420 Aluminum Powder provides limited protection from ultraviolet light in areas that will not be protected with other coatings. Can be used as a base for subsequent painting. 420 will increase the hardness and abrasion resistance of the coated surface and improve its moisture resistance. Cures to a metallic gray color. Add to mixed resin/hardener at the rate of 5 to 10% by volume (approximately 6 oz. per B group).