How Long Does It Take for Primer Scratches to Rust?
2 Answers
Primer scratches will typically rust within 3 to 5 months. Methods for repairing primer scratches include: 1. If the scratch is not deep, polishing wax can be used for buffing; 2. Touch-up paint pens can be used, although color mismatch is likely; 3. If the scratch exposes the primer, it is recommended to have it repaired at a 4S shop. Tips for maintaining car primer include: 1. Rinse the car promptly after rain; 2. Wash the car when the engine is cool, avoiding washing under direct sunlight or high temperatures to prevent detergent from drying and leaving marks; 3. Remove dust from the car body promptly after use to minimize static electricity attracting dust.
Last time after the car show, I accidentally scraped my car against a roadside obstacle on the way home, exposing the primer. Within a few days, small rust spots appeared, mainly because it was raining heavily and very humid during that period. The speed of rusting really depends on the situation: if parked outdoors in a humid or salty environment (like near the coast or industrial areas), rust can start to form within 24 hours; in dry and sunny places, it might take one or two weeks before anything happens. From my personal experience, the depth of the scratch matters: shallow scratches may rust more slowly, but deep ones that reach the metal can rust very quickly. My advice is not to wait—immediately dry the affected area and temporarily cover it with car wax or a transparent sticker, which works well for moisture protection. If left untreated, the rust can spread and corrode the car body, even causing structural issues, leading to expensive repairs later. I also asked a mechanic, who said it's best to deal with it within three days—either touch up the paint or simply spray some rust inhibitor, which is both cost-effective and gives peace of mind.
