Does anyone know how to make the molds from the plastic sheets?
I am not exactly sure what you mean by making fibreglass moulds from plastic sheets (are the plastic sheets already formed?). If you have actually created the finished product, making a fibreglass copy is easy. In fact, you may even use your existing plastics moulds to create fibreglass components. Plug up the vacum form holes with some plasticine, wax and pva the template and, simply fibreglass over it. This will give you a glass mould that you can use to create new components from.