How to Determine if the Primer is Exposed?
2 Answers
Gently run your finger over the scratch. If you feel noticeable unevenness, it means the primer has been damaged. If you can distinctly feel "a line" when touching it, such a scratch has already reached the primer and requires immediate treatment.
I usually pay close attention to the condition of my car's body, especially after scratches, to check if the primer is exposed. First, observe the color change: a normal paint surface is smooth and glossy, but if the scratch is deep enough to reveal the underlying layer, the color is usually gray, white, or uneven, unlike the consistent surface. Then, gently run your finger over it—if it feels rough or grainy, it might be the primer; if it's still smooth, it's likely just a surface scratch. In good lighting, use a small flashlight or phone light to shine at an angle—you can see the depth of the texture, as the primer reflects light more weakly. Exposed primer is bad news—it can easily rust and stain, damaging the car's structure. I remember last time I scraped the car in a narrow alley, noticed a grayish color, and felt it was like sandpaper. I quickly covered it with wax as a temporary fix and later had it properly repaired at a shop for peace of mind. To prevent this, wax the paint regularly for protection and avoid narrow roads to reduce the risk of scratches. After all, a good-looking car makes driving more enjoyable.
