Dehairing hide using lime

Submitted by Ruth Maxey on 10/31/2002. ( ) 63.168.158.208

I have tanned several hides using the alum and salt method. This year I would like to tan one without the hair. I know lime works, but need to know how much lime and also need to know if there are any additional steps between soaking in lime water and putting hides in brine.

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Lime

This response submitted by Leather Neck on 10/31/2002. ( ) 152.163.188.199

An easy way to use lime for unhairing is to simply fill a vat with water and add the lime in excess of saturation. The water in fact can only dissovle a rather small amount of lime and the rest will fall out of solution and settle onto the bottom of the vat. This is no problem. Every day just be sure to remove the hides and stir up the lime liquor well, then put the skins back. Depending on the hides this will take a few days i would think. You can check the liming by rubbing a portion of the hair-hide and observing how easily the dissolving hair rubs off. After several days it all should be gone. Lime is safe and works good, but may take a little patience and practice. Tanners today in addition to lime give "sharpening agents" to the liming bath in order to speed up the process. Chemicals such as Sodium Sulfide and Caustic Soda are common in commercial application. After liming it is important to rinse the skins good and delime the hides. I think in this forum there are many types of deliming acids (agents) available and others here can expand upon this point. I do know that Weak Organic acids such Acetic (vinegar) work very nice. Ammonium Chloride also very good for deliming.


Sweating

This response submitted by Leather Neck on 10/31/2002. ( ) 68.155.32.98

If you want to experiment with another method of unhairing here is an interesting method. This technique uses no chemicals and dates back hundreds... if not thousands of years.
Before the introduction and discovery of "liming agents", ancient tanners observed that if raw hides were kept in a warm and humid environment, within a few days the hair would begin to slip. Keeping the hides a little longer like this greatly loosened the hair to the point that it would be possible to "scrape off" the hair with a blunt knife on a beam. The effect due to bacterial attack of the hair root. Not a choice method and could you imagine the stench? If the sweating process got out of hand could also damage the hides without a doubt if bacterial degradation accelerated.


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