Goggles offer the most protection, but regular safety glasses will suffice. Leather work gloves will give you the most protection from scratches and cuts.
A flapper disc for an angle grinder will also work well for removing the paint. You can purchase a wire brush attachment for your drill at your local auto parts or hardware store. You can also purchase flapper discs for angle grinders at your local hardware store.
A grinder is the faster and preferred method of removing all of the rusted metal, but snips will work in most situations. You can purchase an angle grinder or tin snips from your local hardware store.
Rust inhibitor tends to dry quickly. Wait a minute or two for it to dry before moving on. Follow the instructions on the spray can of rust inhibitor you choose to make sure you apply it correctly. You can get rust inhibitor at any hardware or auto parts store.
Tapping the edged inward will allow you to make a flat, even finish in the fibreglass. Be careful not to dent any of the good metal on the body of the car while you bang in the edges of the hole. Don’t hit any part of the car with the hammer except those edges.
It’s best to do this in direct sunlight or in a well-lit area because you’ll need to be able to see the hole through the wax paper. Use masking tape rather than duct or some other kind of tape because it won’t leave an adhesive residue.
Press the paper against the body of the car with your non-dominant hand as you trace to help you to see the hole better.
Mix the filler and hardener quickly and thoroughly. You only have about 5 minutes to apply the mixture once you make it. The filler and hardener are usually different colours, so it’s easy to tell if they still need to be mixed. Keep mixing the ingredients until the mixture becomes one solid colour.
It doesn’t matter which side of the wax paper you used to trace the hole (shiny or flat side) just as long as you can clearly see its dimensions.
Keep stirring the mixture and adding it to the wax paper so it creates an even patch out of the fibreglass.
Keep adding the mixture until the patch itself is about . 25 inches (0. 64 cm) thick and mostly even. Remember to move quickly because the mixture is already starting to dry.
It doesn’t need to be much. Just add a thin layer of the fibreglass mixture to help your patch stick.
It may help to reposition your hands so one is pinching a top corner and one is pinching a bottom one. Be careful not to let the paper fold so the mixture comes into contact with itself or you’ll have to start over.
Press the patch into the hole firmly. Then use your fingers to make sure it’s attached to the metal all the way around the hole. Use your fingers to flatten and smooth the patch against the area of the car so it follows the contour lines of the vehicle.
The patch will dry faster with good airflow. Open the garage door if you’re working indoors and the weather permits.
The fibreglass patch will stay in place with the wax paper gone. The patch is now secured onto the vehicle.
Be careful not to press too hard into the middle of the patch as you sand or you may break through it. If you accidentally sand too much away, you can mix more fibreglass and add it to the patch, let it dry, and start sanding again.
Let the primer dry overnight before doing any more work to it. At this point, the hole is repaired and won’t start rusting again.
Hold the can about 12 inches (30 cm) away from the area you’re painting and swipe it from left to right as you spray. For larger repairs, you should treat and paint the entire panel of the car if you want it to blend with the rest of the vehicle perfectly. That may be a job for a certified body shop if you don’t have the tools and expertise required.
