What is wrong with Alum tanning?

Submitted by Joe on 5/5/05 at 10:49 AM. ( ) 205.188.117.10

I hear lots of people on here talk poorly of Alum tanning (Krowtann & Lutan) and I don't understand the draw back of tanning with Alum products. Can someone explain? Searched the archives but didn't find what I was looking for.

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Do you really want to know?

This response submitted by George on 5/5/05 at 11:25 AM. ( georoof@aol.com ) 64.12.116.130

The story that no one wants to tell or admit it basic chemistry involved. All alums contain sulfates. Though the tan is exceptional initially with its color and stretch with little liklihood of slippage because of its astringent characteristics, it has a finite lifespan.

The alum tan deposits the sulfates (SO4) into the cell structure of the hide and it is retained there. Over the years humidity comes into play. Humidity (H20) is also introduced into the hide and the chemical compositions in combination with each other for H2SO4 or sulfuric acid. This formation ultimately destroys the hide (remember all those old paintings and fabrics are stored in ACID FREE containers? That's what acid does to the hides as well as old books, paintings and fabrics.)

Many argue they don't care as it gives them the product they desire and the customer won't live long enough to see it happen anyway. The great works in the Smithsonian Institute have disintegrated because alum was one of the first tans used. Its results are now being seen. I don't know of any work done by Hornaday that still exists because it was all done with alum (Maybe Stephen Rogers or John Janelli would know.) The tanned hides from antiquity have survived and they used brain tans and vegetable tans.

So the choice is yours, but chemistry can't be refuted in this case.


Thanks, George

This response submitted by Joe on 5/5/05 at 12:16 PM. ( ) 64.12.116.130

Thanks for your response George. So would EZ-100 by Rittel be a better choice? Does any one know the long term results of it?


Joe

This response submitted by George on 5/5/05 at 5:50 PM. ( ) 64.12.116.130

I can't speak from experience, but Bruce recommends it and he's the one who posted the information I just gave you, earlier on this forum.


In answer the origional question-

This response submitted by oldshaver on 5/5/05 at 9:01 PM. ( ) 65.190.186.115

Not a damn thing! Heres a little C&P from some of my reading material.Chemical deterioration - oxidation and acid hydrolysis Absorption of large quantities of SO2 by vegetable tanned leathers will ultimately lead to "red-rot", the irreversible shortening and embrittlement of leather fibers which causes the surface to fall away from the leather in the form of a fine, reddish powder. Vegetable tanned leather is second only to cotton and wool in its ability to absorb SO2; the presence of the condensed tannins introduced in the 19th century exacerbates this effect. Alum-tawed and chrome-tanned leathers are less affected. Photochemical attack on leather will cause bleaching, embrittlement, and even denaturation of the protein in the skin. Chemical deterioration increases the leather's vulnerability to physical damage. Source- a leather conservation conference. Joe, anyone selling syn-tans can not prove how long their tan will last, because it has not been around long enough! I would worry more about the acids you pickle with- the most popular, might not be the best. What kind of acids can pickle at such low ph's?


But OS

This response submitted by George on 5/5/05 at 10:38 PM. ( ) 205.188.116.138

That doesn't explain Hornadays mounts and because the vegetable tan ABSORBS sulfates has nothing to do with it unless sulfates are introduced to the leather AFTER it's tanned. Alum introduces it WHILE it's tanning. I'm hardly the sharpest tack in the pack when it comes to tanning, but I find it interesting that some people continue to blast vegetable tans when the word is actually a derivative of the tannic acid from tree bark. And the oldest scraps of tanned leather were tanned with vegetable tans and not alum. I think that though the process is very primal, there's still a whole lot we don't know about the actual transition from flesh to leather. Tests being conducted by Glen Conley are really showing that to be a true statement.


Nothing George don't want anyone using it.

This response submitted by Sarah on 5/6/05 at 12:13 AM. ( ) 70.178.74.104

Consider how long those mounts have been around, Mr. Roof is taking about, 100 years or so. THen ask Mr. Roof what he uses and make a comparison.

Tried and true Alum tans have been around for a long time, the glues we use have changed from the old DEXTRINE. Maybe the fact just our glues alone will make the mount last longer.

