Re: gum preservatves
On Thu, 4 Sep 2008, Mark MacKenzie wrote:
What you describe is often used as a "classic" catalyst for polyester monomers in order to create a solid reacted resin. The dimethyl pthalate is a plasticizer for many resins. As you suspected, neither of these are preservatives. The MEK peroxide is closer to rocket fuel as a matter of fact.You guys sure know how to terrify a simple civilian... Now I'll probably just leave it there until it explodes and blows up the whole block !!!
I'll add, however, that I myself don't at this point use any preservatives, because I prefer "lithographer's gum" -- or whatever it's called, premixed, with the poison already in it... In fact I'm surprised at how many folks do mix their own.... For a long time I could pick up a gallon at a commercial printers' supply house on 22nd Street... That area is of course now the Chelsea gallery district, so nothing of the sort remains. I still have a supply from Daniel Smith, and after that, who knows? (I suspect many of the best commercial gum arabics, made for high speed printing presses, are no longer made, since it's probably all digital, or anyway something or other else. But I didn't get to that bridge yet...)
Those commercial gums, by the way, seem to keep forever. I've kept some favorites for years and they still work. (They do darken, or "oxidize", but that seems not to affect the print.)
Meanwhile, and needless to say, thanks for the warning....
As for a preservative, if you like the thought of essential oils have you tried clove oil? This was used and is used for preserving things like hot hide glue so that it doesn't "go off" quite so quickly. As I am not a gum printer (yet) I can't say that it would work for you.