Troubleshooting Guide
Below is a helpful troubleshooting guide for fixing common painting issues!
(Tip: use ctrl+f to quickly pull up certain topics)
Problem Index
- Bleeding
- Blushing
- Color Mismatch
- Dust Contamination
- Edge Mapping
- Fisheyes
- Mottling
- Orange Peel
- Runs/Sags
- Sanding Marks
- Sand scratches
- Shrinkage
- Solvent Popping
- Tape Tracking
- Transparency
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Bleeding
A discoloration in the topcoat color, most often caused by red/red oxide shades
Cause- Solvent in the new topcoat travels down into old finish and dissolves dyes or pigments, allowing them to seep up into the new topcoat and discolor it.
Repair- In order to repair this, you must create a barrier between the original finish and the new finish. One of the best ways to do this by using a gray epoxy primer over the old finish, allowing it to dry before lightly sanding it and refinishing over it.
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Blushing
A milky gray cloud appears on the surface of the paint film immediately or shortly after application
Cause- This is caused by spraying during super humid conditions. Air coming from the spray gun, as well as the solvent evaporating, lowers the paint temperature below the dew point. This causes moisture in the air to condense in or on the paint film. The condition is aggravated when a reducer that dries too fast or an unbalanced reducer is used.
Repair- You have to use a slower-drying reducer, and try to increase the temperature in the room to get more moisture out. Lightly sand where you have some blushing to where it removes the blushed out look, and restart. It is really important to give each coat of paint plenty of flash time so that the solvents and moisture have plenty of time to evaporate, or else they will be trapped inside with nowhere to go. Do not clearcoat over the paint when this happens, because it will show right through the clearcoat as well.
(If possible, try to avoid doing painting and repairs on rainy, foggy, wet days, as this is more and more likely to happen in those conditions.)
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Color Mismatch
The original finish and repair show a noticeable difference in color when viewed in the same lighting.
Cause-
(A) Original finish has “drifted” from manufacturer’s standard
(B) Old finish weathered and oxidized
(C) Color over or under reduced
(D) Improper spray procedures
(E) Color not properly stirred or shaken
(F) Improper spray gun setup
(G) Inaccurate mixing of the color formula
(H) “Panel” painting instead of blending
(I) Evaluating color under a light source other than “color corrected” lighting or natural lighting, or through an electronic screen
(J) Adjusting a color before it has been sprayed, or adjusting a basecoat before applying clearcoat
Repair-
(1) If color is close enough to blend: Prepare adjacent panel(s) for blending, then blend color into adjacent panels. There are plenty of good youtube videos that explain this process.
(2) If color must be tinted: Tint the color for a blendable match, prepare adjacent panel(s) for blending, then respray the repair, blending into the adjacent panel(s).
Prevention-
(A) Check alternate color selector for variances. Choose the alternate that provides a blendable match.
(B) All color must be viewed under equal gloss; compound or polish the area to be matched.
(C) Thin/reduce according to label direction.
(D) Follow label directions for proper application of color coat.
(E) Stir or shake materials thoroughly to be sure all pigments and metallics are in solution.
(F) Refer to product label or data sheet for spray gun, fluid nozzle, and air cap recommendations.
(G) Recheck color code, formula number, formula weights before mixing colors.
(H) Spray a test panel prior to application to determine if blending or tinting is necessary.
(I) Always use natural daylight or color corrected lights to make color matching decisions.
(J) All color must be sprayed out for an accurate evaluation. Basecoats must have clearcoat applied. Check color from all angles, face (90 degrees) and side tone (20-60 degrees)
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Dust Contamination
Foreign particles embedded in paint film
Cause-(A) Inadequate cleaning of the surface to be painted
(B) Dirty spraying equipment
(C) Inadequate air filtration or unfiltered air entering the booth
(D) Dirty or unsuitable work clothes that contain dust, lint, or fibers
(E) Particles from deteriorated air supply lines
(F) Using a poor grade masking paper
(G) Removing the vehicle from the spray booth before the finish is “dust free.”
Repair- Sand with 1200 or finer grit sandpaper, then compound and polish to restore gloss, or sand smooth and refinish
Prevention-
(A) Thoroughly blow off around windows, doors, jambs, hood, trunk, moldings, engine compartment, and wheel openings. Wipe the surface to be painted and the masking paper with a tack cloth.
