No bubbles in the mix, but it bubbles in the mold, why?
Humidity, either in the air or the containers. Sometimes you can bring it back by heating the resin in a sink of hot water, then shaking the hell out of the container to kind of re-mix it, but that'll only work 2-3 times before it gets too bad to use.No bubbles in the mix, but it bubbles in the mold, why?
If what your casting can only be covered in alginate for the mold making process, my advice is to make your copy from plaster, seal it with a lacquer, then make another mold from RTV silicone, then cast resin into the RTV mold. Hope this helps.
Yeah, I suspect that is your problem, urethane feeds on water when it's curing... So you will never get a good cast out of an alginate with urethane resins...If the Instamold is the same product I'm thinking of, that's the problem. It's an alginate powder you mix with water, isn't it?[/b]
Use a better molding agent. I use GI1000 with GI179 activator from Silicones-Inc.com. The rubber must be vacuumed in a vacuum chamber but the results are worth it.