How to Deal with Rusty Car Doors?
4 Answers
Methods to handle rusty car doors: 1. If the rust is on the surface and the area is small, you can use water sandpaper to grind off the rust and then spray a layer of anti-rust paint; 2. If the rust has damaged the primer, you need to remove the rust by grinding, spray the primer, and then proceed with topcoat spraying; 3. If the car door is severely rusted with large areas of paint peeling, it is necessary to completely remove the rusted paint, fill and level it with putty, and then spray paint after the putty hardens. Causes of car door rust: After collisions or scratches, the metal body is directly exposed to the outside. Besides common collisions, scratches, and rust from long-term parking, another situation is when small stones kicked up by the tires of the car in front cause small impacts during driving, leading to tiny paint peel-offs and small rust spots. Regularly inspect the car body, engine cover, and around the car, and address any issues immediately once discovered.
I know all too well about door rust issues. Last week while cleaning the door drain holes, I noticed small rust spots near the wheel arches. I bought some rust remover paste to handle it myself: first lightly sand off surface rust with fine sandpaper to expose bare metal, then apply rust converter and wait 15 minutes until it turns black, finally coat with transparent anti-rust wax. This DIY method works great for small rust areas - tools cost just 20 yuan on Taobao. But be warned: if the rust has bubbled up, it means the steel panel is rotting from inside, and you must take it to a repair shop for cutting and welding. Prevention is key - always dry water trapped in door seals after washing, especially for sunroof-equipped cars. Keep a dry towel in the trunk to wipe door sills after rain, it saves lots of trouble.
Never scrape off rust on car doors forcefully! I learned this the hard way—last year, I used a blade to scrape rust off the bottom edge of the door and ended up damaging the original factory coating. Later, a seasoned mechanic taught me the proper procedure: first, apply a metal rust remover and let it soften for three days, then gently scrape with a plastic scraper; once bare metal is exposed, immediately apply epoxy primer to seal it from air; finally, spray matching paint in three thin layers. It's recommended to use a paint thickness gauge—factory paint is around 130 microns, and exceeding this with touch-up paint can lead to cracking. Before the rainy season, spray some WD-40 on door hinges and apply rubber conditioner to seal gaps, preventing moisture ingress. After treatment, inspect for rust spots monthly—if small black dots appear, dab them with nail polish to seal them off.
Door rust is typically handled in three ways: for small rust spots, just use a touch-up paint pen to dab on the area; for coin-sized rust, sand it down to bare metal with sandpaper, apply rust-proof primer, then cover with color paint; for large-scale rust, you must visit a repair shop for panel beating. I always keep a can of undercoating spray on hand—whenever I spot rust near the door drain holes, I spray a layer; the black, rubbery substance fills gaps and prevents rust. Pay special attention to the folded edges along the bottom of the door, as water pools here and rusts through easily. Always wear goggles during treatment—rust dust in the eyes is extremely irritating. For color-matching paint, here’s a trick: don’t just repaint the rusted spot; it’s better to respray the entire door’s rubbing strip for a more natural transition.
