How to repair a completely rusted car door?

[JakeLynn]

Methods to repair a completely rusted car door: First, spray rust remover, then sand it down and repaint. Reasons for car door rust: 1. Poor quality of the steel plate itself leading to rust; 2. Blocked drainage holes causing rust; 3. Damage to the paint surface not being repaired in time leading to rust. The car's paint surface consists of four layers, from inside to out: the electrophoretic layer, the intermediate coat, the color coat, and the clear coat. After the entire car body is assembled, robots immerse the whole body in an electrophoretic tank, forming an electrophoretic layer on the entire body surface, which serves to prevent rust.

[MacRylee]

I've dealt with rusted-through car doors before. First, you need to thoroughly clean the rusted area. Use an angle grinder with a wire brush attachment to remove all rust residue until the bare metal is exposed. For small holes, fill them with fiber filler, while larger holes require welding patches. The key is rust prevention - apply rust-proof primer on the metal surface, let it dry completely, then use body filler to level it, and finally sand it smooth before applying color paint and clear coat. Don't forget to spray rust-proof wax inside the door cavities, otherwise it might corrode from the inside out. After repair, check weekly for bubbles at the repaired spot, especially during rainy seasons. DIY can save you thousands, but lack of experience may leave hidden problems, and the tools take up space. If the rusted area exceeds palm-sized, it's safer to consult a professional auto body technician.

[MatthewLee]

The key to repairing a rusted-through car door lies in rust removal and anti-corrosion measures. Last time, I used rust remover along with sandpaper to grind down to fresh metal, then immediately applied epoxy anti-rust primer—this step is crucial. For temporary repairs, I tried aluminum foil tape, but the results were poor. Later, I learned from repair shops to weld a support mesh with copper wire on the backside before applying anti-rust alloy filler. Make sure to buy genuine color-matched paint to avoid color discrepancies. It's also advisable to replace the door drainage seals to prevent water accumulation and secondary rust. The job takes about two days, with material costs around 200-300 RMB, though professional shops may charge between 500 to 2000 RMB. Avoid using automatic car washes for at least a year after repair, as high-pressure water jets can cause the repaired paint to crack.

[JasmineLee]

Repairing a rusted-through car door involves five steps: After removing rust, cut away the rotted section, use aluminum sheet as backing, and cover with fiberglass resin; fill the surface with body filler, then spray rust-proof primer to seal out air; match the body color paint, using a touch-up pen for small areas with layered application and spray cans for larger areas; finally, cure and apply sealant. The interior is recommended to be treated with rubberized rust-proof coating. Note that original doors have anti-collision beams, which should be avoided during repair. If rust reaches the door frame, it's not worth repairing and the door should be replaced. The repair cycle takes about three days, during which the car should avoid rain. Regular inspection of door seals and drainage holes is crucial, as early detection of small rust spots makes them easier to handle.

[VonAaliyah]

When the lower edge of my old car's left door rusted through, I tried three solutions. First, I directly applied touch-up paint—failed, rust spread from inside; then used metal mesh with AB glue for filling—lasted half a year; finally, a veteran mechanic fixed it properly. He said to thoroughly remove rust with an electric drill, bevel the edges, then weld a patch panel layer by layer. Use alloy-type filler, as regular putty expands when wet. The door cavity must be treated with cavity wax using an injection gun. Nowadays, modern dust-free spray booths yield the best results, with repairs lasting five years. Reminder: always dry door edges after washing, especially in winter when road salt severely corrodes paint.