OK, I am at my wits end and it is time to seek assistance. I have been doing my own tanning for a couple of years now with an auto tanner. I know how some of you feel about those, so this post is only directed at those of us who use them and enjoy tanning our own stuff.
A few months ago I had a man call and ask if I used alum to tan my hides. I told him that indeed I do. He in turn told me that his father passed away and had owned a chinchilla ranch not far from my shop. He used alum to preserve the pelts and now that he was gone this man wanted to give me the remaining alum. I was informed that he had 350lbs of unopened alum that he would like to give away. I couldn't get into my truck fast enough!
Upon arrival I found that the 350lb barrel of alum was not the kind I usually use. I use Aluminum Sulfate. This stuff was marked Ammonium Alum on the barrel. I took it anyways. Well, Tuesday I ran out of aluminum sulfate so I decided to give the ammonium a try. I chose 2 mulie butts to experiment with. I put the same amount of the ammonium that I would have used had it been Aluminum s. I mixed up a normal batch and let it run overnight. Yesterday I took them out and fleshed them. Then I put them back in and let it run a while longer. I took them out and I did everything identical to how I usually do it. This morning I looked at one of the butts. I noticed the hair was looking kind of ragged so I used my fingers to smooth it out. Huge clumps of hair fell out and it was not just in one spot, but all over the hide. I tossed it in the trash and began trying to figure out where I may have gone wrong. My first guess is that the Ammonium is a poor substitute for aluminum s. Has anyone ever used this stuff? I'm glad I did my little experiment, but I would like some input. Hey, John C, tell me what happened!
Thank you for any help!
-Jeanette
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Should have been okay. Did you add the salt to prevent the acid swell? You should also add a buffer at some time in the process but the lack thereof would not have caused slippage.
Check the bag again for the word "hydrated". Hydrated alum does not work at all and the hair will jump out.
We recommend that you shave the skin after being in the mix for no more than 2 hours. That gets the surface opened up and the skin thinned a bit. However, the profound slippage you're describing would not have happened just from being left in too long.
Somehow the mix is not right.
That's the tech name for Ammonium Alum - Ammonium Alum is what is called it's Trade Name. It can be used the same as plain old Aluminum Sulphate - same dosage - same formula - except it tends to shrink the skins a lot more than plain Alum. That's why Fur Dressers prefer to use it over plain Alum (Aluminum Sulphate). Of the 3 types of Alum Ammonium Alum has the most shrinkage - Potassium Alum has less - and Aluminum Suplhate (plain Alum) has some, but the least of the 3. Otherwise, as I said - Fur Dressers love it!
One point that was brought up - did you use Salt with it? You must -otherwise it will definitely give you problems.
for answering my post. I had hoped that it was my faut. I was afraid that the ammonium was going to be useless for tanning and that I would end up tossing 350lbs of material. Indeed the fault was mine. I did not salt it prior to tanning. I let it run overnight in the tanning machine prior to fleshing. When I did start fleshing i noticed a strong rotten smell. I was not alarmed by this since most capes get folded up in the tanning machine. However, when i pulled it out the next day the smell remained. I hung it up and let it drip dry last night. Now I know that the ammonium is OK to use and what to do prior to tanning. I had never salted hides when I was using aluminum sulphate and the capes always came out feeling like butter and had stretch for days. Thank you both for your advice and I will put it to use tomorrow morning.
Thank you! -Jeanette
No need to salt before tanning! The salt you need is in the tanning solution mix. Per gallon of hot water (105 to 112 degrees) add 6 to 8 ounces ammonium alum and 8 ounces salt. Then after the skin has been in the machine a couple hours and shaved, add a tablespoon baking soda at a time until you've basified to 3.9 pH. Run the skin in that a couple hours and you're done!
This salt prevents acid swelling during the tanning process. The variance in the ammonium alum is because of the possible differences in the amount of impurities in your water.
The more impurities, the more you'll need. You can tell by the amount of stretch you're getting. The ammonium alum is used as a coagulant in water purification. This means that if your water has a lot of impurities, the alum will bind to them and effectively be removed from solution. Conversely, the more pure your water is, the more of the chemical will go into the skin.
So if the skins are coming out stiff with no stretch, just cut back on the chemical a couple ounces and that should fix the problem.
I have to add, none of this would have anything to do with a strong rotten smell. That just about had to occur before the tanning started.
A proper tanning bath would definitely have killed the smell and saved the skin, but even in an errant bath I don't think the rot could have developed that fast.
Steve,
I did a redo on a mulie butt. I took a hide that was free from any rotten smell and I knew it was in good shape. I mixed up my normal batch -including salt, saftee acid, and Downey fabric softener. I let it run for 2 hours and fleshed it. No smell, no slippage. Stuck it back in my auto tanner and ran it overnight. It tanned well and there was no slippage. It is not as stretchy as the aluminum sulphate tan, but appears to be holding the hair tight. I think my problem was the hide that I used on my first attempt was on the verge of going bad. I still like the Aluminum sulphate better. Can I mix half and half alum sulphate and ammonium? Thank you VERY much for your responses!
-Jeanette