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Bad African Skins-Why No Stretch?

Discussion in 'Tanning' started by Rhino, Oct 17, 2009.

  1. topnotch

    topnotch Member

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    is there any way to rehydrate a cape like this or is it hopeless, a customer brought in a black wildebeest that was wet tanned in america and there is absolutley no stretch to it, no way its going around the form, atleast 5 inches short through most of the back. i talked with the tannery and they said soak it in saltwater but that didnt do anything. they had no other advice, has anyone found anyway or anything to put enough stretch in one of these capes to make it possible to mount.
    thanks
    tyler
     
  2. cyclone

    cyclone Posts: 400001

    Unwinding of the triple helix....this can be caused by acid swell as you have already stated. It can also be caused by base swelling as in de-hairing solutions and by enzymatic action...
     

  3. nez

    nez New Member

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    The Wildlife Gallery tells me that they can sometimes do a "re-tan" on those card board tanned skins from Africa with some success. Any thoughts. Is it a crap shoot not worth trying. $$$$$ could ad up as the Wildlife gallery charges the full tanning charges.
     
  4. *

    * Liberalism IS A MENTAL ILLNESS !

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    Nez, SO if you get a cardbord tanned skin from WG, CAN THEY re tan their own ;D ::) ::) ::)
     
  5. Bill Yox

    Bill Yox Well-Known Member

    I just mounted some african mounts tanned at Carolina by oldshaver and co...they were some of the finest skins Ive ever mounted, african or anywhere. I VERY seldom mention tanneries, and I know of a few very good ones. I also know of too many bad ones, regardless of their ad claims.
     
  6. Rhino

    Rhino Too many irons in the fire will put the fire out!

    Thanks Bill. Rick will appreciate that!

    Nez, if the skins, were TANNED in Africa, there is a good chance, they can be re-tanned, to your liking.

    The key word, is TANNED. If they were tanned in African, chances are, they can be re-tanned here, to yield a better product, if they didn't screw the pooch? The skins they tan there, are usually "FRESH" skins, and wont end up un-mountable, BUT, they always need more work, to meet our standards!

    In my opinion, THEY ARE LEARNING! I have seen alot of re-tans from Africa, and over the years, they are getting better! I saw a giraffe cape today, that was tanned in Africa, that needed JUST A LITTLE touching up, to yield a GOOD product!

    With the prices going up on everything here, I THINK, that the BIG Taxidermist, depending on AFRICAN mounts for income, is going to start feeling the pain, within the next 3 years. They are SLOWLY getting their 5hit together over there, and I feel, THE AFRICAN HUNTER, will also SLOWLY realise this. OUR USA hunters are going to start practicing a little, "one stop shopping"? Everyone is after the SAME dollar! There are a few Taxidermists, and a few TANNERS, from the good old USA, making MORE trips to AFRICA, with every year that passes.

    Have a good evening
     
  7. BDrake

    BDrake Active Member

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    My 15 African skins arrived at Carolina this past week. I saw the outfitters process, the skins were well cared for, they were buried in salt, inside a large building. They wanted me to tan the skins there but it was an alum tan and they said the skins would arrive hard and would have to be soaked up in oilto soften.
     
  8. Glen Conley

    Glen Conley KARMA GOOSE R.I.P. 2006-2006

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    Cyclone, here's some food for thought. The two photos tagged as your's for the time, the skin photographed was burned up big time with the help of citric acid. In the two photos it appears as if the proteins have dissolved, and then fused back together. Now, I am throwing in another
    photo of the same piece of skin, BUT after I had worked the elfin magic.

    Look close! It's collagen, but there is not a triple helix making the structure.

    Throw out any kind of thoughts you might have. For you other folks in learning mode, the skin can not take on any more "agents" when it is in this swollen, saturated state.
     

    Attached Files:

  9. Glen Conley

    Glen Conley KARMA GOOSE R.I.P. 2006-2006

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    We have to keep track of this thread, it needs some additions.
     
  10. cyclone

    cyclone Posts: 400001

    Sorry, but I don't see it Glen. My eye is not trained for microscopy. If I look closely, a little less than halfway up the pic directly above the "C" in your last name...I see a fat strand that appears to be wound of multiple strands..I see this throughout the photo.

    What are we looking for?
     
  11. Glen Conley

    Glen Conley KARMA GOOSE R.I.P. 2006-2006

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    Cyclone, some of your written replies have been on the money, phrases like the unwinding of the triple helix is one such.

    Anyone that has ever seen a good, cleaned off section of collagen has pretty well used the comparison of a three strand cotton rope. The three strands can be unwound, then each of the single strands can be unwound down to the point of a single strand. The thing that all of these strands will have in common is that they will all have the same appearance structurally. Some where buried in the books at home, there is an electron microscopy photo of a single collagen structure. It doesn't look much different than the photos I show with a compound scope.
    If I ever come across it again, it will show up on taxi.net.

    How accurate is the copy and paste old shaver published? How accurate is the article about the effects of salt on cellular material? That article describes how dna is removed from salt cured skins. How in thee Hell can dna still be present if the nucleic material has been leeched out with salting? Does that mean salt cured proteins are stuck like glue?

    I have thought about some kind of poll around these microphotographs to see how many people are following the illustrations.
     
  12. Rhino

    Rhino Too many irons in the fire will put the fire out!

    Still reading, Glen! You have fun dude! I now you love it, and I love reading it! Im just glad to see you back in FULL force!
     
