Paint troubleshooting

 Dry Spray

Description: A rough, textured surface often confined to a small area.

Cause: Paint lacks ability to flow properly.

Corrective action checklist:

• Check if defect is on whole unit or in specific area.
• Check other units to see if a pattern exists.
• Check if defect is specific to one color or many colors.
• Check for proper film build.
• Check for excessive air pressure.
• Check for improper gun distance.
• Check reducing solvent selection and spray viscosity.

  

Color Match

Description: Finished panels do not match color standard.

Cause: Variations in application and/or paint materials.

Corrective action checklist:

• Check other units on line to determine if a pattern exists.
• Check for complete hiding.
• Check for variables in spray application.
• Check lines and equipment for contamination from previous color.
• Check for improper mixing.
• Check for proper agitation.
• Check gun pattern.
• Check gun distance.
• Check equipment setup.

 

 Dirt

Description: Small bumps deposited in, on, or under the paint film.

Cause: Foreign particles entering wet paint film.

Corrective action checklist:

• Check if defect is on whole unit or in a specific area.
• Check other units to determine if a pattern exists.
• Check paint mixing and filtration process.
• Check spray environment (booth).
• Check preparation process of unit, tacking, solvent wash, etc.
• Check painter's clothing.
• Check spray equipment.
• Check used paint filters for contamination.
• Check for use of anti-static wipe or spray products.

 

Peeling

Description: Topcoat peels off when unmasking.

Cause: Topcoat layer or paint separating because of lack of physical bonding.

Corrective Action Checklist

• Check if defect is on whole unit or in a specific area.
• Check other units to determine if a pattern exists.
• Check film build.
• Check for contamination such as oil, sanding residue, overspray, water, solvent cleaner residue, etc., on substrate prior to topcoat application.
• Check for non-sanding or primer/surfacer.
• Check for case hardening of substrate.
• Check for poor surface preparation prior to topcoat application.
• Check for masking tape contacting painted surface.
• Check solvent selection (too fast).
• Check for thin sealer film builds or no sealer.
• Check for incompatible products.

 

Soft Paint

Description: Easy to mar or penetrate film with fingernail.

Cause: Insufficient cure of paint film.

Corrective action checklist:

• Check if defect is on whole unit or in a specific area.
• Check other units to determine if a pattern exists.
• Check for improper film build.
• Check hardener (old, improper, or contaminated).
• Check for improper mixing ratio.
• Check for improper heat during cure time.
• Check for improper air flow.
• Check flash or dry times.
• Check solvent selection (too fast).
• Check for excessive humidity.

Check for cool temperatures.

 

 Gloss/DOI

Description: DOI is the sharpness by which images are reflected in the surface of a topcoat finish. The images are usually evaluated for 90-degree angle. Gloss measures the amount of light reflected from a paint surface read at 20 and 60-degree angles.

Cause: Poor DOI is caused by an un-smooth or irregular topcoat surface and/or low gloss. Low gloss is caused by improper topcoat application process, or improper solvent selection.

Corrective action checklist:

• Check if defect is on whole unit or in a specific area.
• Check other units to see if a pattern exists.
• Check film build (too low).
• Check solvent selection.
• Check heat during cure process (too low).
• Check air flow during initial cure.
• Check reduction ratio (over reduction).
• Check for uncured undercoats

 

Overspray

Description: Paint materials from another unit falling on adjacent surfaces.

Cause: Misdirected spray droplets or dry spray.

Corrective action checklist:

• Check to determine if defect is on entire unit or in specific area.
• Check other units to see if a pattern exists.
• Check for correct booth air balance and flow.
• Check for sequence of panel application.
• Check gun technique.
• Check if defect is specific to one color.
• Check air pressure (too high).
• Check for over reduction.

 

 Water Blisters

Description: Blisters in paint finish.

Cause:

• Water residue on surface before paint application.
• Water contamination in air supply.

Prevention:

• Thoroughly dry surface before paint application.
• Regular maintenance of air supply.

Repair: Sand flat and respray.

 

 Die Back / Hazing / Loss of Gloss

Description: Loss of gloss in topcoat after application.

Cause:

• Improper evaporation of solvent.
• Poor initial cure.
• Excessive film build of top coat.
• Primer/surfacer wasn't allowed to dry thoroughly.
• Inadequate (short) flash times.