(B) Maintain a clean working area and spray equipment
(C) Install proper air filters. Never use residential-type furnace filters in the spray booth. Repair any defective air lines, as well as any leakage found in the spray booth due to poor fitting doors, gaskets, seams, or filters.
(D) Wear a lint-free paint suit during the spray operation,
(E) Use quality masking materials. “Wicks” found on newspaper can break away and blow into wet paint.
(F) Vehicle should be kept in a clean environment until the finish is “dust free.” Paint needs to be allowed to fully dry and flash with each coat.
Note- Fine dust particles that fall on a tacky surface can be encapsulated by the finish, creating an appearance almost identical to solvent pop. This “solvent pop” appearance usually occurs on vehicles that are removed from the booth in a tacky condition and placed in another location to dry. Fine dust contamination can be removed by sanding and polishing. However, if the condition is solvent pop the finish will contain pinholes or small craters after sanding.
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Edge Mapping
Rough sand scratches/lifted edges on edge of primer outlining sand-throughs or featheredges
Causes-
(1) Solvent from a new topcoat penetrates a solvent sensitive substrate, causing a lifting or wrinkling that outlines the featheredge.
(2) Sanding through the topcoat to the primer and not going back and priming that area
(3) Neglecting to create a fine etch at the end of your primer edges and leaving it too rough
Repair- Need to let fully dry, then go back over with 800-1000 grit and sand the edges smooth. If needed, add more primer.
OR
(1) Sand smooth or remove the affected area. (final sand with 400 or finer grit sandpaper)
(2) Isolate the affected area with two component primer surfacer and refinish
(3) Or, apply water borne primer surfacer, sand, smooth, and refinish
(4) Or, apply acrylic lacquer primer surfacer thinned with non-penetrating thinner, sand, smooth, and refinish
Prevention- Allow plenty of flash time for each coat. Before priming, make sure you go around all of your edges with 400 grit so that all primer edges will have 400 underneath.
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Fisheye
Small, circular, crater-like openings that appear during or shortly after spraying
Cause-(A) Spraying over surfaces contaminated with oil, wax, silicone, grease, etc. OR using contaminated rags or materials on the surface.
(B) Using lacquer thinner or reducer to clean rather than a solvent cleaner or wax and grease remover actually meant for cleaning
(C) Spraying over previously repaired areas containing “fisheye eliminator” additive.
Repair- To repair, you will have to let the finish to dry and then flatten it out with 800-1000 grit and refinish, as these will rarely buff out. When you are ready to clean it back up before going back over it, clean with wax and grease remover 2-3 times to get all contaminants out.
Prevention- Make sure that you are always using the cleanest, freshest gloves and towels/rags. Thoroughly clean the surface to be painted with detergent and hot water, followed by the recommended solvent cleaner/wax and grease remover. Maintain air supply by draining, cleaning, and changing filter(s) on a routine basis. Avoid applying/using scented products on skin, suits, or clothing, etc.
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Mottling
A streaked, spotty, or striped appearance in a metallic color
(streaking, tiger/zebra stripes, floating, flooding)
Causes-
(A) An uneven distribution of metallic flake caused by:-
Using a spray gun that gives an unbalanced spray pattern
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Improper application technique such as tilting the spray gun during application
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Holding the gun too close to the surface (flooding)
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Uneven spray pattern overlap
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Omitting/improper use of mist coats
(B) Too much thinner/reducer. Color over thinned/reduced
(C) Applying clearcoat to a basecoat that has not thoroughly flashed/dried
(D) Improper application of a basecoat (e.g. failure to apply or an improper use of a low-pressure mist coat, wet basecoat application)
Repair- Allow basecoat color to flash up to 30 minutes, then reapply coats to make more uniform. Be sure your spray patterns are consistent. Finishes that have dried must be sanded and refinished. Caution: Large areas of basecoat must have clearcoat applied before sanding. However, small nibs or lint may be removed from basecoat by wet sanding, concentrating only on the defect. Apply additional basecoat to the sanded area before clearcoating.Prevention-
(A) Use recommended spray gun, including fluid tip and air cap for the material being sprayed. Always adjust the gun for best atomization and balanced spray pattern before paint application.
(B) Use the correct ratio of thinner/reducer.
(C) Allow basecoat proper flash/dry time before clearcoating. Take your time and be patient.
(D) Follow basecoat application procedures.
