What Causes Paint Bubbling on Cars?
3 Answers
Paint bubbling on cars can be caused by poor paint quality, applying topcoat before the primer is fully dry during repainting, or rust formation on the underlying metal due to moisture. Untreated paint bubbles will affect appearance, gradually expand in size, and eventually lead to paint cracking and peeling, which may damage the car body. The causes of paint bubbling include: 1. Poor paint quality - This issue frequently occurs at roadside repair shops where lower prices often indicate inferior paint materials that may cause problems after application. 2. Applying topcoat over wet primer during repainting - Moisture trapped between the topcoat and body filler can evaporate under high temperatures, creating air pockets that cause paint bubbling. 3. Rust formation on the underlying metal components due to moisture exposure. Treatment method for paint bubbles: The affected area should be scraped off, treated with rust prevention, filled with body filler, allowed to dry completely, sanded smooth, and finally repainted. If paint bubbling occurs due to paint quality or improper repainting, you may file a claim. It's recommended to have the issue assessed by professional technicians at authorized repair shops or 4S stores for proper handling.
I noticed many friends' car paints bubbling up, the root cause is rust starting from inside the steel panels. Just like how inflammation under our skin causes swelling, the car's metal skin gets pushed up by rust. This especially happens in areas like door sills or wheel arches where rainwater accumulates and seeps in, causing hidden rusting. Some cars have poor factory electrocoating with weak spots in the protective layer, leading to bubbling after years in humid environments. Last time when I was washing my car, I found that using a high-pressure washer directly on seal gaps allows water to enter through door drainage holes into the sandwich layers. Never pick at these bubbles with your hands - immediately take it to a professional body shop to grind off all rust and redo anti-corrosion painting, otherwise the rust holes will keep expanding. Try to avoid long-term parking in puddles, and remember to wipe dry any accumulated water around seal edges after washing.
Paint bubbling is 90% caused by rusting metal substrate, just like an apple rotting from the inside out. Moisture trapped in sheet metal layers is the main culprit, especially in seam areas like door sills and lower door edges. I've experienced it myself - a pebble chipped off a rice-grain-sized paint spot that seemed insignificant at the time, but six months later it developed a coin-sized bubble. Now I always keep touch-up paint handy for any exposed metal spots. Pro tip: when washing your car, avoid directing high-pressure water jets straight at door seams - trapped water can't escape and will gradually rust through the steel panel. Address bubbling immediately; last year a neglected case led to complete rust-through of a door's lower edge, requiring a full door panel replacement costing thousands.