I will stick with what I know ALUM tans! We have noway of knowing if a SYN tan is going to last even twenty years, as Syn-tans are not as old as I am at age 17 now.

I tend to follow oldshaver, after reading his many post after all he is a tanner and Mr. Roof is a taxidermist.


George

This response submitted by oldshaver on 5/6/05 at 6:20 AM. ( ) 65.15.237.222

My opinion will always be that sulfuric acid pickleling is the culprit when it comes to the problems with those old mounts.


Tanning for Today

This response submitted by Bob on 5/6/05 at 8:14 AM. ( ) 152.163.100.130

I 've been using lutan -F for a long time,it gives me the kind of tan my customers like and i like.What i tan is going to last a life time or longer and really that''s all i care about.Alum tans are older than me and been producing good tans,seems like forever.Iwould only hope i could last that long . I don't think so!


Sarah

This response submitted by George on 5/6/05 at 9:11 AM. ( ) 64.12.116.130

You lose. You ARE the old grouch you don't want to emulate. I'm sure at 17 you have all the answers, but at my age, I sure don't. I just know what I've lived long enough to see. Alum was a forgotten tan during the 70's-80's and 90's but now, because of it's simplicity and availability, it has been recreated as the best thing since sliced bread. I tend to agree with OS about the sulfuric acid point. That WAS part of the scenario during the 60's and 70's but when the citric acids and formic acids became accepted, most of us using battery acids stopped. As I STATED, I think there's still an awfully lot we don't know about tanning whether we are tanners or taxidermists.


Your right George

This response submitted by oldshaver on 5/6/05 at 11:33 AM. ( ) 65.15.237.222

I no darn well I dont even come close to knowing everything about tanning. About the only thing I believe I know inside and out is shaving.


oh no say it aint so not my krowtann

This response submitted by paul e on 5/6/05 at 1:49 PM. ( amfpaul@bellsouth.net ) 65.6.78.77

i was so upset for a minute when i read all about the bad bad alum tans
what to do oh no what to do
but then i remembered
i have a alum tanned mount in my garage
and it was done in 81 or 82
still looks as ugly as the day it was mounted
by the skin is fine
oh well i guess i can relax now
and i think people thinking of using alum tanns
like krowtann can go ahead and use it like many well known experts are
i wonder about those syntanns though


Paul, ask Ken Walker

This response submitted by George on 5/6/05 at 7:05 PM. ( ) 152.163.100.130

Suddenly a few people on here think my answers aren't credible, but how about a guy like Ken. He's hardly "old" by most standards and has one helluva lot more credentials that a couple dozen of us put together. He relates that none of his early mounts, done with alum, have survived.


George, your crediblty is not in question

This response submitted by oldshaver on 5/6/05 at 8:59 PM. ( ) 65.190.186.115

This is just a disagreement. I know you know how to tan a skin, theres no question about that. Every answer you give on tanning topics, I agree with, except this one subject. I have said this more than once, but, I think we are all going to have to agree to dis-agree on this subject, or we are going nowhere fast.


Good Point OS

This response submitted by George on 5/6/05 at 9:31 PM. ( ) 64.12.116.130

And I agree. Or is it disagree? LOL


tanning

This response submitted by EJ on 5/7/05 at 12:19 AM. ( [] ) 216.114.124.121

I TAN FOR A LIVING.
PROPLE WANT NICE SOFT LEATHER. THEY COULD CARE LESS IF IT DOES NOT LAST LONGER THAN 20 YEARS. THERE IS BEAUTY IN DESTRUCTION TOO. WE ALL LIVE AND FEED ON THE DEATH OF LIFE. EVERY DARN ONE OF US. GEORGE ROOF. AND OLD SHAVER TOO. THINK ABOUT IT! IF EVERY DARN TANNED ANIMAL SKIN LASTED FOREVER WHERE WOULD WE BE?
SULFURIC ACID CAN HOLD THE PH DOWN LIKE NO OTHER. AND IT PRODUCES A SOFT SOFT TEXTURE.
IT WORKS VERY WELL WITH BRUCES EZ 100 TOO. I'VE WORKED CLOSLY WITH BRUCE AND LEARNED FROM A GUY THAT TAUGHT HIMA FEW THINGS, BACK ABOUT 15 YEAR AGO. BRUCE REPRESENTS A FINE CHEMICAL CO. SENTRY I BELIEVE. BUT EVEN BRUCES METHODS CAN BE TWEEKED TOWORK EVEN BETTER.
I HATE TO SHAKE YOU GUYS UP BUT HEAVY SHAVING IS A THING OF THE PAST. NOTHING WORSE THAN A TANNED PIECE OF LEATHER/FUR THAT FEELS LIKE A DAY OLD BEARD. IN MY OPINION. AND MANY OF MY CUSTOMERS AGREE.
HAVE A SAFE MEMORIAL.
EJ