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Orange Peel
Paint film having an uneven texture that resembles the skin of an orange- bumpy, doesn't show clear reflection off surface
Cause-
(A) Under-reduction and/or air pressure too low
(B) Thinner/reducer evaporates too fast for spray conditions
(C) Excessive film thickness or piling on of heavy, wet coats / not allowing proper flash time
(D) Improper spray gun set-up
(E) Improper painting technique
Repair-
(1) Compound or polish to reduce surface texture
(2) Or, sand smooth with 1200 or finer grit sandpaper, compound, and polish to restore gloss
(3) Or, sand smooth and refinish
Prevention-
(A) Use proper reduction ratio and spray at recommended air pressure.
(B) Select Recommended thinner/reducer based on temperature, humidity, air movement, and size or repair
(C) Avoid heavy coats and excessive film thickness.
(D) Use recommended spray gun, fluid tip, and air cap for the material being sprayed. Always adjust the gun for best atomization and balanced spray pattern before paint application.
(E) During paint application, hold the gun perpendicular and parallel to the surface. Adjust speed of pass, pattern overlap, and distance from the panel to achieve the desired appearance.
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Runs/Sags
Coatings that fail to adhere uniformly, causing beads, droplets, or slippage of the total film
Cause-
(A) Over reduction and/or too slow evaporating thinner/reducer.
(B) Applying paint materials without proper flash time between coats.
(C) Applying excessive wet coats due to:
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Holding the gun too close to the surface
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Slow gun speed
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Double coating
(D) Air pressure too low during spray application
(E) Improper spray gun set-up or an unbalanced spray pattern
(F) Material and/or substrate temperature too cold
Repair-
(1) Remove the wet paint film with solvent, clean, and refinish
(2) Or, after finish is completely dry and cured, remove excess paint by block sanding with 1200 or finer grit sandpaper, compound, and polish to restore gloss
(3) Or, block sand smooth and refinish after paint is dry and cured
Prevention-
(A) Mix according to product directions. Select recommended solvent for spray conditions based on temperature, humidity, air movement, size of repair.
(B) Spray medium wet coats and allow sufficient flash time between coats.
(C) Adjust the spray gun for the best atomization and balanced spray pattern before paint application. Hold the spray gun perpendicular and parallel to the panel. Adjust speed of pass, pattern overlap, and distance from the panel until the desired results are achieved.
(D) Set air pressure at the gun according to product recommendations.
(E) Use recommended spray gun, including fluid tip and air cap combination.
(F) Allow the paint material and substrate to reach room temperature before application.
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Sanding Marks
Dark and/or streaked marks that resemble sand scratches in the paint film
Cause- Scratching or distorting metallic/mica flakes close to the surface of the paint film due to:
(A) Sanding single stage or basecoat metallic finishes prior to clearcoating
(B) Sanding single stage metallic finishes prior to buffing
Repair- Allow finish to dry, sand, and refinish
Prevention-
(A) Avoid sanding basecoat finishes before clearcoating. If sanding is necessary, apply additional color following label directions.
(B) When sanding single stage finishes, confine the sanding to minor imperfections (nib sanding) rather than entire panels. For best results, use 1200 or finer grit sandpaper.
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Sand Scratches
Visible lines or marks in the paint film that follow the direction of the sanding process
Cause-
(A) Sanding the substrate with too coarse grit sandpaper
(B) Insufficient dry/cure of undercoats before sanding and topcoating
(C) Refinishing over soft, soluble substrates (e.g. lacquers, uncured OEM)
(D) Using a poor grade and/or too fast evaporating thinner/reducer for spray conditions causing:
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Primer surfacer to “bridge” over sand scratches
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Topcoat to “skin over,” trapping solvent which swells sensitive substrates.
(E) Using a solvent cleaner that is too strong for the substrate or using thinner/reducer as a surface cleaner after sanding.
Repair-
(1) Allow finish to dry/cure, sand smooth, compound or polish to restore gloss.
(2) Or, sand and refinish after dry/cured.
If you do not allow it to dry, it can lift. The drying is very important.
Prevention-
(A) Sand with recommended grit sandpaper
(B) Allow undercoats to thoroughly dry/cure before sanding and topcoating.
(C) Rub a small area of the old finish with a shop towel saturated with lacquer thinner. If the old finish is soluble or undercured, apply appropriate sealer.
(D) Select recommended thinner/reducer based on temperature, humidity, air movement, and size or repair. Avoid “bridging” existing scratches by applying primer surfacer in thin, wet coats, allowing adequate flash time between each coat.
(E) Use a solvent cleaner designated for either lacquer (soluble) or cured enamel/urethane (insoluble) substrates.
