How to Fix “Fish Eyes” and Paint Defects: Causes and Prevention

Few things are more frustrating during a fresh paint job than watching perfectly atomized paint crater into tiny, ring-like circles across your panel. Known across the collision industry as fish eyes (or silicone craters), this stubborn paint defect exposes bare primer underneath and ruins gloss uniformity.

Fixing fish eyes isn’t just about sanding down the surface—it requires identifying the source of contamination, correcting your air prep workflow, and executing proper surface cleaning protocols.

1. Identifying Root Causes: Where Contamination Starts

Fish eyes occur when liquid paint encounters low-surface-tension contaminants on the substrate or in the air stream. The wet paint literally repels itself away from the foreign substance, creating a crater.

Common Contaminants & Entry Points
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Silicone Dressings:  Tire shines, interior detail sprays, trim polishes
Air Line Pollution:  Compressor pump oil, condensed water droplets
Prep Failures:       Smearing old wax, using dirty shop towels
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The 3 Main Sources of Fish Eyes:

• Silicone Airborne Drift: Silicone is the primary culprit. Wiping tires with shine dressings or spraying interior detailing sprays anywhere near your booth introduces airborne silicone particles that settle onto prepped panels.
• Oil & Moisture in Compressed Air: Leaking compressor piston seals or unfiltered air lines carry oil mist and water droplets straight through the spray gun nozzle into your fresh coat.
• Improper Wax and Grease Removal: Wiping a panel with solvent cleaner using dirty rags or failing to dry the solvent off completely traps residual road tar, tree sap, and carnauba wax inside panel microscopic sand scratches.

2. Air Line Prep: Upgrading Filters and Water Separators

If fish eyes appear consistently across every job regardless of prep, the contaminant is likely traveling inside your compressed air line.

Air Filtration Stage	Target Contaminant	Maintenance Schedule
Stage 1: Water Separator Drop	Bulk liquid condensation & pipe scale	Drain reservoir daily
Stage 2: Coalescing Filter	Oil aerosols down to 0.01 microns	Replace element every 6 months
Stage 3: Desiccant Dryer	Water vapor humidity	Replace beads when color turns pink
Stage 4: Gun Handle Filter	Final trace oils & debris	Replace every 2–3 full spray jobs

Pro Tip: Inspect your compressor tank. If draining the tank produces dark, oily water, your compressor pump seals are wearing out and throwing oil aerosols down the air lines.

3. Panel Preparation: The “Two-Rag Method”

Wiping a panel down with solvent cleaner seems simple, but improper wiping technique actually spreads silicone and wax across the panel instead of removing it.

The Two-Rag Cleaning Technique
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Rag #1 (Soaked with Remover) --> Dissolves surface wax & silicone
Rag #2 (Clean & Bone-Dry)   --> Instantly lifts contaminant away
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How to Execute the Two-Rag Method:

1. Fold Towel #1: Saturate a lint-free microfiber or specialized shop wipe with a dedicated solvent wax and grease remover. Wipe a 2×2 ft section to dissolve surface contaminants.
2. Follow Immediately with Towel #2: Before the solvent evaporates, use a second clean, completely dry towel to wipe the area dry. Towel #1 dissolves the wax; Towel #2 physically removes it from the panel.
3. Never Let Solvent Air-Dry: If solvent wax remover evaporates on the panel before being wiped off with Towel #2, the dissolved silicone settles right back into the sand scratches.
4. Final Tack Rag Wipe: Just before spraying, gently wipe the panel with a sticky tack rag using zero downward hand pressure to remove light dust particles.

4. Recovery Steps: How to Fix a Panel Trapped with Fish Eyes

If fish eyes pop up mid-spray, do not try to drown the craters with heavy wet paint! Adding thick layers of clearcoat over fish eyes traps air bubbles and causes severe solvent pop and paint lifting later.

Fish Eye Recovery Flowchart
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1. Let Panel Cure Completely -> 2. Sand Flat (600/800 grit) 
3. Re-clean (Two-Rag Method)  -> 4. Respray with Fish Eye Eliminator
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Step-by-Step Panel Repair:

1. Allow Full Cure: Let the contaminated basecoat or clearcoat dry and harden completely according to TDS cure times.
2. Sand Panel Flat: Wet sand the panel using 600-grit (for basecoat) or 800-to-1000-grit (for clearcoat) wet sandpaper attached to a firm sanding block. Sand until the raised crater edges and craters are completely leveled flat.
3. Re-Clean Thoroughly: Execute the Two-Rag Method twice to ensure no silicone remnants remain in the freshly sanded grooves.
4. Use Fish Eye Eliminator (If Necessary): On notoriously stubborn panels, add a recommended manufacturer fish eye eliminator additive (smooth flow additive) directly into your mixed paint cup. This lowers the paint’s surface tension, allowing it to flow evenly over micro-contaminants without forming craters.

Prevent Defects Before You Pull the Trigger

Eliminating fish eyes comes down to disciplined shop hygiene: keep silicone products away from paint areas, maintain multi-stage air dryers, and clean every panel using the two-rag wipe method. Taking these steps protects your paint finishes and keeps your booth workflow moving smoothly.