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What makes in house tanning diff from a tannery?

Discussion in 'Tanning' started by rarestjewels, Dec 6, 2009.

  1. Steve Rotramel

    Steve Rotramel We got some radical rebels in this county!

    I know you better than you know yourself.

  2. If you agree that

    "I would say that in a fresh hide the fibrils are about as spread apart as they are going to get."

    Then were is there room for the tanning agent? As an example; wet sponge can only hold so much.

    How can you force or "pressure" more into it?

    In part you adress this question in your reply saying

    "while it transfers pressure on a near 100% efficiency rate, it is not compressible as you know. Therefore, the overall effect of the pressure is partially nullified."

    While i agree fresh water in the hide "dilutes the chemical mix" i am not sure at all that the effect it would be substantially measureable.

    I do agree with the statement you made, when you said

    "As you know, a primarily alum based tan penetrates on a reactant concentration basis. If the concentration goes down in the drum, less gets into the skin.

    This is were vigialnt and consistant readings need to be taken and recorded to assure that the concetration levels are adjusted and maintained

    I will partially agree with you when you say,

    "The fluid in a fresh hide is not "water". It behaves differently than water. One of the differences is how effective the chemical "pull" is."

    Qulaified because our bodies are largely or mostly water since 98% of our bodies are in fact water, now it may not be fresh water from a well or tapwater since it has in it has other substances and chemical attributes as a result of the host ingesting the water. i am not sure at all that "Difference" on chemical pull is measureable.

    We are of the belief that we want the biological fluids removed, with the the integrity and structure maintianed.

    At the risk of being overly simplified we are using chemistry to "wring the biological out of the hide" as if you were wringing out a wet sponge. and then drying the sponge out to the lowest point of humidity possible the sponge is now smaller than when you first started. We believe that salt drying the hide and and heat with low humidity is the best way to do that. Back the sponge example... it is then wet back in the rehydration process...so now the sponge is the same size it was before, with alot less of the biological material that was removed in the salting and drying. Then when placed into a concentration of tan, through laws of osmosis.

    {Since some people reading this may not know the definition or understand the concept here they are; Definition first: Diffusion of fluid through a semipermeable membrane from a solution with a low solute concentration to a solution with a higher solute concentration until there is an equal concentration of fluid on both sides of the membrane.
    Concept: The term osmosis describes the movement of a solvent through a semipermeable membrane from a less concentrated solution to a more concentrated one. Water is sometimes called "the perfect solvent," and tissue (for example, a cell walls) is the best example of a semipermeable membrane.}

    On many levels Steve we are close to the same page with you, The laws of osmosis occur naturally without any pressure being applied, it migrates from a higher concentration to a lower one untill they have equalized. This is occuring countless of trillions of times every day in nature; for the purposes of tanning as long as the concentration levels of the tan is sufficent it will happen all by itself and you will have a "tanned hide".

    Here is where I am not able to connect to your points on your process, if its going to happen naturally anyways what is the advantage of or how does creating an equalized pressure on a soluotion in a sealed container make it better?

    You yourself said "... it is not compressible as you know. Therefore, the overall effect of the pressure is partially nullified."

    Since its not compressible its not "partially nullified" it is completly nullified.

    If it was a gas i can see where the pressure might penetrate more effectively as long as the cell membrane wasnt ruptured in the process, but in a liquid in a sealed container how could it have a measureable difference. The pressure is being applied evenly on all surfaces and so it has to cancel itself out.

    It is a law of physics for every action there is a reaction, but when equal pressure is applied on every surface equally there is no action it is stagnant.

  3. Steve Rotramel

    Steve Rotramel We got some radical rebels in this county!

    Well said Bob. The only thing I would point out that you didn't consider is that the saturation of the skin is never 100%, nor is the machine ever 100% full. Therefore, the effect of the pressure is not completely nullified.

    I like your sponge example. I've used it relative to pH and bonding. An alum pickle (ph below 3) renders almost no tannage even though the chemical penetrates very quickly. And sets the hair better than anything I might add.

    It's like a white sponge in cold red die. Remove the sponge and rinse and the sponge is still white. Bring the temp up to near boil and the sponge is red forever.

    Same with the pH in an alum tanned skin. The chemical penetrates quickly at the low pH but no bonding occurs until the pH comes up. The higher the pH (within limits) the better the bonding and less washout, less shrinkage on a form, or softer break in a rug.

    Also I've heard the "We are 98% water" thing my whole life and I think I've read the number is closer to 70%. But that has nothing to do with the discussion.

    Here is why it's better. For a taxidermist, it gives the added measure of penetration speed needed to set the hair without salting. Less steps - less hazards.

