Aluminum Sulphate as a tanning agent

Submitted by Steve Rotramel on 1/21/1999. ( )

This forum is Great! I've been reading all the questions and comments and found it very instructive. At the risk of sounding self serving, I'd like to put in my 2 cents worth on this subject.

A few facts:

Aluminum sulphate is the main tanning agent of choice, used in this industry by most of the big tanneries and has been for years. That's because it works. It absolutely sets the hair. It yields an excellent skin, with very good stretch and low shrinkage. When you're tanning someone's Bongo that they spent $40,000 getting, you can't take chances.

It's the cheapest tan to use by far. I routinely give out the formula for our tan, and if you buy your own chemicals, you can tan a deer cape for about 25 cents.

The tan does bind to the fibers and it does permanently stabilize the skin. The shrink test proves that. The shrink temperature is lower than some other tans, which is said to be not as good. I agree that it could be critical if you intend to boil your skins, but in a practical sense, the point is moot.

It is the easiest tan to use by far. You can check the ph; I never do. You can wear gloves; I never do. You can put it down the drain or in your driveway. You can drink it with no ill effect except to your taste buds. In our system, once a skin has been shaved, it can sit in the tan for an hour, a day, a week. Very worry free.

It is also one of the most effective tans in stabilizing the skin. The skin can be stinking, dirty, slipping, and ready for the trash can, and this tan will save it in most cases. I have tanned a number of skins that I know for certain would not have survived any other process.

My intention here is not to put down any other system. There are many that are very good. Bruce Rittel has helped me immeasurably in this whole process and he has some great products. They work also.
The point is that for me and many others aluminum sulphate can't be beat for ease of use, cost, quality, effectiveness, longevity and peace of mind.

Disclaimer: Any sarcasm noted in the above is absolutely good-natured and I hope it's received that way.

Final note: I thank God for the success of our products from start to finish. I also thank all those who have helped us along the way. This industry is not perfect and there are bad apples, but overall it's the people, many represented on this forum, and their willingness to help their fellows, that makes this a great business to be in.

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This response submitted by Dave B. on 1/21/1999. ( )

Hi Steve

I love this site to, I just bought a computer and since
I found this site I have learned quite a lot.

I use my own formula in the tanner to save money,
I quick flesh raw cape, put in 2 gal h2o 8 oz of
aluminum sulphate, 8 oz salt and about a tablespoon
of sodium carbonate, 1/4 cup of oil (I cut back on oil)
tumble for 1 1/2 hour flesh and in for 1 1/2 hour.
I have stretch and tight hair. Thinking about not
putting any oil in tanner and just brushing on after.
what do you think, and is my pickle mixture ok.
see ya!

Sorry, but I'm not going to drink it!

This response submitted by Keith Daniels on 1/22/1999. ( )

Steve, I think you did a little diservice to some readers. Aluminum Sulphate and water create Sulphuric acid, (battery acid). This is not only very corrosive, it's also poisonous, I really don't think making the statement you can drink it is a good idea. Yes I do use it some in the tannery, but there are better choices on the market. Why is the boil test important? even though you're not going to boil your mount? How about it shows the fact that the skin is not as completely tanned, the less tanned the quicker it will curl. And yes Aluminum Sulphate will give you more shrinkage, less stretch and a less stable tan. It's big advantage is it will swell a skin real nice for shaving and it's cheap!


I Think It Is A Matter Of Abilities...

This response submitted by John Bellucci on 1/22/1999. ( )

Hey Guys,

As someone who has tanned using both Aluminum Sulphate and Lutan-F, as well as mounted mammals tanned by both methods, I've come to the conclusion that success in the final result - the mount - has plenty to do with one's skill-level or abilities.

This is not a statement against anyone, whether just starting out or a seasoned pro.

What I mean is there is a certain amount of knowledge gained with each mount one does. It really shouldn't matter what tan was used to prepare the hide for mounting - so long as it is a good tan. If one knows the things needed to get that animal together, then one will in fact get that animal together.

