The glass fibers are dried at 100-110'C for at least 1 hr and then thoroughly mixed into the "Adiprene" L100 in a Hobart mixer, or equivalent. Immediately prior to use, the castor oil is added, and the components are mixed until a uniform blend was obtained. This sealant is designed for use on aluminum substrates. The surface of the aluminum must be cleaned by washing with acetone or methyl ethyl ketone; then apply one brush-coat of Chemlock 607 to the cleaned surfaces and allow to air dry for at least 30 min before applying the sealant. The sealant mixture may be applied with a calking gun or with a trowel. The sealant will cure to a tackfree condition in about 28 hr at 25'C, and will reach full cure in 72 hr at 25'C or in 48 hr at 50'C.