First off, leather of any type is slightly acidic, and NEEDS to remain that way, to insure the longevity of the object tanned. The average ph of comercially tanned leather is around 4.5 or so , give or take a couple of tenths. In the words of a Leather Chemist, " a ph above 5.5, strikes fear into the hearts of a comercial leather tanner". A ph above 6 starts a destructive, irreversable process for a Taxidermy Tanner, and it only gets worse as ph rises. Past 6, the inner root sheath of a hair folicle starts to disolve. Hense, hair starts to fall out, and sometimes curls. Whats in Nair that causes hair to fall out? Calcium Hydroxide, a caustic. When a woman gets a perm, whats happening to her hair? I dont have time to explain it, but it has much to do with raising and lowering of ph.(weakening and re- stregenthing of hair) How does a high ph effect the corium, or skin itself? It causes the weakening and eventual destruction of collegen.( the glue that holds skin together)Skins that are subject to too high of a ph, will fall apart in your hands. Glen has been trying to point this out for a while. Remember the guy that was talking about loose hair after washing a cape in tide? SODIUM HYDROXIDE! Oven cleaner, sodium hydroxide. Soda ash and water-sodium hydroxide. That clump of soda ash in the bottom of a tan you are neutralizing, laying next to a skin- where did this big hole or tear come from? Neutralize carefully!
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wow. that's some damm good info oldshaver! i will add that a ph raise to 5.9 in the later 20 minutes of the tan gives me a better oil obsorption, and a softer leather. it's a tricky balance but since so many young tanners on here or having trouble getting a soft leather i feel i needed to open my yap! but i use sulphuric acid in my lengthy pickle. and some have stated on here that they think sulphuric acid tends to keep lowering as the hide ages. this could be true. and i think there may be something to this. but im still researching that matter. maybe that's the sole reason it works well for me!