I will admit this right here - right now. My big Barbary Lion mount that I am so proud of, as the culmination of all my research and gained knowledge, was beautifully tanned By New Method Tannery in San Francisco back in 1985, and we purchased him in 1986.

It's no secret that they tan with the old reliable Aluminum Sulphate tanning system, and that's just how this big `ol boy was tanned. I do think this tanning method is best for those "tender" African skins, as the hair does tend to be set by this more astringent product.

As usual, these projects we do for ourselves are put off seemingly forever, so this big `ol lion was stored "dry" in one of my chest freezers - cold storage - until 1995!

I'm here to tell you, that lion skin stretched out just as beautifully as any Lutan-F tanned skin - and maybe even better - if I may dare say.

It not only stretched out, but stayed that way. There was no pulling back of the skin to it's former dimensions and there is no drumming anywhere on this mount.

These results, I believe, are not only due to a successful tanning method, but are also attributable to the fact that my skill-level has allowed me the ability to succeed, no matter what the tannage used - AS LONG AS IT IS A GOOD TAN!

These abilities are developed over years of practical experience and a willingness to continue to learn. This is an important point I always try to relate to newcomers to our industry. Your skills will come with time, and perserverence is your best friend.

I have had equal success with Lutan-F tanned large lifesize skins of deer, bear, cougar, and so on. To date, I have not had a problem mounting a skin tanned by either method. I do prefer my African skins tanned with aluminum sulphate only because of the long history of success this has had for African skins.

I also prefer it for skins that are "ify". I especially like to mix it 50/50 with salt when I'm salting a slightly "greeny" or stinky cape or skin. The aluminum sulphate "sets" that ify hair in no time flat!

Those skins I suggest to the tannery need the aluminum sulphate tan. A tannery that will accomodate such requests is tops in my book. I do still like Lutan-F tanned deer capes, and other lifesize skins. Like I said, one's skill-level will determine one's ability to adapt and succeed, using either of these tans, or others that have been written about in these forums.

Keep the good discussions going, and good luck to all... John B. (Hooray - he's finished!!!)

Okay, Stop drinking the Tan!

This response submitted by Steve Rotramel on 1/22/1999. ( )

Okay Keith, your point is well taken. So everybody who is drinking their tan - STOP! My point is that the tan is not poisonous. Even common table salt will kill you quick if you eat too much at once.

The boil test shows at what temperature the tan releases from the fibers, no matter how much is present. It does not test the completeness of the tan, unless you are comparing apples to apples. For example, a skin that is completely tanned with aluminum sulphate may still shrink at a lower temp than a partial tan with another product and vice versa. The value of the test is in comparing different tanning methods rather than in comparing different tanning products.

And the rest is a matter of opinion, and I thank you for sharing yours!

Dave's Tan Formula

This response submitted by Steve Rotramel on 1/22/1999. ( )

Dave - That is about half the tan concentration that we recommend. Are you also use a bacteriacide or maybe Bascal S? That might be a good idea to prevent any spotty slippage with your formula. Most capes would be fine but that occasional one that didn't lead a charmed life might cut loose a little on you. As far as oiling, you can pretty much follow your own heart on that. I like to use at least some in the tan because there is an additive to promote absorption. Good luck and good business!

One more word...

This response submitted by Steve Rotramel on 1/22/1999. ( )

I want to stress again, my defense of alum as a tan is not intended to denigrate other tans! I'm glad that others work! I'm especially glad that they work in our machine! I have no vested interest in promoting alum. Yes we sell it, but again I am happy to give out the formula to anyone who wants to mix their own. My sincere opinion is that, all things considered, it is safe and very effective.

Take care all. I just got my phone bill and I may be signing off for a while. I got the no-server-in-our-town blues!

