Body fillers, commonly known as bondo, are used in automotive body repair to fill dents, scratches, and other imperfections in the vehicle’s bodywork. The procedure begins with preparing the damaged area. First, the area around the dent or scratch is cleaned thoroughly to remove any dirt, grease, or rust. Sandpaper, typically of a coarse grit like 80-grit, is then employed to sand down the area, creating a rough surface for better adhesion of the filler. The sanded area is cleaned again to ensure it is free of debris, dust, or oils that may affect the bonding process. If rust is present, it should be completely removed or treated with a rust converter to prevent future corrosion under the filler.

The next step involves mixing the body filler according to the manufacturer's instructions. The body filler comes in two parts: the filler itself and the hardener. These components are measured in the recommended ratio and mixed thoroughly until achieving a homogeneous color. Once mixed, the filler is applied promptly to the prepared surface before it begins to harden. Using a plastic or metal spreader, the filler is spread over the damaged area, slightly overfilling to allow for sanding. After the filler dries, typically within 20-30 minutes, it is sanded down with progressively finer sandpaper, starting with a medium-grit such as 120-grit and moving to finer grits like 240-grit, to obtain a smooth and level surface. Finally, the filled area is primed and painted to match the surrounding bodywork, ensuring a seamless repair. The result is a restored, smooth finish that is ready for further painting or finishing processes.