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. This gives G/flex 650 the ability to make structural bonds that can absorb the stress of expansion, contraction, shock, and vibration. It is ideal for bonding dissimilar materials. It can be modified with WEST SYSTEM fillers and additives and used to wet-out fiberglass tapes and fabrics. Mixed at a 1:1 ratio, G/flex 650 gives you 45 minutes of working time at 72°F. It reaches an initial cure in 7 to 10 hrs and full cure in 24 hrs.