Talk to me at Indy

This response submitted by Keith Daniels on 1/22/1999. ( )

You're going to be there, so will I. You can explain how pressure makes the tan work quicker there, I'm interested to hear and it won't cost a phone bill. Also please explain the not poison part. Keith

Not Poison part: Aluminum Sulphate

This response submitted by Steve Rotramel on 1/25/1999. ( )

Keith, your query got me to thinking I should get some clarification on this question myself, so I called General Chemical in Syracuse and talked to one of their chemists (Steve Faigen, 1-800-255-7589) and asked him about this. He told me the same thing the last chemist I consulted about this which is:

1. Food grade Aluminum sulphate is not poisonous. It is used for making pickles, water treatment, etc. You can find this in your grocrey store labeled "Alum".

2. The difference between food grade aluminum sulphate and what I sell is the amount of trace minerals allowed in production. The difference is extremely minute. I asked him plainly "Is this poisonous?" his answer "No".

I actually went to a show one time to do a demonstration and found that I had forgotten to bring any of my tanning crystals. I went to a local grocery store and bought all the alum they had and used that. It worked beautifully.

Now about the pressure - Why does it speed processes? The short answer is I don't know for sure. I guess the way I compare is if you took a sponge saturated with fresh water and dropped it into a bucket of salt water, the water in the sponge would eventually become salty. If you instead squeezed the fresh water saturated sponge in the salt water, it would immediately be full of salt water. Incidentally, the fresh water would somewhat dilute the salt water until it reached parity. That's why we use a higher concentration tan than most.

To briefly answer another question I have seen asked, the pressure on the skin under water is the same as shown on the gauge. Fluids by nature are not compressible, so they transfer pressure directly, hence the use of hydraulics in many other applications.

Point Well Made

This response submitted by Keith Daniels on 1/25/1999. ( )

Okay, first of all let me say, I never attacked Aluminum Sulphate. I did say there are better choices, and will stick to my guns on that, need more proof, look at all the taxidermy tanners who have left Aluminum Sulphate for Aluminum Chloride. ( Lutan) Okay, it's not poison. The grade I use, Dry Alum, has an MSDS sheet that will definately make you sit up and take notice, and yes so does Lutan. What does this mean? You need to be careful with all of these chemicals, and your crack about it being safe to drink is way off base. Yes I realise only an idiot would do so, but that doesn't change the fact you need to show a little responsibility in your promotion.

My MSDS says things like this. Inhalation-may irritate respiratory tract. Ingestion-may cause nausea, vomiting, or purging. Human FATAL dose recorded at 30 grams.

Normal handling- avoid contact with skin, eyes, clothing. Avoid breathing dust or mist.

And I could go on.

Okay, it's not poison, but I think just this little bit should prove the point that you need to take the handling of all these chemicals very seriously, and making a joke out of someone raising a legitimate concern is getting a little on the tacky side.

As for the rest of the questions raised a while back by the other man, yes I still want to hear the answers to those too. I do know a little about skins, and think that salting as a first choice, and air drying as a second, are pretty important in the process, even Bruce has made reference to this step and its importance in numerous post here, and magazine articles. ( yea I know, I actually sit down and read something other than this thing at times)

I feel these are legitimate questions in your process, and would be interested in what the answers are.

Now, the only problem I have with your machine, well actually two problems, is you don't make one big enough for me here, and even if you did I probably couldn't afford it anyhow. Oh well, gonna get rich some day, just gotta figure out who he is. Keith

Steve & Keith

This response submitted by Roger on 1/27/1999. ( )

Steve & Keith- I enjoyed your discusion on tanning. I am interested in learning tanning being a hunter/trapper. I dont know which method is best but as a chem tech at a power plant I do know what Steve's chemist said was right. In a nutshell it forms a real mild based acid(sulfuric) and aluminum hydroxide which the acid overides. it would have a pH around 5.5-6.0 with 7.0 being nuetral. No I wouldnt drink it either but wouldnt hurt you and also battery acid is hydrchloric acid which as far as acids go is a mild acid to, with a pH of 4.0 to 5.0 Full strenght sulfuric is real nasty at about 2.0-3.0 I have been burned by both. Also to anyone reading this ALWAYS pay attention to MSDS sheets! The people that wrote them put the warnings on them for a reason. Thought both of you might be interested in this. I wish I had either one of yours knowledge about tanning though. Take care both of you roger

