Bleeding
Condition : Original finish discolouring
or colour seeping through the new topcoat colour.
Causes
|
Contamination- usually in the form of
soluble dyes or pigments on the older finish before it was repainted.
(This is especially true with older shades of red).
|
Prevention
|
|
Thoroughly
clean areas to be painted before sanding, especially when applying
lighter colours over darker colours.
|
Solution : Apply two medium coats of
Bleeder seal in accordance with label instructions. Then reapply colour
coat.
|
|
Blistering
Condition: Bubbles or pimples appearing
in the topcoat film, often months after application.
Causes
|
|
Improper
surface cleaning or preparation
|
Tiny
specks of dirt left on the surface can act as a sponge and hold moisture.
When the finish is exposed to the sun (or abrupt changes in atmospheric
pressure), moisture expands and builds up pressure. If the pressure is
great enough, blisters form.
|
|
Wrong
thinner or reducer
|
Use of
a fast-dry thinner or reducer, especially when the material is sprayed
too dry or at an excessive pressure. Air or moisture can be trapped in
the film.
|
|
Excessive
film thickness
|
Insufficient
drying time between coats or too heavy application of the undercoats may
trap solvents which escape later and blister the colour coat.
|
|
Contamination
of compressed air lines
|
Oil,
water or dirt in lines.
Prevention
|
|
Thoroughly
clean areas to be painted before sanding. Be sure surface is completely
dry before applying either undercoats or topcoats. Don't touch a
cleaned area as the oils in your hands will contaminate the surface.
|
|
|
Select
the thinner or reducer most suitable for the existing painting
environment conditions.
|
|
|
Allow
proper drying time for undercoats and topcoats. Be sure to let each
coat flash before applying the next.
|
|
|
Drain
and clean air pressure regulator daily to remove trapped moisture and
dirt. Air compressor tank should also be drained daily.
|
Solution : If damage is extensive and
severe, paint must be removed down to undercoat or metal, depending on
the depth of blisters. Then refinish. In less severe cases, blisters may
be sanded out, resurfaced and re-topcoated.
|
|
Blushing
Condition: A milky white haze that
appears on lacquer films.
Causes
|
|
In
hot humid weather, moisture droplets become trapped in the wet paint
film. Air currents from the spray gun and the evaporation of the
thinner tend to make the surface being sprayed lower in temperature
than the surrounding atmosphere. This causes moisture in the air to
condense on the wet paint film.
|
|
|
Excessive
air pressure.
|
|
|
Too
fast a thinner.
|
Prevention
|
|
In
hot humid weather try to schedule painting early in the morning when
temperature and humidity conditions are more suitable, use acrylic
lacquer thinner.
|
|
|
Use
proper gun adjustments and techniques.
|
|
|
Select
the thinner that is suitable for existing painting environment
conditions.
|
Solution : Add retarder to the thinned
colour and apply additional coats.
|
|
Chalking
Condition: Formation on the finish caused
by pigment powder no longer held by the binder, which makes the finish
look dull.
Causes (other than normal
exposure)
|
|
Wrong
thinner or reducer, which can harm topcoat durability.
|
|
|
Materials
not uniformly mixed.
|
|
|
Starved
paint film.
|
|
|
Excessive
mist coats when finishing a metallic colour application.
|
Prevention
|
|
Select
the thinner or reducer that is best suited for existing environmental
conditions.
|
|
|
Stir
all pigmented undercoats and topcoats thoroughly.
|
|
|
Meet
or slightly exceed minimum film thicknesses.
|
|
|
Apply
metallic colour as evenly as possible so that misting is not required.
When mist coats are necessary to even out flake, avoid using straight
reducer.
|
Solution: Remove surface in affected
area by sanding. Then clean and refinish.
|
|
Chemical Staining
Condition: Spotty discolouration of the
surface.
Causes
|
|
Atmospheric
contamination falling on the finish in the presence of moisture or rain
- usually due to adjacent industrial activity.
|
Prevention
|
|
Avoid
contaminated atmosphere or wash surface with detergent and water as
soon as possible after exposure.
|
|
|
Apply
clear coat.
|
Solution: After washing with detergent
and water, rub affected area with rubbing compound and polish. In severe
cases, sand to prime and refinish.
|
|
|
Chipping
Condition: Small chips of a finish losing
adhesion to the underlying layer (substrate) usually caused by impact of
stones or hard objects.
|
|
Cracking
(Line Checking, Micro-Checking)
Condition: A series of deep cracks
resembling mud cracks in a dry pond and in no definite pattern, they are
usually through the colour coat and sometimes the undercoat as well.
