The first step in the fiberglass mold building process is to create a plug. A plug is the form which is to be duplicated and is usually a representation of the finished part. This can be an actual part, a reproduction, or a completely new form. In planning for the mold, certain factors must be taken into consideration; surface finish, draft angles, undercuts, and method of production. A quality mold surface begins at the plug stage. Every imperfection on the plug surface will be transferred to the mold, and to all subsequent parts. The preferable surface finish for the plug would be a Class "A" finish, which means it would be a polished, high-luster finish, free from any porosity or scratches.
Fibre Glast offers everything you will need to create a durable, high-gloss, Class 'A' finished plug, from polyisocyanurate foam, modeling clay, reinforcement and fairing compound to surfacing primer and mold release products.
Photo Credit: John Gregg, Gregg Drilling & Testing Inc, Signal Hill, CA.