Can I use a silicone mold to cast polyester resin?
We’ve tried it for 2 different projects and didn’t have much success. The polyester resin doesn’t react well with silicone and won’t cure completely. We ended up having to force it to cure by applying heat. (You can do this by heating up your oven at the lowest setting and putting your mold with resin in it in the oven for 5-10 minutes.) If you find that your gems are still curing tacky, you can also try a resin finishing spray to harden the surface. Thanks to Amethyst Angel for the tip! Oh and try not to set fire to anything if you end up using the oven method! – I found these awesome plastic molds at Michaels used for soaps. Can I use them as molds? Unfortunately no. Those soap molds are for cold-pour soaps and the plastic is very thin. It will melt under high temperatures and since curing resin generates quite a bit of heat… – But you said I could use plastic paint trays! Yes we did. Plastic paint trays tend to be made from much thicker plastic. If it’s made from thinner plastic,