Causes
|
|
Excessive
film thickness. (Excessively thick topcoats magnify normal stresses and
strains which can result in cracking even under normal conditions.)
|
|
|
Materials
not uniformly mixed.
|
|
|
Insufficient
flash time.
|
|
|
Incorrect
use of additive.
|
Prevention
|
|
Don't
pile on topcoats. Allow sufficient flash and dry time between coats. Do
not dry by gun fanning.
|
|
|
Stir
all pigmented undercoats and topcoats thoroughly. Strain and where
necessary, add Fish Eye Eliminator to topcoats.
|
|
|
Read
and carefully follow label instructions. (Additives not specifically
designed for a color coat may weaken the final paint film and make it
more sensitive to cracking.)
|
Solution: The affected areas must be
sanded to a smooth finish or in extreme cases removed down to the bare
metal and refinished.
|
|
Crazing
Condition: Fine splits or small cracks
often called 'crowsfeet' that completely checker an area in an irregular
manner.
Causes
|
|
Work
area too cold. (Surface tension of original material is under stress
and literally shatters under the softening action of the solvents being
applied.)
|
Prevention
|
|
Select
the thinner or reducer that is suitable for existing work area
conditions. Schedule painting to avoid temperature and humidity
extremes in the work area or between temperature of work area and your
paint job. (Bring the vehicle to room temperature before refinishing.)
|
Solution: There are two ways to overcome
crazing:
|
|
Continue
to apply wet coats of topcoat to melt the crazing and flow pattern
together (using the wettest possible solvent work area conditions will
allow)
|
|
|
Use a
fast-flashing thinner which will allow a bridging of subsequent
topcoats over the crazing area.
|
|
|
Die Back
Condition: Loss of gloss after
application.
Cause: Improper evaporation of
solvent or poor initial cure.
Suggested
Corrective Action Checklist
|
|
Check
if the imperfection is on the whole unit or in a specific area.
|
|
|
Check
other units to determine if a pattern is beginning to take place.
|
|
|
Check
for too fast a solvent selection.
|
|
|
Check
for cool temperature during cure.
|
|
|
Check
for lack of airflow during cure.
|
|
|
Check
for improper film build up.
|
|
|
Check
for improper flash times.
|
|
|
Check
for incompatible products.
|
|
|
Dirt
Condition: Small bumps deposited in, on,
or under the paint film.
Cause: Foreign particles entering the
wet paint film.
Suggested
Corrective Action Checklist
|
|
Check
if the imperfection is on the whole unit or in a specific area.
|
|
|
Check
other units to determine if a pattern is beginning to take place.
|
|
|
Check
paint mixing/filtration process (was a strainer in place atop the paint
cup when pouring in paint)
|
|
|
Check
the spraying environment (booth, garage, workshop)
|
|
|
Check
preparation process of unit, tacking, solvent wash, etc.
|
|
|
Check
painter's clothing.
|
|
|
Check
the spraying equipment (was it thoroughly cleaned after previous use)
|
|
|
Check
used paint filters for contamination.
|
|
|
Check
for use of anti-static wipe or spray products.
|
|
|
Dry Spray
Condition: A rough, textured surface
often confined to a small area.
Cause: Paint that lacks the ability
to flow properly.
Suggested
Corrective Action Checklist
|
|
Check
if the imperfection is on the whole unit or in a specific area.
|
|
|
Check
other units to determine if a pattern is beginning to take place.
|
|
|
Check
if the defect is specific to one colour or many colours.
|
|
|
Check
for a proper film build up.
|
|
|
Check
for excessive film build up.
|
|
|
Check
the distance of the spray gun from the surface when spraying. (You
should always hold a paint gun at right angles to the surface being
painted from a distance of 6-10 inches.)
|
|
|
Check
reducing solvent selection and spray viscosity.
|
|
|
Featheredge Splitting
Condition: Appears as stretch marks (or
cracking) along the featheredge. Occurs during or shortly after the
topcoat is applied over lacquer primer.
