Repair work or modification of a glass-fiber part requires laminators to check thickness, density, and contour of the damaged or defective part to assure a close fit. Each mold must be checked to make certain that all excess moisture has been removed from it. After carefully preparing the surface of the mold with lacquer and wax, lay-up workers mask off areas of the mold which are not to be laminated. Masking materials include cellophane, wax paper, masking tape, or special sprays containing a mold release substance. They select glass- fiber fabric or mats and then cut and shape the material to prevent puckers, pockets, or wrinkles from forming.
Plastic resin is applied to the mold and the fabric is spread onto it.
The cloth is patted or pressed into place by hand or brush. Another layer of plastic resin is applied and the process is repeated until the product has the desired thickness and the plastic has jelled. Before the laminated material has completely set, lay-up workers trim all edges. They cure the material by either letting it set at room temperature, placing it under a heat lamp, or baking in an oven. They check the completed product for conformance with specifications and for defects by measuring with ruler or micrometer, by visual inspection, and by tapping to detect bubbles or dead spots.