Bring Back the Shine: An Essential Guide to Rust Repair Using Fiberglass and Bondo

Rust repair using fiberglass is a simple and cost-effective way to address the many forms of rust commonly encountered in automobiles and other vehicles. This method of rust repair is suited for a wide variety of surfaces, including metal, plastic, and wood. Fiberglass provides a corrosion-resistant repair patch that is readily available from most auto body supply stores.

In order to execute a successful fiberglass rust repair, the affected area must be appropriately prepared first. Begin by washing the rust-spotted area of the metal with water and cleaning it with a wax or grease remover. Next, apply metal conditioner with a clean cloth, and use a separate cloth to wipe it off before it dries. This preps the surface of the metal so it is ready for the fiberglass-reinforced filler.

To apply the filler, mix the resin and hardener on a mixing board until it has a uniform color. Use a plastic spreader to spread the appropriately sized amount of patch filler directly onto the rusted area, and allow it to harden. When the filler has cooled, use a sandpaper to block sand the area. If the surface does not level out, apply another thin layer of filler, and then sand again.

Small rust-outs, where rust has eaten away from the backside of the metal, require a slightly different approach to rust repair with fiberglass. Start with the above-mentioned process to prepare the metal, and then apply a rust deactivator to seal out any air or moisture that could lead to further oxidation. Once the rust-outs have been identified, use a pick hammer to bevel the edges of the rust and paint scrapes. Then, apply the waterproof fiberglass reinforced filler to the holes and allow it to harden. Smooth out the surface with a sandpaper until the area is level.

For large rust outs or gaping holes, it may be necessary to use both a cloth patch and a filler to ensure a successful repair. Begin by applying a thin coating of filler onto the rust-affected area and a piece of plastic cut to the size of the rust hole. Place the fiberglass cloth above the plastic piece and then place the patch (fiberglass side down) over the rust hole. Use a plastic spreader to even out the surface and press out any air bubbles. Once the patch is firmly in place, remove the plastic and apply a thin layer of fiberglass-reinforced filler to finish the job. If this area requires painting, be sure to follow instructions for painting fiberglass surfaces.

Rust repair using fiberglass is an efficient and cost-effective way to restore a damaged metal surface. Fiberglass is corrosion-resistant, and its reinforcement capabilities can add needed strength to a weakened structure. Follow these steps to properly apply the patch and filler to ensure a successful and long-lasting repair.