Why do you need to paint the whole surface of the car for small scratches?

Why do you need to paint the whole surface of the car for small scratches?

Cars are parked in the open air and run on the road. Small scratches are common. The paint surface of the car is only scratched a little bit. Why should the entire surface be painted? Can you just touch up the paint locally just where it is scratched? Are repair shops and 4S shops deliberately expanding the area of repair painting in order to make more money?

Let's find out why.

1. Prevent the appearance of layer boundaries between new and old paint surfaces If you simply spray paint locally on the scratched position,there will be a more obvious layer boundary between the new and old paint surfaces due to the passage of time. As we all know, old car paint will yellow in the environment of long-term wind, sun and rain, and the yellowing speed will slow down as time goes by. The new paint closely matches the color of the old car paint through complex fine-tuning technology. On the basis of this color, the new paint will also begin to yellow, and the yellowing speed is faster than that of the old car paint. Two kinds of paint surfaces are assembled on the same section, and the difference in yellowing speed can easily lead to the generation of the boundary between the new and old paint surfaces, which is not conducive to the beauty of the car paint.

2. Ensure smoothness The entire paint touch-up process includes sheet metal repair, ash filling, grinding, primer, paint, varnish, baking,polishing, etc. It is obviously impossible to polish onlythe areas that need to be painted very accurately, and choose the whole surface for polishing. , to ensure that the entire surface of the paint is smooth and flat.

3. Reduce chromatic aberration Because the paint surface of the car body is often exposed to the wind and the sun, the color of the car paint will be aging and discolored, and it is difficult to adjust the color of the car paint to be the same as the paint color in the later stage. The interface between the old and new paint is very difficult to handle, and it is easy to cause color difference if you do not do the whole piece.