Hand lay-up techniques

The materials, processes, and techniques, as well as comparisons of various hand and spray-up FRP finished product manufacturing procedures are presented. The steps followed in producing a finished product are noted to nominally comprise coating a form with a gel, build-up of the structure with reinforcing fibers and catalyzed polyester resin, curing, and impaction to remove trapped air. The part emerges with a finished surface prepainted by the gel. Design choices for the percentages and orientation of the reinforcement, the types of fillers, and the types of resins are dictated by the types and intensity of stresses to be encountered by the part in actual use. Examples are provided of the manufacture of a machine cover, a pressure tank formerly made of metal. Techniques for assuring integrity of the laminate in changes of thickness, joints, openings, and severe contours are described.