
Treatment methods for the car's primer coming off are as follows: 1. First, clean the scratched area thoroughly. 2. Prepare a complete touch-up paint kit, soak the sandpaper in water, and wrap it around a hard cotton block. Use the wrapped sandpaper to sand the scratched area until it feels smooth to the touch compared to the surrounding paint. 3. Prepare tape and a cloth to cover areas that do not need touch-up paint; then prepare a touch-up pen and a small spray can, combining them together. 4. At a certain distance from the scratch, start spraying the paint. The sprayed paint can make the car's paint smoother. When spraying, ensure to spray back and forth, avoiding spraying heavily in one spot, until the color covers the blackened area. 5. After the paint is applied, wait a few minutes for it to dry. Then prepare blending clear coat, which can make the touched-up paint color closer to the car's original color and also protect the touched-up paint. Assemble it on the small spray can, maintain a certain distance, and spray back and forth over the touched-up area, avoiding the untouched areas as much as possible. Wait a moment, and the touch-up is complete.

As a car owner who frequently does DIY repairs, if the underbody paint is peeling, here's how to handle it from a DIY perspective: First, assess the size of the affected area. Small patches can be fixed by purchasing a touch-up pen or spray paint kit. Clean the surface thoroughly, removing rust and dust, then lightly sand it smooth before applying primer to prevent rust. After it dries, spray on the matching topcoat—remember to work in a well-ventilated area and avoid over-spraying to prevent drips. Consider whether the car's color is easy to match; take a photo beforehand to show at an auto parts store for reference. DIY saves hundreds, and even the tool cost of 20-30 yuan is worthwhile. After repair, check for other potential issues like stone chips or corrosion signs. Avoid potholes while driving to extend the underbody's lifespan.

From my experience, it's best to drive directly to a professional repair shop if the underbody paint is peeling. Technicians will use specialized equipment to inspect the cause of the peeling, which could be due to stone impacts, aging, or failure of the anti-rust layer. They will first remove rust, apply rust inhibitor to treat the surface, then evenly coat it with factory-matched paint using spray equipment to ensure long-term protection. Professional repairs cost slightly more, ranging from 200-500 RMB depending on the area, but this prevents rust spread that could affect the vehicle's structure. I've seen cases where DIY repairs failed shortly after, requiring more expensive rework. When getting it repaired, ask if they offer a six-month warranty to guarantee free adjustments if needed. Safety comes first - severe underbody rust can affect driving safety, so don't delay treatment too long.

From a maintenance perspective, the loss of underbody paint is often caused by daily wear or corrosion: driving on gravel roads can easily strike the chassis, while rain or salt can erode the paint surface, leading to paint layer peeling over time. If not addressed promptly, metal parts can quickly rust, potentially causing risks such as fuel tank or chassis leaks. I've observed that this is related to vehicle usage habits, with cars frequently driven on highways being more susceptible. Preventive measures include regularly cleaning the chassis after washing the car and applying anti-rust wax to extend protection. Small areas of paint loss can be fixed with DIY touch-up paint, but larger areas require professional inspection to identify the cause and apply the appropriate treatment to avoid more serious issues.


