Bad African Skins-Why No Stretch?

[cyclone]

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?

[Glen Conley]

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.

[oldshaver]

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!

[cyclone]

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?

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

Does that mean salt cured proteins are stuck like glue?

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....

[Glen Conley]

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.
   

[cyclone]

I would have to agree to that from the standpoint of a salt molecule will have taken an available bond.

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...
    

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.

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.....

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

A point to well remember...
   

[Monte]

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.

[cyclone]

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.

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.

[Monte]

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.

[huntertaxi]

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.