Freshly sprayed paint may look acceptable from a distance, but up close it's covered with "sesame seed" spots or even shrinks into small craters (fish eyes) — most likely a cleanliness and contamination issue.
I. Particles (Dust Specks)
Dust in the air and clothing fibers fall onto the wet film, and after curing form raised particle spots. The root cause is an unclean spraying environment, insufficient filtration, or inadequate personnel protection.
II. Fish eyes (cratering)
Substrate or compressed air contains oil/water/silicone, causing uneven surface tension of the paint film, and the wet film locally retracts into small holes, namely fish eyes. The more obvious the oil stain points, the larger the shrinkage cavities.
III. Key Control Points
| Problem | Prevention & Control |
|---|---|
| Particles | Keep baking room clean, use three-stage filtration, wear anti-static clothing |
| Fish eyes | Thorough degreasing, oil-water separation of air source, add anti-oil agent |
Summary
Pinholes come from environmental dust settling on the wet film, while fish eyes result from oil and water on the substrate or in the air source causing the paint film to retract and form craters. Prevention relies on a clean spray booth, oil-water separation at the air source, thorough degreasing, and anti-silicone additives; if already occurred, sand and repaint and eliminate the contamination source.
Frequently Asked Questions (FAQ)
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