Die Cut Viton ® Gaskets. Custom Gasket Mfg. fabricates die cut Viton® rubber gaskets and water jet cut Viton® rubber gaskets in a wide variety of grades, thicknesses and hardness.The standard thickness of Viton ® rubber ranges from 1/64 to 1/4 thick.Viton ® rubbers hardness (durometer) typically spans from 55 to 90 durometer, Shore A. Die cut Viton ® gaskets are generally black or brown in color.Viton ® gaskets are available with or without.ie Cut Viton ® Gaskets. Custom Gasket Mfg. fabricates die cut Viton® rubber gaskets and water jet cut Viton® rubber gaskets in a wide variety of grades, thicknesses and hardness.