Hi Andrew. I have sculpted a pretty nice life size arm in oil based clay, and I want to cast it into something that is durable for my outdoor sculpture garden. What material should I use for the mold, and the sculpture. Plaster won't hold up outdoors, right?...should I use some kind of resin? I don't think that concrete casting stuff could get fine detail. I am assuming you can't take a plaster cast of an oil based clay sculpture, have to use polyurethane? or Silicone? I watched zoe dufours course, but that is water based clay and a plaster waste mold.