Mercuric Chloride

[Pete Watkins]

I intend to try my hand at Gum Bichromate in the not too distant future. I've read a couple of books (The Gum Bichromate Book and Beyond Monochrome) and they both recommend using Metcuric Chloride in the formulas. I've traced a possible supplier here in The U.K. and wonder if any of the Gum Bichromate users here use the stuff. Don't tell me about the dangers, I know about them.
Best wishes,
Pete.

[BarryS]

Hi Pete--I do gum printing and have a number of friends that also gum print--and none of us uses mercuric chloride as a gum preservative. There are other cheaper safer alternatives that work just as well. I use sodium benzoate, and it works really well preserving gum solutions.

[Sevo]

If it must be a mercury salt preservative, use thiomersal - in terms of efficiency vs. toxicity it is more benign than mercuric chloride, and it was generally used as a replacement for the latter in commercial preparations from the fifties until they went over to even less dangerous preservatives some twenty or thirty years ago. Small amounts might still be legal to purchase and own without license. But there are plenty of more harmless alternatives.

[PViapiano]

Don't use it, don't need it...what about thymol or equivalent?

Better yet, buy your gum from Daniel Smith or the Formulary...works great and it's taken care of for you.

[neil poulsen]

If not for you, for general information, this stuff is off the charts on toxicity. Only a small quantity can be fatal, and I've heard that it can be absorbed through the skin. I wouldn't go near it or have it in my house. It is deadly.

For more information on this compound, contact Bostick and Sullivan.

http://www.bostick-sullivan.com/contact.php

[Pete Watkins]

Thanks to everybody who replied. Barry, could you tell me how to use Sodium Benzoate as a preservative, the formula that you use etc.?
Thanks again,
Pete.

[BarryS]

Pete-- I'm pretty sure I use a final concentration of .5% (5g/L) sodium benzoate. Dissolve a concentrated solution of sodium benzoate in water like 10% (1 gm/10ml H2O) and add 5ml to a liter of gum arabic solution.

[Pete Watkins]

Many thanks Barry, I'll give it a try.
Pete.

[reyno bundit]

i use tea tree oil as a preservative, just a drop or two to a 30ml 1-1 solution