Causes
|
|
'Piling
on' the undercoat in heavy and wet coats. (Solvent is trapped in
undercoat layers which have not had sufficient time to set up.)
|
|
|
Material
not uniformly mixed. (Due to the high pigment content of primer, it's
possible for settling to occur after it has been thinned. Delayed use
of this material without restirring results in applying a film with
loosely held pigment containing voids and crevices throughout, causing
the film to act like a sponge.)
|
|
|
Wrong
thinner.
|
|
|
Improper
surface cleaning or preparation. (When not properly cleaned, primer
coats may crawl or draw away from the edge because of poor wetting and
adhesion.)
|
|
|
Improper
drying. (Fanning with a spray gun after the primer is applied will
result in drying the surface before solvent or air from the lower
layers is released.)
|
|
|
Excessive
use (and film build) of putty.
|
Prevention
|
|
Apply
properly reduced primer in thin to medium coats (150% reduction) with
enough time between coats to allow solvents and air to escape.
|
|
|
Stir
all pigmented undercoats and top coats thoroughly. Select thinner that
is suitable for existing work area conditions.
|
|
|
Select
only thinners that are recommended for existing work area conditions.
|
|
|
Thoroughly
clean areas to be painted before sanding.
|
|
|
Apply
primer in thin to medium coats with enough time between coats to allow
solvents and air to escape.
|
|
|
Lacquer
putty should be limited to filling minor imperfections. Putty applied
too heavily (or too thick) will eventually shrink causing featheredge
splitting.
|
Solution: Remove finish from the
affected areas and refinish.
|
|
Fish Eyes
Condition: Tiny surface finish blemishes
that resemble small circles of popped paint bubbles, which seem to occur
almost as soon as paint hits an auto body surface.
Causes
|
|
Improper
Surface Cleaning Or Preparation
|
Many
waxes and polishes contain silicone, the most common cause of fish eyes.
Small traces of silicone do not allow paint to settle evenly; rather they
cause material to encircle the speck of silicone and form a fish's eye.
Silicone
adheres firmly to the paint film and requires extra effort for its
removal. Even small quantities in sanding dust, rags or from cars being
polished nearby can cause this failure.
- 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 the spray area.
- Check for proper cleaning procedures prior to refinishing.
- Check airborne contamination in spray area.
|
|
Effects
of the old finish or previous repair : Old finish or previous repair may contain
excessive amounts of silicone from additives used during their
application. Usually solvent wiping will not remove embedded silicone.
|
|
|
Contamination
of air lines
: Check for oil in air lines and spray equipment.
|
Prevention
|
|
Precautions
should be taken to remove all traces of silicone by thoroughly cleaning
with wax and grease remover. (The use of Fish Eye Eliminator is in no
way a replacement for good surface preparation).
|
|
|
Add
Fish Eye Eliminator.
|
|
|
Drain
and clean air pressure regulator daily to remove trapped moisture and
dirt. Air compressor tank should also be drained daily.
|
Solution: After affected coat has set
up, apply another double coat of color containing the recommended amount
of Fish Eye Eliminator. In severe cases, affected areas should be sanded
down and refinished.
|
|
Gloss/DOI
Description: DOI is the sharpness by which
images are reflected in the surface of a top coat 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
non-smooth or irregular top coat surface and/or low gloss. Low gloss is
caused by an improper topcoat application process or improper solvent
selection.
Suggested
Corrective Action Checklist
|
|
Check
if the imperfection is on the whole unit or in a specific area.
|
|
|
Check
other units to determine if a pattern is beginning to take place.
|
|
|
Check
film build up (is it too low)
|
|
|
Check
solvent selection.
|
|
|
Check
heat during cure process (too low).
|
|
|
Check
airflow during initial cure.
|
|
|
Check
reduction ratio (over reduction).
|
|
|
Check
for uncured undercoats.
|
|
|
Lifting
Condition: Surface distortion or
shriveling, while the topcoat is being applied or while drying.
Causes
|
|
Use
of incompatible materials. (Solvents in new topcoat attack old surface
which results in a distorted or wrinkled effect.)
|
|
|
Insufficient
flash time. (Lifting will occur when the paint film is an alkyd enamel
and is only partially cured. The solvents from the coat being applied
cause localized swelling or partial dissolving which later distorts the
final surface.)
|
|
|
Improper
dry. (When synthetic enamel type undercoats are not thoroughly dry,
topcoating with lacquer can result in lifting.)
|
|
|
Effect
of old finish or previous repair. (Lacquer applied over a fresh air-dry
enamel finish will cause lifting.)
|
|
|
Improper
surface cleaning or preparation. (Use of an enamel type primer or
sealer over an original lacquer finish which is to be topcoated with a lacquer
will result in lifting due to a sandwich effect.)
|
|
|
Wrong
thinner or reducer. (The use of lacquer thinners in enamel increases
the amount of substrate swelling and distortion which can lead to
lifting, particularly when two toning or recoating.)
|
Prevention
|
|
Avoid
incompatible materials such as a thinner with enamel products or
incompatible sealers and primers.
|
|
|
Don't
pile on topcoats. Allow sufficient flash and dry time. Final topcoat
should be applied when the previous coat is still soluble or after it
has completely dried and is impervious to topcoat solvents.
|
|
|
Select
the thinner or reducer that is correct for the finish applied and
suitable for existing work area conditions.
|
Solution: Remove finish from affected
areas and refinish.
|
|
Line Checking
Condition: Similar to cracking , except that the lines or
cracks are more parallel and range from very short up to about 18 inches.
