Smooth-Cast™ ONYX™ is a mercury-free urethane resin that cures at room temperature to a deep black, solid plastic. ONYX™ resins offer the convenience of a 1A:1B by volume mix ratio and have very low viscosities, so they are easy to mix and pour. ONYX™ resins have an ultimate Shore hardness of 80D and offer higher physical properties and higher heat resistance vs. other general purpose resins. ONYX™ resins are available in 2 speeds. ONYX™ FAST resin has a pot life of 2.5 minutes and a cure time of 10-15 minutes, while ONYX™ SLOW has a pot life of 5 minutes and a cure time of 90 minutes.

Advantages that ONYX™ resins offer over other resins; 1) if you desire a black casting, adding color pigment is not necessary, 2) cured plastic is ultra-black and darker than competitive black resins, 3) cured ONYX™ plastic can be polished and buffed to a high gloss shine and 4) ONYX™ offers higher heat resistance vs. competitive black resins, 5) unlike other black resins, ONYX™ does not contain mercury and 6) ONYX™ is less expensive vs. other black resins.

Applications include reproducing sculpture, making prototypes and potting / encapsulation. Due to it's quick cure time and hardness, ONYX™ FAST is a good choice for creating fast cold cast bronze, brass, copper, nickel/silver, etc. effects.