I've been very happy with Smooth-on's "Smooth Cast" resin. It comes in several formulations for different handling times. These days I use it with their urethane, Vyta-flex, as a Master mold material (and recommend it for it's flexibility and durability). However I've also used Smooth Cast resin quite a bit in the past with various silicone and other synthetic rubber molds without any incident.
John
PS color options? So Strong color tint by the same manufacturer. A little drop with do it (!)
John
PS color options? So Strong color tint by the same manufacturer. A little drop with do it (!)