Small bubbles or pimples ranging in size from 0.5mm - 1.5mm in the topcoat application.
Causes
- High humidity
- Improper surface cleaning
- Incompatibility of materials
- Excessive film builds
- Water, oil, or dirt in air lines
Prevention
- Ensure you are within recommended film build per product data sheet
- Select proper reducer for spray conditions
- Carefully clean substrate
- Do not touch cleaned areas with bare hands
- Drain and clean compressor and regulator to remove trapped contaminants
Correcting
- Establish where the blisters are
- If in between layers, sand blisters. down to a solid surface and refinish
- In severe cases the finish will need to be removed and refinished
