I am about to attempt to tan my first hide. I am using SA-200 saftee-acid for pickling. Do I need to salt dry the hide before placing in the pickle. If so, Why?
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I have been using formic acid pickle for years, and never pre-salt, unless the cape is beginning to sour. If you have green spots on the cape, or if it smells bad, salt and let dry. Hopefully, this will set the hair.
Salting removes the water from the cell structure and creates a void that when the skin in entered into the pickle, it will more readily absorb the acid and fix the cell structure. Skipping that step during the tanning process sets an unstable situation to work. The acid will have to dilute into the water that's already present and you risk the additional step of total absorption within the skin. If you're not going to salt, you might as well dry preserve the hide.
Then you are not tanning. Like George said,salting removes the moisture, or most of it, from the tissue interstices and the cells too. Water remaining in the cellular matter will certainly inhibit the presupposition that the pickle does by breaking down the tissue and preparing it for a tanning process. If there was a better way, millions of cowhides wouldn't be salt dried before tanning. You can substitute potassium chloride for salt, as some commercial tanneries do during the drying process, but to eliminate it is tantamount to leaving the scotch out of a Rob Roy. If the salting step could be eliminated in the leather industry, shoes would be cheaper...maybe. I figure if the real pros do it, who am I to re-invent a 2000 year old wheel?
You both mention the difficulties caused by "water" in the skin; are you saying you put the salt dried skin directly in the pickle? Don't you rehydrate the skins in water and wetting agent before pickling? And doesn't that saturate the skin with much more water than it had when fresh?
To answer Steve's question, yes he should salt, because the manufacturer of the product that he is using recommends it. However, he should also re-hydrate the skin before pickling, and all that extra water really does slow down the pickle penetration. The properly salt cured hide (12% to 20% salt content) will hold the hair however until the pickle slllllooooowwwwlly penetrates in a static vat.
Then he should basify in baking soda or soda ash solution.
The result? A raw skin. More open and cleaner, but still raw. Most manuals and texts recommend skins should be "as close to raw as possible" just before tanning.
Why do all that then? Most tans penetrate slowly and the skin can begin to rot before the tan can do it's job. However, many tanneries prefer using fresh skins, and are able to do so by using cold storage and transportation of the skins to the tannery, and then using mechanical manipulation of the skins to promote penetration the chemicals in whatever process (bate, lime, de-lime, tan etc.) without ever salting or curing.
To say that any skin that hasn't been salted is not tanned is not true. I would gladly discuss this at length if anyone is interested. It's about as exciting as watching paint dry, but I suppose painters might even find that process intriguing.
Now what are you saying? I DON'T need to salt? Since this has gotten technical, maybe you and Bruce Rittel need to compare notes. I see thousands of deer hides going to tanneries and they certainly are salted hard and IF memory serves me correctly, many old time taxidermists never bothered to get past the pickle stage at all. But then again, I've gotten smarter in my old age and don't bother with any of it anymore. I send them out to other people who know what they're doing.
The tanning process may vary from place to place and many steps like fatliquoring and other specifics may be added or deleted to create one variation or another, but it would be a foolish shipper who would want to bear the expense of shipping wet hides halfway around the world.
Most leather goods start out as dry salted hides. The hides are dried to prevent bacterial action prior to tanning processes. Relaxing a hide does more than just wet it, it removes the salt content and prepares the hide for liming or pickling. Pickling, as I understand has one purpose and that is to lower the ph of the hide. And prepare it for the tanning salts.
To say that a hide doesn't need to be salted prior to tanning may be correct in a perfect world, or one built from unlimited freezer space, but that ain't so. Salt draws more than just water from the hides, it breaks down some of the fascia and other components and prepares the hide for use.
When dehairing takes place, it is the deliming and the bate and the pickle that returns the cellular matter to a tannable state. The mechanical manipulation and splitting equipment and all the other accoutrements of a major tannery are some high dollar toys and completely out of reach of any taxidermist I have had the pleasure of meeting. You could go on to tell them that the soda bat you mention has been replaced with CO2 and water to instead. Or that today, fatliquoring materials are synthetic.