Causes
|
|
Excessive
film thickness.
|
|
|
Improper
surface preparation. (Often times the application of a new finish over
an old film which had cracked and was not completely removed.)
|
Prevention
|
|
Don't
pile on topcoats. Allow sufficient flash and dry time. Do not dry by
gun fanning.
|
|
|
Thoroughly
clean areas to be painted before sanding. Be sure surface is completely
dry before applying undercoats or topcoats.
|
Solution : Remove color coat down to
primer and apply new colour coat.
|
|
|
Micro-Checking
Condition: Appears as severe dulling of
the film, but when examined with a magnifying glass, it contains many
small cracks that do not touch.
Micro-checking
is the beginning of film breakdown and may be an indication that film
failures such as cracking or crazing will develop.
Solution : Sand off the colour coat to
remove the cracks, then recoat as required.
|
|
Mottling
Condition: Occurs only in metallic’s when
the flakes float together to form a spotty or striped appearance.
Causes
|
|
Wrong
thinner or reducer: Check the reducing solvent and its viscosity.
|
|
|
Materials
not uniformly mixed
|
|
|
Spraying
too wet
|
- Check
solvent selection.
- Check for excessively high fluid delivery.
- Check the equipment setup (fluid delivery).
|
|
Holding
spray gun too close to work: Check the distance of the spray gun from
the surface when spraying. (You should always hold a paint gun at right
angles to the surface being painted from a distance of 6-10 inches).
|
|
|
Uneven
spray pattern: Check your paint spray gun pattern.
|
|
|
Low
Painting Area Temperature
|
- Check
temperature in spray environment (too cool).
- Check temperature of unit being sprayed.
|
|
Alternatives
|
- Check
if the imperfection is on the whole unit or in a specific area.
- Check other units to determine if a pattern is beginning to take place.
- Check for proper flash and dry times.
- Check if defect is specific to one colour or many.
- Check atomizing air pressure.
Prevention
|
|
Select
the thinner or reducer most suitable for existing painting area
conditions.
|
|
|
Stir
all pigmented topcoats - especially metallic’s thoroughly.
|
|
|
Use
proper gun adjustments, techniques and air pressure.
|
|
|
Keep
your spray gun clean (especially the needle fluid tip and air cap) and
in good working condition.
|
Solution: Allow colour coat to set up
and apply a drier double coat or two single coats, depending upon which
topcoat you are applying.
|
|
Orange Peel
Condition: Uneven Surface Formation -
much like the physical appearance of orange peel. Results from poor
coalescence of atomized paint droplets. Paint droplets dry out before
they can flow out and level smoothly together.
Causes
|
|
Improper
Gun Adjustment and Techniques
|
- Check
for low air pressure.
- Check for wide fan spray patterns.
- Check the distance of the spray gun from the surface when spraying. You
should always hold a paint gun at right angles to the surface being painted
from a distance of 6-10 inches. Spraying at excessive gun distances
causes droplets to become too dry during their travel time to the work
surface and they remain as formed by gun nozzle.
- Check the spray gun was setup properly using the correct tips and spray
cap.
|
|
Extreme
Painting Environment Temperature
|
When
the air temperature is too high, droplets lose more solvent and dry out
before they can flow and level properly. The ideal temp to paint at is 20.5
degrees centigrade.
|
|
Improper
Drying
|
Gun
fanning before paint droplets have a chance to flow together will cause
orange peel.
|
|
Improper
flash or re-coat time between coats
|
If the
first coats of enamel are allowed to become too dry, the solvent in the
paint droplets of following coats will be absorbed into the first coat
before proper flow is achieved.
|
|
Wrong
and/or too little thinner or reducer
|
Under-diluted
paint or paint thinner with fast evaporating solvents causes the atomized
droplets to become too dry before reaching the surface.
|
|
Materials
not uniformly mixed
|
Many
finishes are formulated with components that aid coalescence. If these
are not properly mixed, orange peel will result.
|
|
Alternatives
|
- Check
the smoothness of the substrate surface.
