There a few things that can ruin a nice car like a dented bumper. Luckily, most bumpers are made out of fiberglass instead of metal. This makes them much easier to repair, even if you are not an auto body expert. With the right tools, you can fix small dents and scratches on your car bumper by yourself. Learning this invaluable skill will allow you to make cosmetic and structural repairs to your bumper as soon as they happen.
Get an Inclusive Patch Kit
First, to make the job much easier and save some money on supplies, you should buy an all-inclusive patch kit. These kits are convenient because you don't need to try and find all of the random tools separately. A good kit will include the fiberglass resin, hardener, fiberglass cloth, mixing tray, mixing stick and a small plastic spreader. You should also want a small multi-surface sponge sander with fine grit (100-180). This is all you will need to repair a fiberglass bumper.
Prep the Area
The first step is to prepare the affected area. If there is a physical hole in your bumper, you need to sand the perimeter of the hole. Basically, you want to sand any area where the fiberglass cloth will touch the bumper. You might want to cut the cloth to size and then trace it onto the bumper. Then, just sand the area inside the tracing. Lightly sanding with a sponge will just clean up the surface, but don't sand so hard that you scratch the paint off of the bumper.
Apply the Resin and Cloth
Follow the instructions for mixing hardener with the resin. Once the two elements are mixed, you want to spread them onto the bumper as quickly as possible. For seamless spreading you should tape the cloth onto the bumper. Remove the tape as you spread the resin. Mold the resin so it is flat as possible, but be careful to not scrape away too much. You don't want the texture of the cloth to be noticeable once everything dries.
The fiberglass will need to dry for at least an hour. Then, you can sand to clean up any bumps or edges. You might need to apply a second coat of resin to places where the first coat was too thin.
At this point you bumper will be waterproof and free of any holes. However, there will be a large discolored patch, which you can try to paint yourself or take to an auto body paint shop. If you don't feel comfortable patching your bumper yourself, take your car to an auto body repair shop.