Does a White Car Showing Black Indicate Exposed Primer?
3 Answers
When a white car reveals black, this black color is the primer. Additional information: 1. The role of automotive primer: Automotive primer is the first layer of coating directly applied to the surface of the treated vehicle component, marking the beginning of the entire coating process. It is designed to have excellent adhesion to the substrate, good compatibility with the intermediate or topcoat layers above, and must also possess superior corrosion resistance, rust prevention, oil resistance, chemical resistance, and water resistance. 2. Requirements for automotive primer: Depending on its application area on the vehicle, automotive primer must exhibit strong adhesion to the substrate, good compatibility with subsequent intermediate or topcoat layers, along with outstanding corrosion resistance, rust prevention, oil resistance, chemical resistance, and water resistance. Naturally, the film formed by automotive primer should also meet mechanical performance standards such as hardness, gloss, flexibility, and stone chip resistance.
I've been driving a white car for three years, and last time I accidentally scraped against a pillar in the parking lot, leaving a scratch on the body that revealed the black underneath. This is definitely the primer showing through. Car paint consists of several layers: the bottom layer is the primer for rust prevention, the middle layer is the white color paint, and the top layer is the clear coat for protection. The primer is usually a dark color like gray or black, serving as an adhesive and anti-corrosion layer. Once exposed, rainwater or dust can enter and corrode the metal body of the car. If left unrepaired for a long time, it could lead to perforation, making repairs more expensive and troublesome. I immediately drove to the shop for a touch-up, and the technician said minor damage could be fixed by local sanding and respraying, costing a few hundred dollars. It's recommended that car owners don't delay in such situations—take photos with your phone for evidence, promptly check if the rust-proof layer is intact, and avoid expanding the problem, which could affect safe driving.
My white car had a similar issue before. The front bumper was hit by a stone, exposing the black paint layer, which was the underlying primer. Primers are mainly gray or black, thicker than the topcoat, and serve to isolate the metal to prevent oxidation. If the exposed primer is left untreated, summer rains can accelerate rusting, and winter salt and snow can corrode the body further, potentially increasing repair costs for rust prevention later. When I notice scratches, I first check their depth: minor scratches might only affect the clear coat, but if it's deep enough to reveal black, the primer is damaged. Solutions include temporarily covering it with a touch-up pen or going to a professional shop for a repaint to restore smoothness. Developing a habit of regular car washing and inspection helps avoid turning small issues into major problems, saving both hassle and money in the long run.
