Unit Size Net Weight Pint Kit 1.8 lb Gallon 18 lb Five Gallon Kit 90 lb Brush-On 50 possesses superior abrasion resistance and tear strength and is ideal for casting concrete and hard plasters in applications where less flexibility is required. Smooth-OnÕs Brush-On Series of mold rubbers are extremely versatile and are famous for their abrasion resistance and high tear strength. They have the convenience of a one-to-one mix ratio and are easy to mix and apply with a brush or spatula. Brush-On 40, 50 & 60 paint onto vertical surfaces without sagging and will cure with negligible shrinkage to durable rubbers that perform and last in production. Each will capture exact detail from any original model.Brush-On 40 is the softest of the series offering the most flexibility and is used for models with deep undercuts. Brush-On 40 can be inverted and used to make glove molds. Brush-On 50 and Brush-On 60 possess superior abrasion resistance and tear strength and are ideal for casting concrete and hard plasters in applications where less flexibility is required. These products are compatible. For example, you can apply two coats of Brush-On 40 and back it up with two coats of Brush-On 50 or 60. All three rubbers are suitable for reproducing sculpture, architectural restoration and production casting of concrete.PropertiesTechnical Properties Mix Ratio by Weight 100A:125B Mix Ratio by Volume 1A:1B Pot Life 20 minutes Cure Time 16 hours Color Off White Shore Hardness 50A Mixed Viscosity Brushable Shrinkage