question about mold building medium

[EvilNinjaChris]

I was in a craft store the other day and noticed a little jar called mold builder...aparently its liquid latex. I have heard of using this a s a mask for airbrushing/painting but could you use it instead of silicone for a mold? anyone try this or is there a reason why it wouldn't work?

[Tommy Allison]

The minute you pour polyurethane resin into it, the stuff will burn.

[Curt Chiarelli]

As the gentleman said. I believe it's a latex-based product meant for plaster casting and little else. Because it's latex-based the drying time is air-entrained and it takes forever. Also expect a lot of shrinkage and the strong possiblity of warpage.

If I were you I'd purchase a respected brand of silicone rubber and avoid products marketed toward the hobbyist like the plaque. With some noted exceptions, crafts products are not professional grade and, therefore, unreliable in their quality.

[Tommy Allison]

Smooth On makes this absolutely phenomenal brush on silicone. Probably the best product I've ever used. Then there's this poly fiber resin shell mixture that is applied to the outside. It will save you time, and money in materials.

Ask their reps about it.

As far as calling me a Gentleman Curt, you give me far too much credit. :)

[EvilNinjaChris]

yeah I knew there had to be some reason nobody uses it silicone it is...thanks again