What Causes Small Bumps After Car Painting?

[Keith]

If there is water remaining in the spray gun, darker spots will appear on the paint surface. Another possibility is water mist splashing onto the freshly painted surface before it dries. In rare cases, improper putty application may cause bubbles or water spots that cannot be removed, requiring repainting. Below is relevant information about painting: Spray Pattern: An ideal spray pattern should be symmetrical with evenly distributed atomized particles and clear edges. Only a minimal amount of overspray should exist beyond the pattern edges. Lower atomization pressure helps achieve correct, uniform spray patterns while reducing bounce-back and overspray. Spraying Technique: Maintain the spray gun perpendicular to the workpiece surface during application. The distance between the spray gun and the surface typically ranges from 15~30cm, adjusted according to the surface angle. For wetter, darker, and thicker coatings, reduce the distance; for drier, lighter, and thinner coatings, increase the distance.

[LaPresley]

Last time I helped a friend with spray painting, I encountered these tiny dots. At first, I thought it was an issue with the paint, but later realized it was because the surrounding area wasn't cleaned properly, allowing dust and fibers to settle on the paint surface. If the spray gun's pressure isn't adjusted correctly or the distance is too close, it can also cause bumps. The paint material itself is crucial too – if not stirred evenly or mixed in the wrong ratio, particles can form during curing. Primer preparation can't be overlooked either; if sanding isn't thorough or there's residual grease, the paint won't adhere properly. I recommend sanding off this layer of paint and respraying in a dust-free booth. Remember to wipe the car body clean with a tack cloth before painting.

[VonElijah]

After working in the workshop for so many years, I've encountered these small bumps quite often, mostly due to an unclean painting environment. Dust and fibers floating in the air can land on the wet paint surface and form small bumps. The spray gun is also crucial—too much pressure or holding it too close can cause paint buildup. Additionally, insufficient stirring during paint mixing or improper hardener ratios can easily lead to particles. In fact, preparation before painting is especially important: thoroughly degrease and clean the car body, then use masking film to cover the edges. If issues already occur, you'll need to sand from coarse to fine grit and respray the paint surface.

[JohnnyDella]

My car also had these tiny dots after the last touch-up paint job. The repair shop technician said they were caused by dust floating in during the painting process. They told me it could also happen if the paint wasn't stirred evenly, causing small clumps to spray out and form bumps. Poor atomization due to incorrect spray gun distance can also create particles. The solution is actually quite simple - they sanded the bumps smooth with sandpaper and then applied another layer of paint. Now during every maintenance, I make sure to watch them clean the painting environment thoroughly, and they never work when there's too much dust.