So it sounds like what you're looking for is one of the dryteks (1,2). They both use Calcium Hydroxide, which can actually be found online at many culinary websites (everyone says it's available in canning sections, but SWIM has visited every canning section within 20 miles during 3 different seasons, and they never had it).

CaOH has a very poor water solubility, which is why you use a drytek, as opposed to something like what shrabbit suggested above.

Welcome to the Nexus!

Edit: oops, missed that a1pha had linked to one of them already.