquoring: The original fat in the skin has been removed during the processing. In order to form a protective layer of fat film around skin fibers and improve the softness, elasticity and strength of skin, fatliquoring is needed. Now a simple fatliquoring formula is given for reference: castor oil 10, soap 10 and water 65438. Combination of inner surface and inner surface >: Let it dry overnight. (2) Moisturizing: After fatliquoring and drying, the leather board is very hard. In order to scrape it soft, you need to spray water into it. This process is called "moisturizing". Fur tanned with alum can be brushed with a brush or sprayed with a sprayer. Because of its lack of water resistance, it is best to coat it with alum tanning solution, and then coat the coated fur on the inside and inside. Let it absorb water evenly and then scrape it soft. (3) Softening: Spread the fur after moisture regain on a semi-circular wooden board, with the fur face down, and gently scrape the inner face with a blunt knife, so as to lengthen the leather fiber, expand the area and soften the leather board. (4) Hair shaping and trimming: In order to make the scraped leather board smooth, it is necessary to shape it, nail the hair face down on the board and dry it in the shade. Then take it off the nail board and trim it. Then comb your hair with a comb. If the skin is broken, it should be stitched up. It's all done. Attention should be paid to this method of curing leather. (1) This is a fur curing method, and leather has little influence, for example; Suede, in the process of treatment, will shed its hair and become hairless. After nitrification, the effect is not significant. It can't be used as a scabbard because it contains salt. This is a rusty knife. However, leather nitrates well because it contains less oil. (2) If you are making decorative leather, you must peel it after the opening, that is, cut a knife from the midline of the hind foot and peel it into a tube skin as a whole, which will look good.