A toughened, versatile, liquid epoxy for permanent waterproof bonding of fiberglass, ceramics, metals, plastics, and damp and difficult-to-bond woods. With a modulus of elasticity of 150,000 PSI, it is a bit more flexible than standard epoxies and polyester, but much stiffer than adhesive sealants. Makes structural bonds that can absorb the stress of expansion, contraction, shock, and vibration. It is ideal for bonding dissimilar materials. Can be modified with West System fillers and additives and used to wet-out fiberglass tapes and fabrics. Two-part epoxy with a 1-to-1 mix ratio gives you 45 minutes of working time at room temperature. It reaches an initial cure in 7 to 10 hours and full cure in 24 hours.