I have recently got into making molds and casting my own custom parts. I ended up using composimolds molding agent. No mixing just microwave and pour...long story short very good stuff.
My problem lies in the plastic. I got some clear 2 part resin which mixes 1:1. The molded plastic takes forever to cure. Like 48 hours and is still very "rubbery". The part that is left over from mixing sets up super fast and hard as a rock. If I were making coasters this shit would be awesome.
Any suggestions on what I am doing wrong or should I use up this crap while honing my skills and go with....(your suggested resin here)