Called thermoset polyesters, these materials are glass fiber-reinforced unsaturated polyesters. They are also often referred to as “sheet molding compounds” (SMCs), “fiber-reinforced plastics” (FRPs), or simply “fiberglass.”
Urethane adhesives are the clear market leader in this area. Particularly in the transportation industry, urethanes’ resilience and resistance to peel, fatigue, and impact have made them the first choice for large-area panel bonding, although primers are sometimes needed. Toughened epoxies are also quite useful for bonding fiberglass components; they are used where more load-bearing capability is needed.