ABSTRACT
Open mold, or contact lamination, is the oldest of the methods employed for fabricating fiber reinforced laminates. Cloths give an orthotropic, biaxial reinforcement in the plane of lamination, and their more regular construction allows higher glass contents, hence, the achievement of larger stiffness and strength. For contact molding, epoxies are seldom used other than for short runs of specialized moldings and for moldings requiring specific chemical or elevated temperature resistance. The latter form is more common, but the choice is dictated by which surface of the molding is required to have the prime finish, since only the contact surface of the molding will be fair. Another important consideration is the weight of the mat or cloth used. Clearly, the design properties will require that there be a certain amount of glass fiber in the molding. Higher styrene contents lead to higher exotherms, greater shrinkages, and reduced tensile strengths.