- Check if the imperfection is specific to the one colour.
Prevention
|
|
Use
proper gun adjustments, techniques and air pressure.
|
|
|
Schedule
painting to avoid temperature and humidity extremes. Select the thinner
or reducer that is suitable for existing conditions. (The use of a
slower evaporating solvent will overcome this.)
|
|
|
Always
allow sufficient flash and dry times. Never dry by fanning.
|
|
|
Always
allow proper drying time for undercoats and topcoats. (Not too long or
too short.)
|
|
|
Select
the thinner or reducer that is most suitable for existing environmental
conditions to provide good flow and levelling of topcoat.
|
|
|
Reduce
to recommended viscosity with proper thinner/reducer.
|
|
|
Stir
all pigmented undercoats and topcoats thoroughly.
|
Solution: Compounding may help with removing
orange peel from paint - a mild polishing compound for enamel, rubbing
compound for lacquer. In extreme cases, sand down to a smooth surface and
refinish, using a slower evaporating solvent at the correct air pressure.
|
|
Overspray
Condition: Paint materials from another
unit falling on adjacent surfaces.
Cause: Misdirected spray droplets or
dry spray.
Suggested
Corrective Action Checklist
|
|
Check
if the imperfection is on the whole unit or in a specific area.
|
|
|
Check
other units to determine if a pattern is beginning to take place.
|
|
|
Check
for correct booth (work area) air balance and flow.
|
|
|
Check
for sequence of panel application.
|
|
|
Check
paint spray gun technique.
|
|
|
Check
if defect is specific to one colour.
|
|
|
Check
air pressure (too high).
|
|
|
Check
for over reduction.
|
|
|
Paint Colour Matching
Condition: Finished panels that don't
match the colour of standard panels.
Cause: Variations in application
and/or paint materials.
Suggested
Corrective Action Checklist
|
|
Check
other units to determine if a pattern is beginning to take place.
|
|
|
Check
for complete hiding.
|
|
|
Check
for variables in spray application.
|
|
|
Check
lines and equipment for leftover contamination from previous colour.
|
|
|
Check
for improper mixing.
|
|
|
Check
for proper agitation.
|
|
|
Check
gun pattern.
|
|
|
Check
the distance of the spray gun from the surface when spraying. (You
should always hold a paint gun at right angles to the surface being
painted from a distance of 6-10 inches.)
|
|
|
Check
that you setup the equipment correctly.
|
|
|
Paint Runs and Sags
Condition: Heavy application of sprayed
material that fails to adhere uniformly to the surface.
Causes
|
|
Too
much thinner or reducer: Check for excessive fluid delivery.
|
|
|
Wrong
thinner or reducer
|
- Check
the solvent selection is correct (not too slow).
- Check to see if the paint was reduced correctly.
|
|
Excessive
film thickness without allowing proper dry time
|
- Check
for excessive film build up.
- Check for too short flash (dry) time.
- Check for excessive application overlap.
|
|
Low
air pressure (causing lack of atomization), holding gun too close or
making too slow a gun pass
|
- Check
the distance of the spray gun from the surface when spraying. (You should
always hold a paint gun at right angles to the surface being painted from
a distance of 6-10 inches.)
- Check for insufficient air pressure.
|
|
Painting
environment or surface too cold
|
- Check
for low spray area temperature.
- Check temperature of unit.
- Check temperature of paint.
Prevention
|
|
Read
and carefully follow label instructions. Select the thinner or reducer
that is suitable for existing shop conditions.
|
|
|
Select
proper thinner/reducer.
|
|
|
Don't
pile on finishes. Allow sufficient flash and dry time in between coats.
|
|
|
Use
proper gun adjustment, techniques and air pressure.
|
|
|
Allow
vehicle surface to warm up to at least room temperature before
attempting to refinish. Try to maintain an appropriate painting area
temperature for paint areas.
|
Solution : Wash off the affected area
and let dry until you can sand affected area to a smooth surface and
refinish.
|
|
Peeling Paint
Condition: Loss of adhesion between paint
and substrate (topcoat to primer and/or old finish, or primer to metal.)
Causes
|
|
Improper
cleaning or preparation: Failure to remove surface contamination such
as oil, sanding residue, overspray, water, solvent cleaner residue and
other surface contaminants will prevent the finish coat from coming
into proper contact with the substrate.
|
|
|
Poor
surface preparation prior to top coat application
|
- Check
for non-sanding of substrate or primer application.
