---NT--- wrote:
Huh! I woulda thought that would scar the vinyl. Or does it and they just buff it out while it's still warm. Interesting, either way.
But I guess I'll have to use 2 part molds - everything I hope to do will be rigid (plaster, resin, metal). Woulda been nice if there was some secret magic trick to using a 1 part mold for a rigid cast (without destroying the mold to receive the casting)!
Here's another idea I've been thinking of: Sculpting your piece, creating a two part mold and then casting multiples in wax. Clean up the wax casts so there aren't any seams, etc and then create multiple 1 part plaster molds from the wax casts. With the multiple molds you can then make a single cast out of each plaster mold - destroy the mold to retrieve the cast. I don't know if all the work to create multiple waxes and molds would be worth the end results - but as you can tell, I'm trying to think of ways to use 1 part molds and still be able to create multiples.
If you have a good silicone mold to begin with, it should be pretty straightforward to pour up a great number of wax models. This is what I am hoping to do so that I can continue sculpting revisions, and then bring the piece to final refinement and smoothness.
The one part plaster molds sound feasible, but I am wondering what advantage they would pose for your project. We do this kind of stuff with dental work all the time, but then you either have to use an air-chisel, or bead-blaster to de-vest the work (and obviously both entail hazards of damage to your piece---altered textures or accidental fractures). You would probably need a really good separating agent, and even then you would probably get adhesion in little interstitial spaces.
If you were going to use something rigid like resin, what about simply pouring up some models in a silicone mold?
Here are some pictures of pulling a toy out of a Japanese slush mold:
Because the material has "memory" after it has been formed, it simply springs back to shape after it has been pulled out and cools further.
