Occurrence
Blisters of various sizes, distributions and forms found on the surface of the topcoat. They can occur between the substrate and the coating as well as between coats.
Causes
- Incomplete cleaning of the surface to be painted
- Contamination with salt compounds from dirty water (wet running)
- Dirt that has not been filtered out
- Wet sanding of polyester putty without adequate evaporation time
- Inadequate coating thickness
Prevention
- Thorough washing of components before painting
- Machine sanding (elimination of water absorption by the coating)
- Dry sand polyester products or leave extra time for water to evaporate in wet sanding.
Removal
Remove the coating. Recoat with primer and topcoat.