*For best results, use the premium two component undercoat system*
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Shrinkage
The repaired area, featheredge, or sand scratches become visible hours, days, or weeks after the repair is completed
Cause-
(A) Topcoating before undercoats have thoroughly dried/cured
(B) Undercoats applied excessively wet with inadequate flash time between coats
(C) Undercoats under reduced
(D) Using a poor grade and/or too fast evaporating thinner/reducer for spray conditions
(E) Finishing over body filler that has not thoroughly cured
(F) Using too strong solvent cleaner or using thinner/reducer as a surface cleaner
Repair-
(1) Allow the affected area to thoroughly dry/cure, sand and refinish.
(2) If additional filling is necessary, apply a primer surfacer, sand smooth, and refinish after dried/cured.
Prevention-
(A) Allow undercoats to thoroughly dry/cure before sanding and/or top-coating.
(B) Thin or reduce undercoats according to product label directions. Apply in thin, wet coats allowing adequate flash time between coats to avoid “bridging” scratches.
(C) Select recommended thinner/reducer based on temperature, humidity, air movement, and size of repair.
(D) Follow body filler manufacturer’s recommended cure time.
(E) Use solvent cleaner designated for either lacquer soluble or cured enamel/urethane insoluble substrate.
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Solvent Popping
Small bubbles, pinholes, or crater-like openings in or on the paint film
Cause- Liquid solvent (thinners/reducers) becomes “trapped” in the paint film when the surface layer skins over too quickly, preventing their evaporation into the atmosphere. Solvents that vaporize within the paint film leave bubbles, pinholes, or craters as they push through and “pop” the surface. Solvents can be trapped due to:
(1) Thinner/reducer evaporating too fast for spraying conditions
(2) Inadequate flash time between coats
(3) Excessive film thickness or “piling on” of heavy/wet coats
(4) Too much air movement causing surface to “skin over” before solvents evaporate
(5) Excessive purge/flash time before force drying
Repair-
(1) Allow the finish to thoroughly dry/cure, sand smooth, and refinish. Inspect the surface carefully to ensure all craters have been removed.
(2) Severe popping will require removal of the affected film. Prime, seal, and recoat, as necessary.
Prevention-
(A) Select recommended thinner/reducer based on temperature, humidity, air movement, and size of repair.
(B) Allow for proper flash time between coats.
(C) Avoid “piling on” or double wet coats.
(D) Restrict air movement over the surface being painted.
(E) Avoid extended purge/flash time before force drying.
Note- Fine dust particles that fall on a tacky surface can be encapsulated by the finish, creating an appearance almost identical to solvent pop. This “solvent pop” appearance usually occurs on vehicles that are removed from the booth in a tacky condition and placed in another location to dry. Fine dust contamination can be removed by sanding and polishing. However, if the condition is solvent pop the finish will contain pinholes or small craters after sanding.
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Tape Tracking
An imprinted line or texture in the dried paint film following the use of masking tape
Cause-
(A) Finish not dry before taping, causing solvent entrapment between finish and tape
(B) Using a non-automotive tape for multi-color finishes. Solvents from additional color soak through the tape and into the previous color
Repair-
(1) Compound and polish to remove texture
(2) Or, sand with 1500-2000 grit sandpaper, compound, and polish to restore gloss
(3) Or, sand and refinish
Prevention-
(A) Allow the finish to thoroughly dry before masking
(B) Use only high quality automotive masking tape
(C) Determine if it is safe to tape on freshly painted surfaces by applying a small piece of tape to the surface for 10-15 minutes; remove and check for imprinting.
(D) De-tack the tape before applying by pulling the adhesive side of the tape over your pant leg or between your fingers
(E) Remove the tape as quickly as possible after applying additional colors
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Transparency
The original finish or undercoat is visible through the topcoat
Cause-
(A) Color not thoroughly stirred/agitated
(B) Color over thinned/reduced
(C) Substrate not uniform in color
(D) Wrong color undercoat used
(E) Insufficient number of color coats applied
Repair-
(1) Apply additional coats of color until hiding is achieved.
(2) Or, sand and apply similar colored undercoat/ground coat and refinish.
Prevention-
(A) Stir or shake paint material thoroughly, making sure all pigment is in solution.
(B) Thin/reduce according to product label directions.
(C) Use a sealer or ground coat to provide a uniform color before topcoating.
(D) Use an undercoat that is similar in color to the topcoat.
(E) Spray until hiding is achieved.
