#24/25 is a two-part, equal mix, self-rising, 2lb/ cu. ft. density closed-cell foam system. Foaming begins within 45 seconds after the two liquids are mixed and continues for several more minutes. The foam expands approximately 30 times its liquid volume before curing, and will fill any shape cavity. It does not react with oil or gasoline and it will not absorb water. #24/25 is ideal for floatation applications and provides 60 pounds of floatation per cubic foot of foam. Unlike polyester foams, polyurethane foam is compatible with both polyester and epoxy resins.