About linear cracks in car paint:
The surface of the topcoat has obvious linear crack penetration, and the cracks are relatively parallel, which are most common on black or other dark paint surfaces.
(1) Cause:
①The surface treatment used too coarse sandpaper. The correct way is to use finer sandpaper than the last sanding each time.
② Improper use of thinner and too strong dissolving power, thinner suitable for paint should be used.
③The old paint surface or the previous repaired surface is not fully treated, and the original cracks have traces that have not been removed. This phenomenon often occurs when a new paint layer is sprayed on the original cracked paint layer, so the paint surface is repaired. The repaired area should be thoroughly cleaned.
(2) Correction method:
Use the correct primer and topcoat for old paint and substrates. If cracks appear, smooth the surface with fine-grit sandpaper to expose the inner coat and re-spray with the correct thinner.
