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I'm going to experiment with casting and I want to make reusable molds. I'm looking for recommendations on what RTV silicone product(s) you've found success using. Thanks for any guidance you can offer!

terry curtis

Terry

I suggest you work with a casting resin from Smooth-on. They sell a variety of products designed for plaster mold making, including silicones and urethanes. I have worked with one of their urethanes that has a built in release. It was slick.
http://www.smooth-on.com/

Thicker molds will hold their shape. Thin, paint on coatings require a plaster mother to maintain the right shape. It depends a lot on your original and it's shape.

Hi Terry, one important thing to keep in mind about using silicone rubber is, in general, silicones with higher viscosity
may be more prone to trapping air during mixing [causing bubble problems which shorten mold life] UNLESS you de-gas them under vacuum just after
initial mixing of the rubber.

Lower viscosity [more runny] silicone can often be used without vacuum degassing. You mix the two parts together thoroughly
then pour from a height needed to create a fine stream of rubber which causes trapped air to be released naturally.

There are two type of silicone rubbers, Platinum-cured are more expensive 'cause they don't shrink when curing
and have a longer mold life than Tin-cured.

My experience though is with Polytek's products rather than Smooth-On.

Hope this helps,

Jim