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.

Back to top ↑

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.

Back to top ↑

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.

Back to top ↑

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.

Back to top ↑

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.

Recommended cleaning products and methods

To effectively clean your surfaces, use the following types of cleaners at appropriate stages:

pH-neutral wash: Use this first to remove dirt and debris. It’s safe for most substrates and won’t leave residue that could affect paint adhesion.

Dedicated silicone removers: Apply these after degreasing to target silicone-based contaminants. Follow the manufacturer’s instructions and safety guidelines, ensuring compatibility with your substrate and coatings.

Solvent wipes/clay bars: Use these for final-stage cleaning or spot treatment of stubborn residues. Ensure they’re compatible with your surfaces and won’t damage them.

Always verify the compatibility of cleaners with your substrates, primers, sealers, and coatings using product labels and SDS/technical data sheets to avoid damaging your surfaces.

Final wipe and preparation immediately before painting

The final-stage cleaning is crucial to minimize recontamination prior to applying primer or topcoat. Follow these steps:

Approved solvent wipe: Use a lint-free cloth dampened with an approved solvent (e.g., xylene, methyl ethyl ketone) to wipe the surface. This removes any remaining contaminants and ensures a clean surface for painting.

Tack-free inspection: After wiping, allow the surface to sit for 10-15 minutes to ensure it’s tack-free. This indicates that no residue or solvent remains on the surface, making it ready for primer application.

Timing is essential in this final stage to prevent recontamination. Perform the final wipe immediately before painting to maintain a clean, film-free surface.

Back to top ↑

Engineering controls include directional airflow, HEPA filtration, and clear shop zoning to separate coating, curing, and cleaning activities. Dedicate tool/material stations to prevent cross-contact and carryover of residues. Workflows should minimize overlap that leads to recontamination.

Administrative controls cover standardized checklists, visible signage, and routine decontamination between tasks. Use sealed, labeled consumables and proper waste handling to cut contamination risk. PPE and training, plus routine inspections, help sustain prevention gains and reduce rework.

Environmental and consumable controls

First, let’s control our environment. Silicone can travel on air currents, so we need to manage airflow.

Use HEPA filtered booths or portable HEPA filters near painting areas. This traps airborne contaminants, including silicone dust from sealants and polishes.

Speaking of sealants and polishes, keep them away from paint areas. They’re silicone-rich and can easily contaminate surfaces.

Now, consumables. Stick to silicone-free tapes, masks, and cleaners. Silicone in these products can transfer onto surfaces and cause issues later.

Personnel procedures and training

Next, let’s set some shop rules for our crew. No lotions or creams in the paint area – silicones can be present in these too.

Mandate clean-room garments. These help prevent touch-transfer contamination.

Change gloves often and wipe hands regularly with a clean, damp cloth. This minimizes silicone transfer from hands onto surfaces.

Training is key. Ensure everyone knows these rules and their importance. Use audit checklists to verify understanding and adherence.

Back to top ↑

Use decision criteria that consider defect type, size, location, substrate, coating system, and service conditions to choose spot repair or full panel recoat. Map defect boundaries and document observations before starting repairs. Isolation and containment are key to preventing spread during repair.

Repair steps include gentle feathered sanding, thorough cleaning, and verifying decontamination with a solvent wipe or industry-standard check. Prime and refinish as directed by the coating system, then inspect for new defects and confirm adhesion. Consult manufacturer guidance when needed and record all relevant data for QA traceability.

Spot Repair Workflow

For small, isolated defects like fish eyes or cissing, spot repairs can save time and material. Here’s how to do it right:

Isolate the defect: Contain the area using painter’s tape to prevent contamination of surrounding surfaces.

Gently sand: Lightly sand the affected area using fine-grit sandpaper (e.g., 220 or 320 grit) to feather edges and promote adhesion. Be careful not to create new defects.

Clean thoroughly: Use recommended cleaning products and methods from your earlier surface decontamination procedure to remove oils, contaminants, and any residue from sanding. Verify complete decontamination with a solvent wipe or ISO cleanliness standard.

When to Strip and Refinish the Complete Area

Sometimes, spot repairs aren’t enough. Here are signs it’s time for a full strip and recoat:

Multiple defects: If fish eyes or cissing cover a large area, attempting spot repairs could lead to an uneven finish.

Widespread contamination: If your initial surface inspection revealed extensive contamination, a full strip and recoat might be necessary to ensure a durable, long-lasting finish.

Failed spot repairs: If previous spot repair attempts have failed or new defects appear after reapplication, it’s time to consult the coating manufacturer and consider stripping the entire area for a fresh start.

Back to top ↑

Start with a pre-job planning checklist that covers materials, tools, surface prep steps, and a small test patch to verify adhesion and decontamination efficacy. Assess environmental factors to tailor ventilation and safety measures. Document responsibilities and schedule early to prevent delays.

Address safety PPE and chemical handling, waste management, and ventilation requirements. Consider cost implications of prevention versus rework, including downtime and material waste. Define a plan for testing surface cleanliness, silicone residue removal, and acceptance criteria before proceeding to coating steps.

Safety, PPE and regulatory notes

Your safety and compliance are paramount during this process. Here’s what you need to know:

Wear appropriate PPE: Gloves, goggles, coveralls, and a respirator or mask are essential when handling solvents.

Safe solvent use: Always follow the manufacturer’s guidelines for safe handling and storage. Never mix different types of solvents together.

Familiarize yourself with local regulations and SDSs (Safety Data Sheets). They provide crucial information on safe usage, potential hazards, and proper disposal procedures.

Cost implications and decision factors

The key cost drivers in this process are materials, labor, downtime, and waste. Here’s how to consider them:

Rework costs: If you don’t decontaminate properly the first time, you’ll face additional labor, material waste, and potential project delays due to rework.

Prevention costs: Investing in proper training, controls, and consumables upfront can prevent these issues, but there’s an initial cost involved.

To estimate economic trade-offs, document the following for your given shop: expected rework rate, surface contamination risk, primer/adhesive compatibility costs, labor rates, material costs, and downtime impacts on project schedules.

Back to top ↑