Corrective action checklist:

• Check if defect is on whole unit or in a specific area.
• Check other units to see if a pattern exists.
• Check for solvent selection (too fast).
• Check for cool temperature during cure.
• Check for lack of airflow during cure.
• Check for improper film build.
• Check for improper flash times.
• Check for incompatible products

Prevention:

• Maintain a distance of 8 to 10 inches from surface.
• Choose a suitable hardener/reducer for size of repair and booth temperature.
• Check viscosity using a #2 Zahn viscosity cup.
• Allow proper flash time between coats.
• Use correct gun set up for top coat.

Repair:

• Minor die back, buff to restore gloss.
• Severe die back, sand and respray.

 

 Bull’s Eyes / Edge Mapping / Ring Out / Sand Scratch Swelling

Description: Objectionable sanding pattern imperfections that show through the finished paint film.  Ringing and/ or raised scratches in top coat revealing repairs.

Cause:

• Imperfections due to soft primer.
• Improper sanding techniques and low topcoat film build.
• Excessive film builds with improper flash times.
• Poor feather edging of substrate.
• Body filler or primer/surfacer applied over a reversible substrate.
• Body filler under catalyzed.
• Primer/surfacer not fully cured before recoating.
• Excessive film build used to fill coarse sand scratches.

Corrective action checklist:

• Check if defect is on whole car or in a specific area.
• Check other units to see if a pattern exists.
• Check if defect is specific to one or many colors.
• Check for correct sandpaper grit (too coarse).
• Check topcoat film thickness.
• Check for proper feather edge technique.
• Check for uncured primer.
• Check for poor quality solvent used in undercoats.
• Check flash and dry times.
• Check for excessive primer film builds.
• Check for proper gun technique and atomization.
• Check for under reduced primer surfacer (bridging scratches}.
• Check for sanding before primer surfacer is cured.
• Check film builds of sealer or no sealer.

Prevention:

• Feather edge until surface is smooth and flat.
• Use a water-borne primer on reversible substrates as an isolator.
• Allow sufficient dry time for body filler and or primer/surfacer.
• Use recommended grit of sand paper on substrates.
• Apply recommended product film thickness.

Repair:

• Minor problem - sand and buff.
• Severe problem - allow finish to dry thoroughly, sand flat and respray.

 

Fish Eyes

Description: Craters/pits with raised edges, small rounded indentations that resemble

fish eyes.

Cause:

• Foreign substances that do not blend with paint.
• Surface not thoroughly cleaned with a degreaser.
• Contaminated air supply.

Corrective action checklist:

• Check if defect is on whole unit or in a specific area.
• Check other units to see if a pattern exists.
• Check for oil in air lines and spray equipment.
• Check airborne contamination in spray area.
• Check for possible contamination in paint materials.
• Check for painter contamination, skin oils, perspiration, greasy foods, etc.
• Check for any oils or contamination that might get into paint or spray area.
• Check for proper cleaning procedures prior to refinishing.

Prevention:

• Thoroughly clean surfaces with a degreaser before applying paint products.
• Regular maintenance of air supply.

Repair:

• Minor fish eyes - sand and buff.
• Severe fish eyes - sand flat, thoroughly degrease and respray.

 

Lifting / Wrinkling

Description: Wrinkled or rippled paint surface.

Cause:

• Product applied over a reversible substrate.
• Primer/surfacer wasn't allowed to dry thoroughly before top coating.
• Product applied in critical recoat time (window).

Prevention:

• Apply a water-borne primer as an isolator before coating with other paint products.
• Allow adequate flash or dry time for primer/surface

Repair:

• Minor lifting/wrinkling - sand flat and apply a water-borne primer as an isolator then respray.
• Severe lifting/wrinkling - strip affected panels and reapply paint system.

 

Mottling

Description: Spotty, non-uniform, blotchy appearance of metallic paint.

Cause:

• Uneven distribution of metallic flakes.
• Excessively wet application of color coat.
• Incorrect hardener/reducer for shop temperature.
• Incorrect spray viscosity.

Corrective action checklist:

• Check if defect is on whole unit or in a specific area.
• Check other units to see if a pattern exists.
• Check if defect is specific to one color or many.
• Check for excessively high fluid delivery.
• Check atomizing air pressure.
• Check gun pattern.
• Check gun distance.
• Check equipment set-ups (fluid delivery).
• Check solvent selection.
• Check reduction, viscosity.
• Check flash and dry times.
• Check temperature in spray environment (too cool).
• Check temperature of unit being sprayed.

Prevention:

• Maintain a distance of 8 to 10 inches from surface.
• Choose a suitable hardener/reducer for size of repair and booth temperature.
• Check viscosity using a #2 Zahn viscosity cup.

