Many car parts are made of fiberglass, and it is common for fiberglass parts to crack. Taking your vehicle into a body shop to have a simple fiberglass crack repaired can cost a bundle. Fortunately, you can repair cracks in your car’s fiberglass yourself at less cost.
Wash the crack with mild dish soap and water. Rinse and dry completely.
Insert a cone-shaped bit with a tip just slightly wider than the crack into your Dremel. Use the tip of the bit to widen the crack slightly, making sure that the entire crack is exposed. Wipe the area with a damp cloth and dry thoroughly.
Use your plastic spreading tool to completely fill the widened crack with fiberglass epoxy resin. Keep the resin fairly level with the car body, but make certain that the crack is totally filled. Allow the resin to dry for a minimum of 4 hours or per the manufacturer’s directions.
Sand the epoxy smooth with the body of the car using your 240-grit wet paper. Sand until the area feels smooth to the touch.
Sand once again lightly with your 400-grit wet paper until the area feels completely smooth.