RTV Silicone Rubber Additives – Thick or Thin

Dimethyl fluid additive: Thins silicone
Cast-a-Mold silicone thinner is a dimethyl fluid with a viscosity of 50 cps. This thinner will be compatible with any of our silicone rubbers. Lowering the viscosity of a
mold making rubber will allow the silicone to flow more easily into smaller detailed areas. We recommend only adding 3% to 5%. Adding too much silicone fluid can adversely effect the physical properties of the silicone itself. Tear and tensile strength will be lowered if too much silicone thinner is used. The thinner can also be used to help replenish the life of a silicone mold. We recommend brushing a small amount into the mold before storage.

Thixotropic Additive : Thickens silicone
Cast-a-Mold thixotropic additive is specifically formulated for brush on molding. After mixing the thixotropic additive 1-3% by weight into the Cast-A-Mold silicone rubber the material will thicken to a creamy paste that can be easily  brushed on vertical or overhead surfaces without sagging or running. A thin layer of non-thixotropic silicone should be applied first to capture detail and achieve a bubble free surface.