Master Bond System EP21S is a two component high strength, tough epoxy resin system for high performance industrial bonding, sealing and coating applications formulated to cure readily at ambient temperatures or more quickly at elevated temperatures with a convenient non-critical mix ratio. A 1/1 mix ratio (weight or volume) produces high tensile strength, tough bonds, sealants or coatings. When a 2/3 mix ratio is employed (weight or volume), toughness is maximized. With a 1/0.5 weight ratio (weight or volume) tensile strength is optimized. All cured EP21S epoxy resin compositions have excellent resistance to thermal cycling and superior resistance to long term exposure to many chemicals including water, acids, bases, oil and most organic solvents, over the exceptionally wide temperature range of -60°F to more than 250°F. Adhesion to metals, glass, ceramics, wood, vulcanized rubbers and many plastics is excellent. The hardened coating is a good electrical insulator. Color of part A clear, part B amber. Master Bond EP21S is widely used in the construction, electrical, computer, electronic, metalworking, appliance, automotive and chemical industries. Impact and abrasion resistance are outstanding. Meets MIL-A-81236 (OS).