Fibreglass body panels offer the strength of aluminium while significantly decreasing your vehicle's overall weight. You can make fibreglass body panels at home to replace damaged panels after an accident as well as replace existing panels to customise your vehicle. You also can save money making your own fibreglass panels over purchasing panels at retail. To make your own fibreglass panel, you only need a few supplies and a few days' time.
Carefully draw the design and note the dimensions of your existing body panels. If you are customising the panels, you can design it however you like within the limits of your car's dimensions. The most important design aspect is the location of the connection of the panel to the car. This needs to be exactly like the stock panels.
Shape the styrofoam block into a mould for your panel. Use a razor blade or knife to take out the big pieces and 180-grit sandpaper to smooth it out. Cover the styrofoam with an even layer of Bondo and allow it to dry. Once the styrofoam is dry, sand it smooth with 220-grit sandpaper.
Apply the polyester primer over the Bondo in one even coat. Allow the primer to dry before sanding. Drying times will vary according to the manufacturer; follow the directions carefully. Sand the primer with 220-grit sandpaper to start and continue to sand with finer grits. Finish by wet sanding with 1,000-grit sandpaper.
Wax the mould once a day for three days. This will ensure a tight seal and a smooth surface for laying the fibreglass and resin. Cover the mould with three coats of tooling gel, and allow it to get tacky. Once the gel is tacky, brush the resin directly on top of it.
Separate the fibreglass into threads. Make sure there are no large chunks of connected fibreglass. Lay the fibreglass directly on top on the resin, and use a roller to remove air bubbles. Layer the resin and fibreglass six times to ensure a thick body panel. Once dry, pry the panel out of the mould using a wooden mixing stick. Use a razor to remove any protruding pieces of fibreglass.