PlatSil® FS-20 (Fast-Setting) Silicone Rubber is a two-part, platinum-catalyzed, liquid silicone system that cures (RTV) to a milky white, Shore OO66/A20 rubber. This product offers a simple 1A:1B mix ratio (by weight or volume), a fast demold time of ~25 minutes, and a long pour time (~8 minutes) relative to its cure speed. This allows for fast turn-around of molds and parts with sufficient time to mix and pour. Heat can be used to further accelerate the cure. 
This is a pourable rubber, but it can be easily thickened with PlatThix Liquid Thickener or Fumed Silica for brush-on application.