BLISTERING

Bubbles that appear in topcoat, often weeks after application. May be small or large
in size. |
Cause:
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Insufficient dry times between coats. |
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Check:
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Application of undercoats too heavy.
Oil, water, or dirt in air lines.
See if blisters are soft. If so, it's either solvent, moisture, or air.
Determine which.
Smell.
Does it crack when thumbnailed?
Check air filtration system. |
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Prevent:
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Always allow sufficient dry times between undercoats, basecoats, clearcoats, etc.
Invest in a good air filtration system.
Drain air lines and compressor tank daily. |
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Correct:
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If blisters are not severe, they may be sanded out, feathered and retopcoated. In
severe cases, finish must be removed and job refinished. |
CHEMICAL STAINING,
WATER SPOTTING or ACID RAIN
Circular discoloration of surface. Dull spots often with outside edges darker than
center. |
Cause:
|
Most common cause is industrial fallout. Chemicals brought to surface of topcoat
by dew or rain. Then chemical reacts with topcoat surface when exposed to sun. |
|
Check:
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Determine if spots or colored stains or "chalky" residue.
Use polishing compound to determine severity.
Is area "eating away" at finish?
Industrial activity in area. |
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Prevent:
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Keep vehicle washed and waxed.
Use basecoat/clearcoat system when possible. |
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Correct:
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Wash surface with detergent and warm water.
Rewash with solution of baking soda and water, flush surface with water and dry.
Rub affected area with polishing compound. If not corrected, refinish. |
CHIPPING
Small areas of a finish that has broken away from undercoat or substrate. |
Cause:
|
Condition is usually caused by mechanical means such as impact of gravel, etc. Condition
occurs more often on an unsealed finish or a finish that does not have two component
undercoats. |
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Check:
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Look at where chipping is occurring, front of vehicle, around wheel wells, etc.
Check for obvious signs of chipping due to road conditions.
Does finish have lacquer primer (sealer or surfacer) underneath?
Is finish coming off of old surface, undercoat?
Determine where adhesion is being lost. |
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Prevent:
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Use two component undercoats.
Use chip guard on areas where chipping is likely to occur. |
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Correct:
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Sand affected area until finish "feathers." Clean and refinish. |
FISHEYES
Small dimples that appear in wet paint finishes. |
Cause:
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Improper cleaning procedures.
Old original finish contains silicone from use of fisheye eliminator during its application.
Oil in air lines.
Excessive amounts or use of fisheye eliminator. |
|
Check:
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How were panels cleaned?
Was surface sanded before cleaning process?
Check for contamination in air lines.
Was fisheye eliminator used? If so, how much and what type? |
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Prevent:
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Always wash areas to be refinished with water and mild detergent.
Clean surfaces before sanding with was and grease remover. Wipe dry before solvent
dries.
Keep air lines clean and drained.
If fisheye eliminator is needed, use only recommended additive in correct amounts. |
|
Correct:
|
If in basecoat (333/337/533), allow base to flash dry 15-30 minutes, sand with 1000
grit and refinish.
On single stage finishes, allow affected coat to flash. Spray additional coats with
appropriate additive. |
METALLIC MOTTLING
Streaked or spotty affect in metallics. This condition occurs when flakes are moved
or pushed together. |
Cause:
|
Spray gun technique inconsistent.
Applying paint too wet.
Spray gun out of adjustment.
Wrong solvent used in material.
Cold shop conditions. |
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Check:
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Check to see if problem is only on horizontal surfaces.
What air pressure was used?
Diaphragm regulator on air source?
What reducer/thinner was used?
Temperature/Metal temperature?
If basecoat, how long did basecoat flash before being clearcoated? |
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Prevent:
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Make correct reducer/thinner/stabilizer selection.
Spray with consistency - air pressure, gun distance, etc.
Spray only above 50F. Also be aware of metal temperature. |
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Correct:
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Allow color to flash off and apply another coat, generally a drier coat. |
ORANGE PEEL
Excessive waviness or unevenness of paint surface. Often a rough look that resembles
an orange skin. Paint droplets drying before flowing together sufficiently. |
Cause:
|
Wrong solvent used to reduce paint.
Improper spray gun technique.
Not enough air pressure.
Spray gun distance too great.
Shop temperature too high. |
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Check:
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Check reducer/thinner, etc.
What air pressure?
Watch painter's spraying technique, if possible.
What fluid nozzle size was used? |
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Prevent:
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Use correct solvent to thin material with respect to temperature and size of job.
Use recommended air pressures and fluid nozzle size. |
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Correct:
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If not too severe, once dry polishing/compounding may help.
If severe, orange peel would need to be sanded smooth and refinished using slower
solvent and correct air pressure. |
PEELING
Finish coming off substrate due to loss of adhesion. (Topcoat from undercoat or old
finish. Undercoat from metal.) |
Cause:
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Lack of preparation/cleaning.
Insufficient undercoat dry times.
Excessive undercoat dry times.
On bare metals, not using etching primers or metal treatments.
Sealers not stirred sufficiently. |
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Check:
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Where is the loss of adhesion?
If between topcoat and sealer, check sealer for settling on bottom of can.
How long did undercoat dry?
Any signs of sanding?
Can you smell solvents when finish is peeled off? |
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Prevent:
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Clean and sand properly. No shortcuts.
Follow undercoat dry times.
Always double check sealers for settling.
Bare metal: use etching primer. |
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Correct:
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Sand affected area until "feathered" and refinished.
In extreme cases, finish may need to be "razorbladed" or stripped and refinished. |