How to Repair Rust on the Car's Body
- 1). Wash the vehicle using dish soap and water. Dish soap is gentle enough not to ruin the paint on a vehicle, yet tough enough to cut through dirt, grease and other buildup. It also does not contain the added wax and fillers that traditional car wash liquid has, which leave a film on the vehicle. Wash every area of the car, including the wheel wells and undercarriage.
- 2). Pressure-wash the rusted areas of the vehicle. Pressure washers can be found at self-service car washes if you do not own one. This will get any additional dirt and debris as well as weak metal off the vehicle to prepare it for repair. Once finished, thoroughly dry the vehicle with an absorbent cloth towel to ensure there is no moisture or wash residue left behind.
- 3). Cut around the area that has rust, using tin snips. Measure approximately ¼- to ½-inch from the inside edge of the rust and cut out the entire area. Use a sanding block to remove paint from the end of the cut-out area, no more than ¼-inch inward. Start with the coarse, 36-grit sandpaper and continue with grades up to 1,000-grit. This will give a clean, smooth, workable metal surface that has not been oxidized.
- 4). Measure the cut-out space on the vehicle. Add 1/4-inch to the measurements and cut the thin fiberglass sheet using scissors. It may be necessary to cut several pieces of fiberglass depending on the depth of the metal that is being replaced.
- 5). Attach the fiberglass patch to the outside of the space with fiberglass resin. Let it dry and repeat if multiple layers are necessary. Use the sanding block to sand the fiberglass until it is flush with the automotive metal. Next, start with 36-grit sandpaper and work through the grades, coarsest to finest, to 1,000-grit in order to smooth the surface.
- 6). Wipe away any remaining dust from the surface of the vehicle. Attach plastic sheets with masking tape around the repaired area.
- 7). Spray primer onto the exposed area following the directions on the can. Allow it to dry.
- 8). Choose automobile paint that matches the make and model of your vehicle. Apply it to the repaired area after the primer has dried to complete the finished look.