105 Epoxy Resin is the base material on which all WEST SYSTEM 105 System epoxy compounds are built. It is a clear, pale yellow, low-viscosity liquid epoxy resin. Blended with hardener at the proper ratio, it cures to a hard, solid plastic with superior physical properties. Based on which hardener you choose, it cures at a wide range of temperatures. Once cured, it forms a high-strength solid that is functionally waterproof, and highly resistant to moisture vapor. Gougeon Brothers, Inc. designed 105 Epoxy Resin to wet out and bond with wood fiber, fiberglass, and reinforcing fabrics. It also bonds well with a variety of metals.