  13. cyclone

    cyclone Posts: 400001

    If it is salt cured and not re-hydrated much of the DNA should still be within the structure, although the cells may be lysed, shriveled, or destroyed.. Where can it go if the hide is not re-hydrated and washed? This is why I preach the importance of "proper" re-hydration..Not to remove the DNA in particular, but to remove all of the other "gunk" that we don't need...

    You should be familiar with the Hofmeister series?
    http://en.wikipedia.org/wiki/Hofmeister_series


    My belief is that salt curing lessens the chances of proteins gluing together...

    We've now come full circle back to the original subject of this thread...I believe that air drying or sun drying leads to very strong gluing bonds of the proteins....
     
  14. Glen Conley

    Glen Conley KARMA GOOSE R.I.P. 2006-2006

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    Now hold on there, oldshaver, I was going to go until I got stuck, or ran out of answers, then I was going to hand off to one of you guys. Right now we are working with cyclone’s photos before we come back to your’s.

    Cyclone quote, “You should be familiar with the Hofmeister series?”
    Nope. That’s why I handed off to you. That just adds a whole lot to the mix.

    Cyclone quote, “If it is salt cured and not re-hydrated much of the DNA should still be within the structure, although the cells may be lysed, shriveled, or destroyed.. Where can it go if the hide is not re-hydrated and washed? This is why I preach the importance of "proper" re-hydration..Not to remove the DNA in particular, but to remove all of the other "gunk" that we don't need...”

    One thing I have questioned is the importance of all the other gunk when a skin is subjected to various tanning techniques and materials. They ARE NOT the same at microscopic levels. They CAN and WILL show different properties. Leather boot soles, leather boot uppers, they can come off the same beef, but it takes different techniques and materials to “get it there”.

    Cyclone quote, “My belief is that salt curing lessens the chances of proteins gluing together...”. I would have to agree to that from the standpoint of a salt molecule will have taken an available bond.

    Cyclone quote, “We've now come full circle back to the original subject of this thread...I believe that air drying or sun drying leads to very strong gluing bonds of the proteins....”. What we have to question is, “Which proteins?”. We have just about turned proteins into indefinite nouns.

    Before I leave this thread for the time, if a person wanted to remove all the other gunk from the skin, it’s really simple. Use one pound of salt to a gallon of water, add enough acid to take the pH to 6.0. Allow a 15-20 minute soak for each soak. Repeat until the water is clear after using. This will not only clean the collagen fibers, but you also get a good safe cleaning of the hair side. If you used STOP-ROT up front, cleaning will be faster and more efficient. This technique opens up more possibilities in conjunction with existing products.

    One thing we have to keep in mind, Tanneries, and Bucket Tanners are two different animals, with "some" shared techniques.
     
  15. cyclone

    cyclone Posts: 400001

    Salt crystal, not molecule... remember it's totally ionic..in water it completely hydrolizes to sodium and chloride ions...one positively charged, the other negative. Each ion will find an opposite charge in the collagen lattice to cling onto...

    So how long have you been doing chemistry Glen...You describe a method for liquid/solid extractions... BTW at this point I run my hides out to my beam and 'squeegie' a lot of that gunk out of them with the edge of my blade.....


    A point to well remember...
     
  16. Monte

    Monte Missouri fur-Limited hair-tanning

    maybe you can squeegee them out with the chemical process??? Swell it up then schrink it back down. That's what I do in the leather bean house. Yes, we can do it with hair-on as well.
     
  17. cyclone

    cyclone Posts: 400001

    Monte....A lot of the gunk removal for big tanners is accomplished in their paddle vats.. I don't know if you all paddle when re-hydrating or not but a lot would be removed in this step...

    Being a "bucket tanner" my pickles are static...I do hand agitate during re-hydration and wash prior to the pickle and I can tell you that much of the gunk is removed...

    Folks that power wash their hides will also remove a lot of that gunk....I haven't tried it but know it would work. What I'd really like to try is power washing with salt water...Probably wouldn't be healthy for the power washer, but should really "open up" a hide's structure.
     
  18. Monte

    Monte Missouri fur-Limited hair-tanning

    I only use wet drums. Run cycles start out at 5 min per hour and increase to 20 min per hour in the rehydration cycle (most african are static soaked first , from 1-7 days or more with no problem slipping. Use formaldahyde in small amount as a disinfectant, no bacteria. Salt is there from the dry salted hides.
    I also wash after pickle and tan with warmer water. Put rinse doors on the drum, 2in water line at 50-70 psi line pressure, 20 min. rinse again.. I never have used as much chemicals as others have .

    that bucket tanning will wear your butt out.
    Also pressure washed a grease burned fat zoo cat that had been through the pickle and did not fall apart. It did wonders for cleaning it up . I froze it and will work on it again soon. I think I will save it.
     
  19. I totally agree regarding the problem of drying skins in the sun especially on a concrete floor as well. The skin gets baked from both ends and you will sit with slip as well.
    I am sure that only the sour grapes and rotten appleas gets the attention. I am as lo sure that there are village people in the good old USA as well!
    There is another problem that one needs to deal with here in Africa and that is the salt. Some salt have too much lime in it. That causes another problem that we need to deal with. If you get skins and the salt looks like amber you know you are in for some fun.
    Cheers.
    I will have a cold one tonight around the fire with a nice steak BBQ on a hardwood fire, and I will think of you poor sods in the USA.