I have heard that alum can be used as a preservative.... but I don't know where to find it.
Anyone here familiar with alum?
Thanks in advance!
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Alum is a pretty general term for metallic sulfates. Some are used in tanning while others are more common in pickled cucumbers. Alum as a common name can be found in most big grocery stores and farm stores in the home canning/pickling section.
In and of itself, I don't think it has any preserving ability. Used as a pickle solution or a tanning solution goes in a different category than you seem to be implying. Some dry preservatives contain small amounts of alum just for the constricting induction of the cell structure. What exact information are you looking for? There are lots of tanning gurus here that can fill you in on alum tans and tanning.
Having been in the business for more than 20 years, I've seen many things come and go and come back again. The popular use of alum as a tanning agent is not something I want to see revived. Alum tanning use to be popular as a home tanning technique. The alum was mixed with a salt brine and the skins were soaked for up to 2 weeks to ensure complete penetration. The upside is it is a very cheap and easy tan and the leather is a nice white color. The down side is the skins SHRINK badly in the tan and shrink even more after the skin is mounted. 20" deer capes magically turn into 17" capes. Also, alum tanned skins have a tendency to deteriorate over time and will actually disintegrate if exposed to any moisture including humidity in the air. Alum brines are not a true tan but are actually a preparation similar to a pickle and there is no permanent bonding of tanning agents to the skin fibers. Alum mixed with water is actually a weak sulfuric acid solution and the residual acid in the skin reacts eats away at the skin fibers over time. Use EZ Tan-100 or Liquatan. They are simple enough to use and economical to boot.
Thank you for the information. I'm not a taxidermist - I need the alum to use as a preservative in something called "salt clay" which I am making with my kids for a craft project. When I searched google for where I can find alum (I looked in the grocery store, but not in the canning section) one of the hits was this site - I guess because it has been used in the past as a preservative in taxidermy.
(another hit was the online chemistry store which will sell me a ten pound tub of the stuff for twelve dollars..... I only need a tablespoon though, so ten pounds seems a little excessive! :) )
Again, thank you for the information and I promise not to revive the use of Alum in tanning hides. :)
Patty
Does anyone know where to buy Alum in bulk? What are the different forms of alum? What is the chemical composition of alum? Thanks