Repair: Sand and respray

 

Orange Peel

Description: Uneven surface texture resembling the peel of an orange.

Cause:

• Film lacks ability to flow smoothly.
• Rough substrate transmits irregularities to subsequent topcoats.
• Excessive distance between spray gun and vehicle surface.
• Fast hardener/reducer used in high temperatures.
• High spray viscosity.

Corrective action checklist:

• Check if defect is on whole unit or in specific area.
• Check other units to determine if pattern exists.
• Check for low air pressure.
• Check for under reduction.
• Check for proper film build.
• Check for improper gun distance.
• Check reducing solvent and viscosity.
• Check smoothness of substrate.
• Check if defect is specific to one color.
• Check for excessive temperature.

Prevention:

• Maintain a distance of 8 to 10 inches from surface.
• Choose a suitable hardener/reducer for size of repairs and booth temperature.
• Check viscosity using a #2 Zhan viscosity cup.

Repair:

• Minor peel - wet sand and buff.
• Severe peel- sand flat and respray.

 

Pin Holes / Pores

 Description: Pin-prick size holes.

Cause:

• Excessive film build with inadequate flash time before baking.
• Pores in the body filler were not filled.

Prevention:

• Allow proper flash time before baking.
• Apply recommended film thickness.
• Check for and fill pin holes in body filler before painting.

Repair:

• Minor pin holes - sand and respray.
• Severe pin holes - sand thoroughly, fill pin holes with glazing putty and respray.

 

Sags or Runs

Description: Tiers or curtains of paint on vertical or inclined areas.

Cause:

• Paint's inability to uniformly hold to a vertical or inclined surface producing excessive build-up.
• Excessive application of product.
• Incorrect distance between spray gun and surface.
• Slow hardener/reducer used in cold temperatures.
• Low spray viscosity.
• Ambient air temperature below 68 degrees.
• Incorrect (short) flash time between coats.

Corrective action checklist:

• Check if defect is on whole unit or in a specific area.
• Check other units to determine if a pattern exists.
• Check if defect is specific to one color or many colors.
• Check for excessive film build.
• Check for excessive fluid delivery.
• Check for improper gun distance (too close).
• Check solvent selection (too slow).
• Check for insufficient air pressure.
• Check for excessive application overlap.
• Check flash time (too short).
• Check spray room temperature (too low).
• Check temperature of paint.
• Check temperature of unit.
• Check for proper reduction.

Prevention:

• Maintain a distance of 8 to 10 inches from surface.
• Choose a suitable hardener/reducer for size of repair and booth temperature.
• Check viscosity using a #2 Zahn viscosity cup.
• Raise shop/booth temperature.
• Allow proper flash time.

Repair:

• Minor runs/sags - sand and buff.
• Severe runs/sags - sand flat and respray.

 

Solvent Trap (Pop)

Description: A "goose pimple" or volcano appearance in paint film which, on close examination, frequently has small holes in the center of the bumps.

Cause:

• Improper evaporation of solvent from wet paint film during initial cure or force dry.
• Improper application of product: product applied too heavily; inadequate flash time between coats.
• Incorrect mix ratio/viscosity.
• Incorrect hardener/reducer for shop temperature.

Corrective action checklist:

• Check to determine if defect is on entire unit or just in a specific area.
• Check for high temperature in first part of force dry.
• Check other units on line to determine if a pattern exists.
• Check for correct reducing solvent.
• Check if defect is specific to one or many colors.
• Check if defect is most prevalent on horizontal surfaces.
• Check for excessive film builds.
• Check for high fluid delivery.
• Check for low air pressure.
• Check for high viscosity.
• Check for too much overlapping in film build.
• Check for proper flash and purge times.

Prevention:

• Allow adequate flash times.
• Choose a suitable hardener/reducer for size of repair and booth temperature.
• Check viscosity using a #2 Zhan viscosity cup.

Repair:

• Minor pop can be sanded and buffed.
• Severe pop must be thoroughly sanded and repainted.

 

Bleed Through

Description: A light yellow, brown discoloration where the body filler was.

Cause:

• Not use of a stain-free body filler
• Insufficient cure of putty or filler 
• Excessive or insufficient hardener
• Application of coats excessively wet
• Deficient mix

Prevention:

• Apply a stain-free body filler
• Allow proper cure time
• Use the hardener right amount
• Apply medium-wet to wet coats
• Mix components completely

Repair:

• Wait for the topcoat be completely cure
• Sand the area. Isolate with two component undercoats and refinish.