Paint Cissing and Fish Eyes: Silicone Sources and Surface Decontamination Steps

Fish eyes are circular, crater-like voids that interrupt film continuity, often with a glossy ring around a clear center. Cissing appears as small dimples or pinhole-like impressions where the coating fails to wet correctly. These terms matter because they point to different root causes and corrective steps, not just a generic defect.

On wet films, fish eyes can look like shiny voids that disappear as the film dries, while craters may widen or deepen with time. On cured films, both defects may remain visible but behave differently under light and touch. Distinguish crater morphology from other defects like pinholes or blisters to guide decontamination and recoating decisions.

What fish eyes and cissing mean

Fish eyes and cissing are defects that appear on painted surfaces. They’re caused by localized surface tension failure around a contamination source.

Fish Eyes: These are circular voids or dish-shaped craters, often with a raised edge. Silicone and oils can produce these.

Cissing: This is when the paint forms tiny blisters or wrinkles on the surface. It’s usually due to improper surface preparation or contamination.

Visual differences and common misidentifications

Fish eyes, cissing, orange peel, solvent pop, and dust nibs all look different. Here’s how to tell them apart:

Fish Eyes: Look for circular or crater-like defects with a raised edge.

Cissing: See tiny blisters or wrinkles on the surface.

Orange peel has a textured, orange-peel-like appearance. Solvent pop looks like small bubbles bursting through the paint film. Dust nibs are tiny, hard particles embedded in the paint.

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Typical silicone sources include polishes, release agents, silicone-based sealants, anti-foam additives, certain personal care products, and some tapes or adhesives. Even trace amounts can produce fish eyes or cratering in a freshly applied coating. These sources are often portable and can travel on tools, clothing, or air currents.

To manage this risk, trace sources quickly by interviewing operators, reviewing product usage logs, and performing targeted surface tests in suspected zones. Implement a four-step workflow: identify sources, contain and isolate, decontaminate and test, then verify before coating. Documentation and routine housekeeping help prevent recurrence.

Process and product sources in the shop

The paint shop itself can be a hotbed of silicone contamination. Here are some common culprits:

Body shop cleaners often contain silicones to help degrease and clean surfaces. Detailing compounds, used for polishing and protecting car bodies, also frequently include silicones.

HVAC systems might use silicone-based oils that can leak or be carried by airflow into your paint booth. Materials used during masking and prepping, like certain tapes and adhesives, may also contain silicones.

Personnel and touch-transfer sources

Your team’s personal care products can unintentionally introduce silicone contamination. Here’s how:

Skin lotions, hair products, or even sunscreen can contain silicones that transfer onto parts when touched. This is especially true for gloves and clothing that have been previously used in contaminated areas.

To control this, ensure your team knows not to bring these products into the work area. Provide clean gloves and aprons, and encourage regular hand washing.

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Air currents, HVAC transfer, spray booth plumes, exhaust outlets, and hang-drying zones can carry silicone droplets and oily aerosols long distances. Humidity and temperature influence how far particles travel and where they deposit. Defects can appear remote from the source due to shared air paths.

Look for deposition patterns across panels, especially near intakes or vents, and note inconsistent adhesion near air movement zones. Use smoke tests or flow indicators to map patterns, review maintenance logs, and plan staged cleaning to reduce recontamination risks. Plan isolation or enclosure where practical to minimize spread.

Typical pathways and hotspots

Airborne contaminants don’t just float around aimlessly. They follow specific routes, often concentrating on certain surfaces. Here’s where to look:

Spray booths are prime suspects. Contaminants can cycle through intake and exhaust systems, creating a loop of trouble.

Open doors and windows let in fresh air, but they also invite contaminants from outside or other parts of the workshop.

Drying racks and workbenches are where contaminants love to hang out. Check these hotspots for signs of silicone droplets or oily aerosols.

Monitoring and detection tactics

Catching contamination early is key to preventing widespread issues. Here are some simple monitoring methods:

Set up white test panels. If they show signs of contamination, it’s time for a deeper clean.

Perform solvent wipe tests. Wipe surfaces with a suitable solvent and check for residue. If you find any, you’ve got contamination.

Regular visual checks are crucial. Inspect surfaces for abnormal spots or inconsistent adhesion before painting.

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Establish contamination indicators such as visible residues, silicone transfer, and differences between fish eyes and crater defects. Distinguish silicone issues from water, efflorescence, or other mineral deposits. Document observations to support corrective actions.

In addition to visual checks, perform tactile assessments like drag tests for slickness and test surface tackiness. Note substrate moisture, temperature, and dew point alignment, as these factors affect test validity. Use a standard inspection log with photos and repeatability notes before primer or topcoat.

Solvent Wipe and Tape Adhesion Checks

Before applying primer or topcoat, perform these checks to reveal any oils, silicones, or poor adhesion areas.

Test Spray Panels and Dry-Hold Trials

Before starting high-value work, always test your paint on a small panel or inconspicuous area to confirm no fish eyes appear.

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Follow a fixed sequence: wash, rinse, degrease, dry, decontaminate with approved agents, then a final wipe. Insist on proper order to reduce recontamination and ensure a film-free surface. Verify each step with an inspection before moving forward.

For each step, specify detergents, agitation methods, water quality, and dwell times that maximize contaminant removal without harming the substrate. Always check labels or SDS/technical data sheets for compatibility with primers and coatings before use.