Hi Roger

This response submitted by Keith on 1/27/1999. ( )

Is there more than one kind of Aluminum Sulphate? When I mix mine up it will give me a P H of 3 real easy, so common sense tells me that if you just wet it into a slurry it's going to burn you pretty bad. Yes I always pay attenyion to MSDS sheets, that's why when it tells me what dose is fatal, I simply can't believe this stuff can be drank with no ill effects, not to mention, and correct me if I'm wrong, swollowing the Aluminum itself. Sure it might not be much, but there wasn't much lead in the old paint, you know the stuff kids would eat chips of, or in a relaoding or smelting room, but people have had problems with lead poisoning from years of exposure to these situations. Keith


This response submitted by Roger on 1/28/1999. ( )

Keith-Yes and no to your first question yes there is diff grades and % of Alum Sul. Alum as Steve said is used for several canning things so its not poison. i for one have put a touch of alum to lips and puckered up like a 16 year old on his first date. I should have made myself clear I wouldnt drink it I was talking about it hurting your skin. I kind of take it that was basicaly Steves point that is is fairly safe which that is what it is fairly safe. I work with some nasty stuff so have been burnt,overcame by fumes and also had reactions cause fires.(one by not clearly looking at a msds which would have saved me)Chlorine Powder residue in a bucket that i didnt wash out and biocide makes a heck of a fire. Now as far as the pH I could be off a little and I will ask are Senior plant chemist, but more than likely you are using test strips that are not toataly accurate and also so many things affect true pH. You can take pure Demin water for instance and by blowing on the water make it acidic or basic(caustic). Take care Roger

My Experience

This response submitted by Keith on 1/28/1999. ( )

Roger, I haven't used strips for years, we use electronic meters, and have to replace probes every 6 to 9 months. It really doesn't take much Aluminum Sulphate to get the PH down to 3.0, about 2.5 oz. per gallon, which is roughly what a tan will come out to when you use water volume/weight formula, will get it just about here, and my city water starts at about 8.4 PH. One time, just for the nuts of it, I put the probe in a bucket of Lutan that was premixed before adding to the tan. Now this is a strong solution, 10 to 15 lbs. in 3 gallons of water, and I can't tell you what the PH was, because when I put the probe in the needle dropped so hard, and so fast it literally bounced on the peg, so I quickly pulled it out of the solution. Now this is enough to tell me to take this stuff very seriously. I did have an employee (not for long) who didn't listen to me and stuck his bare hand in one of these mixes once. In just a few seconds his hand and arm was noticably red, and he complained about a burning and itching for a good part of the day.

The sulphuric acid I have played with has had a much more violent reactiion than the formic that we use in the shop everyday, and I have got stupid and poured foric with no gloves or respirator, you know - it's just a little bit don't need to get dressed up, and not only inhaled fumes, boy, talk about a pounding headache, but also gotten splashed on the hands. When this happens you need to get to the sink in a hurry, then if it happened to be on a finger nail, it would throb for a long time, much as if you hit your finger with a hammer.

Needless to say, I'm still quite confused and really interested to learn more, but for now, since my MSDS does say this stuff can be fatal, I will treat it with one heck of a lot of respect.



This response submitted by Roger on 1/30/1999. ( )

Keith-Boy when your talking 2.0 pH thats pretty Low! Like I told you pH is a funny thing. I talked to our senior plant chemist about it and he agreed that it should be around true 5 mabey as low as 4.5 What kind of ph meter do you have? I am curious why you changing probes so often? Does yours use potassium chloride in the probe(conditioner)Do you standard your pH meter out with known buffers, say like 4.0-7.0-10.0. Also do you keep your probe clean and in clean water(Demin water) when not in use? Them things I just told you would all affect the way your meter reads. I left my e-mail this time so you can get ahold of me for anything. I also would like to pick your brain about some tanning methods. Thanks Roger

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