There are many different fiberglass molding processes, including compression molding, blow molding, rotational molding, injection molding and dip molding, among others.
Since its introduction, fiberglass has been used as a reinforcing agent for plastics and as insulation in buildings, homes, stoves, refrigerators, furnaces and in many other applications throughout industry, commerce and in consumer products contexts. Fiberglass moldings are low weight, high strength and scratch resistant. Many boat hulls, go-kart bodies, large storage tanks and automobile parts can be made of molded fiberglass.
Fiberglass molding can be used to make fiberglass sheets, panels, pipes and a wide variety of other shapes. A range of different fiberglass compositions are available to suit the many contexts in which fiberglass moldings are applied. Just a few of these compositions include E-glass, A-glass, E-CR-glass, C-glass and R-glass, each of which features its own properties of strength, durability, UV and corrosion resistance, optical clarity and color.
The three main methods of fiberglass molding are open molding, closed molding, and centrifugal molding. In open molding, a layer of gel coat is applied and cured in a one-piece mold or structure. After being layered into the mold, the fiberglass and sprayed resin are allowed to cure. During closed molding the initial gel coat is applied in a two-part mold.
Fibers in the form of chopped fibers or laminated sheets are sprayed or placed in the female part of the mold on top of the gel coat. The part cures after being sealed in the mold by a vacuum and having catalyzed resin injected into the pressurized mold. In centrifugal molding, the gel coat is applied to the sides of a spinning cylindrical mold.
Layer by layer, catalyzed resins saturated with short fibers are sprayed into the mold until the desired thickness is reached. Centrifugal molding is used to form cylindrical products such as pipes and tanks. In all three processes, the end products are extracted from their molds and subject to any necessary surface treatments or other finishing processes.