How to Solve Car Body Rust?
4 Answers
Causes and solutions for rust in multiple areas of the car body: issues with the vehicle's material quality; human factors (failure to address damaged paint over an extended period); and external factors (related to usage environment). Solutions: applying glaze sealing to the car body; conducting regular inspections of the car body, and promptly performing touch-up painting and rust prevention if scratches or rust are found. The specific causes and solutions for rust in multiple areas of the car body are as follows: 1. Automotive Material Application: Due to constraints such as price and brand positioning, vehicles may not use high-quality sheet metal materials, which inherently makes them prone to rust. Solution: Despite material limitations, owners can regularly wax their vehicles or apply rust prevention treatments to the car body. 2. Human Factors: These are mostly caused by improper vehicle use or negligence by the owner, such as leaving damaged paint unrepaired for a long time, exposing the sheet metal surface beneath to air and causing rust; frequently driving through waterlogged areas, leading to prolonged contact between the chassis and water, resulting in rust; not washing the car for extended periods, especially after rain, as rainwater can corrode the car body if not cleaned; frequently parking the car in highly humid areas like beaches or riversides. Solution: Regular maintenance should be performed on the vehicle, and accumulated water or peeling paint should be addressed promptly. 3. External Factors: These are mainly related to the usage environment. Some areas have poor environments with frequent exposure to acid rain or corrosive dust; some regions have humid weather and heavy rainfall, causing severe chassis rust; some places have poor road conditions, leading to frequent chassis impacts or gravel strikes, which damage the surface and increase the likelihood of rust in vulnerable areas like the engine underguard or exhaust pipe. Solution: Whenever possible, park the vehicle in underground garages or indoors; in areas with poor road conditions, consider installing protective armor for the chassis.
My decade-old car also developed rust spots along the door edges before. Actually, small rust spots can be handled DIY. Last time I noticed them, I first sanded off the surface rust with sandpaper to expose the metal layer, then applied anti-rust primer. After the primer dried completely, I carefully touched up the spots with a paint pen matching the original color code, and finally applied a layer of car wax for waterproofing. However, if the rust has eaten through the steel panel, don't push your luck - my friend's car had rusted-through floor pans, and the repair shop had to cut out the rotten sections and weld in new steel plates, costing over 3,000 yuan for a full repaint. Remember to dry water accumulation in crevices after car washes, especially under wheel arches and door sills. Drive through muddy roads on rainy days? Make sure to rinse the undercarriage promptly.
The repair shop mechanic told me there are three types of body rust: surface rust can be resolved with rust remover and sanding; mid-layer rust requires scraping down to bare metal before applying epoxy primer; the most troublesome is rust-through on steel panels, which demands cutting and welding. Last week, I witnessed them working on a car from the seaside—the wheel arches were rusted through like honeycomb charcoal. The metalwork repair alone took an entire day. For areas where de-icing agents are used in northern winters, he suggested applying an anti-rust wax coating to the undercarriage before winter—it really works. A colleague's car gets sprayed annually and shows zero undercarriage rust after eight years.
New car owners should be wary of minor scratches! Last week, I helped my cousin inspect a used car, and the scratches on the inner side of the door handles had all turned into brown rust lines. Such areas can be easily handled by yourself: just buy a metal polishing paste and rub it back and forth, then remember to apply a transparent lacquer the size of a nail polish to seal out the air. Don’t forget to regularly clean the sunroof drainage outlets—my neighbor’s sunroof was clogged for half a year, and rust bubbles appeared on the inner side of the A-pillar before it was noticed. In coastal areas, pay extra attention to cars with aluminum alloy bodies or galvanized steel panels when choosing a vehicle. A friend bought a certain German car with cavity wax injection technology, which indeed prevents rust—after five years, there isn’t even a speck of rust on the chassis.