    Many of our customers will testify that at least once or twice a year they use the machine to save a cape or hide that would never have survived fleshing, salting, drying,rehydration, etc. etc. I myself have held many capes in my hadns that I knew positively would come back slipped if sent to a tannery. In the automatic tanner the hair gets set, the skin gets tanned, and the animal gets mounted.

    It's better for that reason. Not necessarily better leather, and I never claimed better leather. It's a better system for many taxidermists.
  4. Steve, its hard to say what can and cant be saved before tanning, i will say if the hair is falling out before you get started i wouldnt waste my time; cause you cant reverse any damage thats already been done.

    While i am sure people will say or claim it "saved" a cape...that presumes that it couldnt have been tanned without using this process and i am not entirely convinced that is true.

    Still not on board with all of your science on this topic.... and briefly here is why...if the tank is not full and has air in it ... and since air is less dense than liquid ... and because air is less dense than a liquid or a solid the only thing i can see possibly being pressured into the cape would be air <gas> not tanning solution which is a liquid.

    As an example:

    When a scuba diver goes underwater to any measureable depth the weight of the water creates pressure on the water surrounding him, this pressure presses nitrogen, out of the water < in the form of a gas> not a liquid, into his body. Again it is the law of osmosis at work, the concentration of nitrogen in the form of a gas being higher in the water than in the body prior to him entering the water, and the gas being less dense than the cells of the skin being permeable which allows the gas to be forced into the body. The pressure from the water does not force liquids or solids inot his skin only gas because the gas has a lower density.
  5. George

    George The older I get, the better I was.

    LOL Well, at least we know your intelligence is far exceeded by your ego then.
  6. Steve Rotramel

    Steve Rotramel We got some radical rebels in this county!

    "Steve, its hard to say what can and cant be saved before tanning, i will say if the hair is falling out before you get started i wouldnt waste my time; cause you cant reverse any damage thats already been done.

    While i am sure people will say or claim it "saved" a cape...that presumes that it couldnt have been tanned without using this process and i am not entirely convinced that is true"

    Well, it isn't hard for me to say and I'm 100% convinced. Where the capes are lost at the tannery is in the soak-up as you well know. A cape that is green and stinking and shedding hair, as you said, is usually not worth the trouble. This machine will save those capes as proven literally thousands of times.

    And the pressure doesn't force fluid into the skin. It cause more surface contact between the dissolved chemicals and the fibers of the skin, thus increasing their reaction rates.

    You didn't address whether osmotic pressure moves fluid or chemical. Not that it matters in this case but it is an interesting question.
  7. Steve Rotramel

    Steve Rotramel We got some radical rebels in this county!

    I've often pondered that question myself - which is bigger, my ego or my intelligence? I end at a loss because I know only a greater mind than mine can give the answer. Alas.....
  8. George

    George The older I get, the better I was.

    LMAO I love you Steve. You're a superb debator. WRONG, but still good. LOL
  9. Steve Rotramel

    Steve Rotramel We got some radical rebels in this county!

    LOL! - Trickery! LOL - George that was about as disorienting as anything you've ever said!
  10. Hartung

    Hartung New Member


    May a simple brain“tanner“ throw in a thought in this debate? Isn’t the main question here about if an “autotanner” produces a real tan or if it doesn’t? That is if the product coming out of the “autotanner” is leather or is not leather?

    Leather is characterised, amongst others, by an elevated shrinking temperature compared to the raw skin. I’m sure you must have an institution in the US that is capable of analysing any piece of leather send to them and to definitely state if the product can be called leather or not.

    It Europe we have at least one institution that I know of that does such evaluations even on Palaeolithic leather. They can even analyse how the leather has been tanned. So why don’t you just send several “autotanned” pieces out to have it analysed. That would could short in one way or the other and once at for all any autotanner dispute.

    Just a thought …
  11. Steve I am still not seeing how it will "cause more surfcae contact". Can you explain this better?

    as for your second question i wasnt choosing to ignore it the first time you brought it up but i chalked it up to a mistatement and wasnt going to pursue it.

    Osmotic pressure does not move chemical or fluid so the anwer is it does neither.

    Osmatic presure is "the pressure needed to PREVENT the osmotic movement of water or another solvent though a semipermeable membrane" refrence http://www.answers.com/topic/turgor

    "Osmotic pressure is the pressure that must be applied to a solution to prevent the inward flow of water across a semipermeable membrane.......The osmotic pressure is defined to be the pressure required to maintain an equilibrium, with no net movement of solvent. " refrence http://en.wikipedia.org/?title=Osmotic
  12. coonhollow

    coonhollow Active Member

    for the amount of skins that you can do at a time in an "autotanner" and the amount you can tan in a vat...I can still tan more in less time. The auto tanner is and should always be on the Dan Rhinehart infomercial website. It reminds me of the "Pet Rock" you can tan without a household water storage tank and a compressor.
  13. Steve Rotramel

    Steve Rotramel We got some radical rebels in this county!