Tanning has gotten pretty high tech over the years, but for your basic hole-in-the-wall taxidermist, I recommend salting that hide before doing anything else. Hell, you might have to take time off to go fishing or something. It is a good practice. It is necessary to some tanning processes, and not to others. I asked a fellow on the British leather industry forum what process was most common in the British Leather industry. He told me that there were ten basic steps between the carcass and the finished leather in what they call the wet blue state. The first item he mentioned was salting. If it is good enough for the Queen's saddle, it is good enough for me.
As I said before, I never salt before pickling. I did at one time,but tried it without salt, and there was absolutely no difference in the finished product.So, for several years now, I don't salt before the pickle.Saves a lot of salt and time. My capes are tanned through and through,have all the stretch I can use,and does not shrink after I mount. They are easy to shave, and turn out real thin. I think "if its not salted, its not tanned" is not really correct.I will say that I use this method on capes only. All other skins are salted and dried.
make some good points. George, Bruce and I are good friends and have compared notes often, and I'm not saying you should do anything. My main point is that salting is not a REQUIRED step for tanning. However, I completely agree with you that any skin going to a tannery should be salted and dried hard. Bulk processing exigencies don't leave much room for babysitting potentially problematic capes, and a wet, unprocessed cape is a potential problem. This isn't a knock on tanneries, I used them exclusively for 9 years and loved the results.
A good example of tanned skins not being salted is all the trapper skins that are tanned every year that have been air dried. Also, my office is littered with flat wt skins that are perfectly tanned that were never salted OR dried.
Fresh hide processing is very common in Europe (where the concern is salt pollution) and anywhere else where the abattoir and tannery are proximate and the weather isn't too hot most of the time. Practical experience and scientific record keeping have shown that properly packed hides in shaved ice layers can be delivered up to about 500 miles. Refrigerated trucks extend that limit. But Cur, salting doesn't bring the tannery any closer. The hides still have to be shipped, and a hundred-hide block of cowhides cured with 40 to 100 pounds of salt each is just as heavy and costly as fresh hides in ice. Of course the difference, as you point out, is that salted hides don't spoil if the truck has a flat, and therein lies the whole reason for salting.
As taxidermists, we often have opportunity to immediately begin the tanning process, if we don't have a lot of other pressing responsibilities. "Immediately" is the bugaboo. Bacterial infestation proceeds at a rate of about 10 fold increase every 8 hours. 16 hours above 65 degrees is enough to cause some hair loosening. So if you're not ready to proceed with your process, freezing or salting should be done without delay.
By the way, I do know of one mechanical-manipulating, medium-dollar, fairly-low-tech toy/tool/answertoalltanningproblems that is within reach of nearly all taxidermists! But that wasn't the discussion!
...Salt before tan is to prevent hair slip otherwise you could go to tan right away I would Imagine..Lloyd
salting does help in the shipping and storage of hides prior to tanning? It would seem to me that if one was to be able to pickle and tan a cape with out the need to ship it away then the salting step "could" be left out. Folks...look at the garment tanning industry. These "trapper style" skins are UNSALTED! It would seem to me that if these could be used to make garments and not salted, then use in our trade would also fair well. Just my observation....
I would like to start keeping our hides from our cattle business, in hopes to learn how to tan the hides. I have NO CLUE what I am doing. Could someone with some experience give me some sound advice? We have mostly feeder cattle which weigh 500-700lbs if that matters any. Thanks much Stacy
If your hide is fresh you can put it strait in a 18 degree salometer pickle with a PH of 1 to 2.5 with most acids formic, sulferic, citric, etc.. You should have no problems with slip using this method. But salting the hide and letting it set for at least 48 hours is advised and a cheap bit of insurance to set the hair. Adding a little alum to the pickle can also help hold the hair. GOOD LUCK AT TANNING!