The 1600 series are tin (or condensation) cured silicone elastomers and are generally the best for those mold making applications where surface inhibition might be a problem. Easy to use in its ten to one ratio (by weight) these elastomers can be modified by the addition of Viscosil for those situations where one might need a brushable compound, and can also be accelerated by the addition of Rapid Set for those of you who might be in a hurry to make a mold. All of our silicone rubbers can be thinned with Silicone Fluid, and colored with Silicone Pigments. SR-1621 has a Shore A hardness of 23.