    Well, I'm not sure I can. There is always a point where where any physical process becomes magic. It makes sense to me though.

    We know that all molecules are composed of a nucleus and a set number of electron orbits. The outer orbits are what make contact and bonds with other molecules. It's interesting that the solar system-like pictures of molecules that we see are not at all accurate. The fact is that if you had a simple atom blown up until the nucleus was the size of a tennis ball, the first electron orbit would be about 800 miles away, and the electron still would have no mass.

    So everything solid is over 99.9999999999999 (keep going) per cent space.

    The molecules themselves are loosely bonded and chemical reactions happen when they collide with each other. The theory states that under pressure, more molecular collisions occur creating possible bonding situations. Is that because of increased molecular movement? Closer proximity? Combination of the two?

    So the law of osmosis demands equilibrium. I understand the backwards method of defining the law, but movement of fluid is required to achieve that equilibrium. Since in our situation there are no membranes being breached (unless you are calling the entire skin the membrane), what is being moved? If only fluid, how does the chemical get to the other side of the skin?
  14. Kevin M.

    Kevin M. Active Member

    But for those of us that just need to tan 1 or 2 pieces a week. It is a wonderful piece of equipment.
  15. coonhollow

    coonhollow Active Member

  16. Monte

    Monte Missouri fur-Limited hair-tanning

    If the electrical charge of the collegan is not correct , no amount of pressure will lower the surface tension and allow the tanning agent to be attracted to the tannable site. In my opinion pH is what I use to change the condition of the skin. I can swell it or shrink it. If a lime streak is left in the middle of a thick hide nothing will allow penetration of the pickle or the tanning agent until you first address the difference in the pH in the middle of the hide. For soft stretchy leather and hair-on I want to open up the hide and get rid of all the crap. So the tanning and oiling will have the best effect. Our multi step process is required to achieve the results I desire.

    I am stilll comparing commercial to in house tanning. That was the question.

    pre-salting is required to kill the portion of the hide that hide glue is made from (keeping this in laymens terms). Salting can be achieved by dry salt or by salt brine curing.

    There is nothing wrong with starting with a raw skin if you know what you are going to do later that will satisfy the requirments of properly charging the collegan later. Here is how it works for the leather chemist who is starting with raw versus salted.
    The raw skins are always washed until the water is clear.
    The hair is removed with sulfide and lime. once again washed, refloated and limed from a few hours to a few days depending on the type of finished leather desired.
    After liming the bating is done, washed out and the float and hides are ready for the pickle. Prior to adding the acid the salt is added and a min. run of 20 minutes to allow the salt to dislove and penetrate the skin. Then the acid is fed in slowly over 45min to 1 hr. Total pickle time 1.5-2.0 hours
    You see the liming , bating and salting and pickling are all done before the tanning agent is added. Since liming is not used for hair-on taxidermy tanning , pre salting is required, either dry or brine. Note: dry salting will not penetrate deeper than 1/4 inch. I have lab results that will prove this. It takes 8 hours in a raceway for a 50 lb. cowhide to salt cure for short or extended storage and too kill the glue.

    Some of you may be just lubricating raw collegan, because you mount the capes wet. However, if you are satisfied then I am not trying to change what you are doing.
  17. Kevin M.

    Kevin M. Active Member

    You should only speak after you know what you are talking about. I've had my tanner for 6 years or so. And it ways $859.00 . You can get one today for $1200 or so. Mine has paid for itself many times over.
    And if you buy your chemicals and oil smart. It's about $2.
  18. George

    George The older I get, the better I was.

    Kevin, if it paid for itself, why are you claiming it cost $859? You obviously got it for free.
  19. Kevin M.

    Kevin M. Active Member

    Well George. Everybody knows that. That means. The money you saved went towards paying for the machine. I'm sorry that is too simple for you to understand !!
    But if you must know !! Accually, I did get it, My bird flesher,Dakota Flesher. And tumbler all for free. When VOC - REHAB sent me to taxidermy school. They also paid for my eguipment. But the Price of it at that time was $859. Had I had to pay for it. Thank you for asking !!
  20. George

    George The older I get, the better I was.

    OHHH, so now we see that you didn't pay for it at all. Well damn, if someone would give me one I might try it too. And it sure would be the best thing since a popup toaster when I got it.

    Kevin, you need to stop. If you only did one or two hides a week or a month, DP would save you much more money HAD YOU HAD TO BUY THE UNIT. So you like it and you like the product. We already got that part.