Master Bond Inc.’s EP21FL is a two-part epoxy resin system that features low to moderate viscosity. It is suitable for potting, coating and sealing electronic assemblies and for bonding dissimilar substrates with different coefficients of expansion. Typical viscosity of Part A (clear) is 4000 cycles per second and, of Part B (amber), 10,000 cycles per second, at 25 °C. The system produces strong castings, bonds and seals that are resistant to thermal cycling and shock. Its bond strength is >1500 lb/sq in., and its tensile strength is >1100 lb/sq in. The hardened compound is an electrical insulator and is available in 1/2-pint, pint-, quart-, and 1- and 5-gallon-container kits. It cures at room temperature and, more quickly, at elevated temperatures, with a 4:1 mix ratio by weight. It is 100% reactive and contains no solvents or other volatiles.