experts help us settle this

This response submitted by paul e on 5/7/05 at 7:05 AM. ( amfpaul@bellsouth.net ) 65.6.123.189

George im not in any way questioning your credibility
you have probably forgot more than i know
but i do have a few years under my belt
i guess i really dont know the answer for sure
and i think a controlled experiment probably has not been done
for instance what type of pickle used
what type of hyde paste and so on
im open minded and still a little concerned about the whole issue
i would like to here from some experts who dont have a conflict of
interest
as for as krowtann im not even sure as to what type exactly it is
when oil is used it sure doesnt shrink like i remember the alum ones did
i would like to also know from the experts using it like
Rick Carter,Don Stevens, and Brian Harness what information they had
when deciding to use it
id have a hard time believing these guys used it without feeling it was safe
so how about it experts out there give us lil guys some input

p.s.George when are we getting the ballets
i decided to join the NTA and am looking fwd to voting for you
even though we disagree on a few things i think your the right man for the job


Paul, Ballots should be at the CPA

This response submitted by George on 5/7/05 at 9:03 AM. ( ) 64.12.116.130

The "drop dead" date was May 1 for the electorate. All the ballots are controlled by a contracted certified public accountant who mails them out and, in turn, receives and tabulates them. The results are then kept sealed and are FEDEX overnight mailed to the NTA convention site. The executive director receives them the day of the membership meeting, opens the sealed envelope at that meeting, and reads the results live. At one time, only the winners were announced in a mannerly attempt to avoid embarrassment to the losers. HOWEVER, because of the usual accusations of "hiding something", the actual vote counts are now disclosed and published.


Psssst........a little secret!

This response submitted by Bruce Rittel on 5/7/05 at 3:37 PM. ( rittel@mindspring.com ) 207.69.137.201

Just for the record - I started selling EZ-100 (a Syntan) 26 yearsago! Those skins are still as strong and durable as they were then. No acid rot - no weakness - no tearing at the seams - no discoloration - and guess what? They can still be washed! Over and Over! Off hand I'd say 26 years is a long time! But just to prove a point - if you have a 26 year old Alum tanned skin - try washing it in your wash machine on gentle, luke warm water and using a mild detergent. Make sure its a skin you can afford to LOSE!


Thank you Bruce

This response submitted by George on 5/7/05 at 11:08 PM. ( ) 64.12.116.130

I was getting tired of fighting this one and needed the reinforcements. LOL. OK, I feel better now as I'm not the only one who's "opinionated".


Thats just my point

This response submitted by oldshaver on 5/8/05 at 9:20 AM. ( ) 65.190.186.115

We are in the Taxidermy service business. Why is there a need for washing skins that are going to be mounted? Alum holds in a curl test up to 130-140 degrees. Why would you need higher temps than that for Taxidermy purposes? The only thing a curl test proves, is the ammount of hot water a piece of skin can stand before the tan washes out. EZ 100 washes out around 165 degrees, if I remember Bruces figure corectly.(a few months back). This has nothing to do with the longevity of a mounted specimen in someones climate controled home. There are many fine examples of alum tawed artifacts dating back from mid-evil times, and that is a fact. Bruce, isnt safe-form acid the same thing as safety acid? Correct me if I am wrong, but safe-form acid is considered a "safe" form of sulphuric acid. I would worry more about using sulphuric acid anyday, than using alum. How was hydrocloric acid first discovered? By distilling sulphuric acid and salt. (distilling-removing water) Got to go to Church, will get back to yall later.


