Shell Shock® FAST and Shell Shock® SLOW are thixotropic plastics that self-thicken when mixed and can be brushed onto vertical surfaces or into rubber molds. Material cures at room temperature with virtually no shrinkage to a hard, durable plastic. Fully cured castings are rigid and can be sanded, primed and painted. Shell Shock® is ideal for making fast, lightweight rigid molds for creating silicone appliances and effects (use as a replacement for gypsum molds). You can also brush a “gel coat” into a rubber mold and back it up with rigid foam, creating a highly detailed lightweight casting.