GPO1

NEMA grade Glass-Mat Reinforced Polyester - GPO-1 (tan color). This grade is composed of random mat (non-woven) fiberglass reinforcement held together by a polyester resin binder. (Polyesters are versatile resins, which handle much like epoxies. Of course, the basic resins are chemically different. It is their physical application forms, which make them similar. Despite lower costs, the important disadvantages of polyesters, as compared with epoxies, is lower adhesion to most substrates, higher polymerization shrinkage, and a greater tendency to crack during cure or in thermal shock and greater change of electrical properties in a humid environment.) GPO-1 offers the least arc resistance.