Can Paint Runs on Cars Be Polished?
2 Answers
Paint runs on cars can be polished. For minor runs, after the paint film has completely dried, the affected area can be sanded with 2000-grit sandpaper and then polished, or smoothed with 2000-grit sandpaper before repainting. For larger runs, a blade can be used to shave off a bit, followed by applying two thin coats of body filler or putty with a rubber knife. Then, use an 800-grit water sanding pad with a soft surface to sand until it is mostly smooth before final sanding. Paint Run Phenomenon: Due to uneven paint flow on the coating film, part of the coating may sag downward. Paint runs are a common issue in automotive spray painting. Winter is a high-incidence period for runs because lower ambient temperatures make solvents harder to evaporate, leading to excessive accumulation of paint thinner, slower drying, and thus causing runs. Precautions for Vehicle Painting: During low-temperature spray painting, it is essential to choose the correct hardener and thinner based on the ambient temperature. Properly adjust the spray gun's distance, spray pattern, air pressure, and paint output. Before painting, it is best to test the spray gun on a sample board or spray into the air to adjust the gun to its optimal state.
I've been repairing cars for decades, and paint runs can indeed be fixed by polishing, but it depends on the severity. For minor runs, after the paint has fully dried, use 2000-grit sandpaper with water to gently sand the raised areas until smooth. Then, use a polisher and specialized polishing compound to slowly polish the surface, restoring the shine without damaging the base coat. However, if the run is thick, sanding becomes trickier—you might need to start with coarse sandpaper like 800-grit to avoid grinding through the paint layer. If it's too deep, it's better to repaint for a simpler solution. When polishing, control the speed and pressure to avoid overheating and damaging the paint. Preventing runs is more important—keep the spray gun vertical, apply thin coats multiple times, and avoid spraying too thickly in one go. This way, you can handle it safely and cost-effectively.