OS your point is valid to a degree

This response submitted by George on 5/8/05 at 9:45 AM. ( ) 152.163.100.130

On mounted specimen, it's unlikely that water will enter the equation and, as Sarah said, maybe the glues are the key there. HOWEVER, as taxidermists, we also supply hanging hides as well as rugs. Both of these have ready access to spills as well as no support underneath to protect them in the event that water might contact them. Bear rugs, especially, have always been a worry of mine with alum tans.


I disagree about our customers!

This response submitted by Bruce Rittel on 5/8/05 at 8:36 PM. ( rittel@mindspring.com ) 207.69.138.204

Our mounts can be placed by the customer in leaky hunting cabins, above a roaring hot fireplace, in a moist, hot attic, a cold moist garage, even outside or in the case of rugs, on a damp floor. Very few of our mounts find themselves in a humidity controlled environment, unless they are lucky enough to find themselves in a collection.

And while you may not consider the Shrinkage Temp important from a Taxidermy point of view - it does determine whether or not if the customer trys to wash their keepsake, it will fall apart or not. The Ts determines how strong the bond of the chemicals are that were used to tan the skin. Another aspect of this is also the reactive sites left in the skin when its finished. Obviously if contains reactive sites and is not strongly stabilized it has the capability of reacting with things like moisture and recombining into acid again. If the chemicals are only weakly bonded - the bond can be broken by the introduction of moisture. This is typical of Alum.

Using Sulphuric Acid with EZ-100 is not a problem. While I dont use Sulphuric Acid, because I prefer Saftee Acid, its like Saftee Acid in that it's simply a pickling acid, that helps us prepare the fibers, and adjusts the PH prior to tanning. Neutralization eliminates the bulk of any residual left behind by the acid. Once the skin is exposed to EZ-100 the tanning agent stabilizes the acid and forms a strong bond with the fibers. There should be no active reactive sites within the fibers to draw moisture or react with other chemicals. The same is true of a Chrome Tan. Sulphuric Acid is used extensively in the Chrome Tan tanning industry.


good information ill try ez100 this year also

This response submitted by paul e on 5/9/05 at 7:16 AM. ( amfpaul@bellsouth.net ) 65.6.117.162

im not convinced how much if any harm wil come to a head that is just going to be a shoulder mount with krowtann
but i think youve(Bruce) swayed me to the point ill try ez100
for rugs and such and ill try a mount or two also
i also want to give the Whitetail Designer Systems a try
good discussions
but i would like to here from the experts using krowtann to give their input why they think its safe
as for as a pure alum tann ill probably leave that stuff alone
from now on


I suppose I'll find out just how well alum works

This response submitted by DZ on 5/13/05 at 2:32 AM. ( dzenga2002@yahoo.com ) 198.22.21.50

I am having a vest made out of a large boa hide that was tanned about 15 years ago using a sulfuric acid bath at a deer processing business that I use to work at. The hide is still in great shape, however, I've just started back tanning hides at home (for my own personal use) and so far I've alum tanned a nutria. It turned out very well although I got a little carried away during fleshing and cut a few small holes (it's been awhile sinse I've tanned anything). It doesn't matter, the hide was very inexpensive to tan. On the other hand, I have three snake hides (rhino viper, puff adder and black spitting cobra) in an alum pickle bath that I'm going to have a bikini made for my fiance`. I'm a little worried that they may not hold up even though the bikini will be for sunbathing and not swimming. These hides, needless to say, aren't as easy to replace as the nutria. Can anyone offer me any advice? Did I screw up? Thanks


No-your alright

This response submitted by oldshaver on 5/13/05 at 8:55 PM. ( ) 65.190.186.115

Sweat wont hurt it, but with this post, your killin me!LOL


Tannning solution for Snake Bikini

This response submitted by David Patton on 5/15/05 at 7:12 AM. ( ) 12.76.209.65

DZ,
We market the best solution for the little horny, swelling, spitting snake bikini you are proposing.

First you crush up 2 lbs of Viagra......


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