- Check for case hardening of substrate.
|
|
Materials
not uniformly mixed
|
- Check
for incompatible products.
- Check for a proper film build up.
|
|
Failure
to use proper sealer
|
- Check
solvent selection is correct (not too fast).
- Check for thin sealer film builds or no sealer.
|
|
Alternatives:
Check for masking tape contacting the painted surface.
|
Prevention
|
|
Thoroughly
clean areas to be painted. (It's always good practice to wash the
sanding dust and any surface contamination off the area to be
refinished). Use wax and grease remover prior to applying top coats and
the use of a tack cloth just after using wax and grease remover will
help to pick up very fine particles of lint, dust and other debris.
|
|
|
Use
correct metal conditioner and conversion coating.
|
|
|
Stir
all pigmented undercoats and topcoats thoroughly.
|
|
|
Use
sealers to improve adhesion of topcoats.
|
Solution: Remove finish from an area
slightly larger than the affected area and refinish.
|
|
Pin holing
Condition: Tiny holes or groups of holes
in the finish or in putty or body filler, usually the result of trapped
solvents, air or moisture.
Causes
|
|
Improper
surface cleaning or preparation. (Moisture left on primer will pass
through the wet topcoat to cause pin holing.)
|
|
|
Contamination
of air lines. (Moisture or oil in air lines will enter paint while
being applied and cause pinholes when released during the drying
stage.)
|
|
|
Wrong
gun adjustment or technique. (If adjustments or techniques result in
application which is too wet, or if the gun is held too close to the
surface, pinholes will occur when the air or excessive solvent is
released during dry.)
|
|
|
Wrong
thinner or reducer. (The use of a solvent that is too fast for work
area temperature tends to make the refinisher spray too close to the
surface in order to get adequate flow. When the solvent is too slow,
it's trapped by subsequent topcoats.)
|
|
|
Improper
dry. (Fanning a newly applied finish can drive air into the surface or
cause a skin dry - both of which result in pin holing when solvents
retained in lower layers come to the surface.)
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Prevention
|
|
Thoroughly
clean all areas to be painted. Be sure surface is completely dry before
applying undercoats or topcoats.
|
|
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Drain
and clean air pressure regulator daily to remove to remove trapped
moisture and dirt. Air compressor tank should also be drained daily.
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Use
proper gun adjustments, techniques and air pressure.
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Select
the thinner or reducer that is suitable for existing work area
conditions.
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Allow
sufficient flash and dry time. Do not dry by fanning.
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Solution: Sand affected area down to
smooth finish and refinish.
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|
Sand Scratches
Condition: Objectionable sanding pattern
imperfections that show through the finished paint film.
Cause: Imperfections due to soft
primer, improper sanding techniques and low top coat film build.
Excessive film builds with improper flash times.
Suggested
Corrective Action Checklist
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|
Check
if the imperfection is on the whole unit or in a specific area.
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|
|
Check
other units to determine if a pattern is beginning to take place.
|
|
|
Check
if defect is specific to one or many colours.
|
|
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Check
for correct sandpaper grit (too coarse).
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|
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Check
topcoat film thickness.
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|
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Check
for proper feathered edge technique.
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|
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Check
for uncured primer.
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Check
for poor quality solvent used in undercoats.
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|
|
Check
for proper flash and dry times.
|
|
|
Check
for excessive primer film builds.
|
|
|
Check
for proper paint spray gun technique and atomization.
|
|
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Check
for under reduced primer (bridging scratches).
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|
|
Check
for sanding before primer is cured.
|
|
|
Check
for film builds of sealer or no sealer.
|
|
|
Sand scratch Swelling
Condition: Enlarged sand scratches caused
by swelling action of topcoat solvents.
Causes
|
|
Improper
surface cleaning or preparation. (Use of too coarse sandpaper or
omitting a sealer in panel repairs greatly exaggerates swelling caused
by thinner penetration.)
|
|
|
Improper
thinner or reducer (especially a slow-dry thinner or reducer when
sealer has been omitted.)
|
|
|
Under-reduced
or wrong thinner (too fast) used in primer causes 'bridging' of
scratches.
|
Prevention
|
|
Use
appropriate grits of sanding materials for the topcoats you are using.
|
|
|
Seal
to eliminate sand scratch swelling. Select thinner or reducer suitable
for existing work area conditions.
|
|
|
Use
proper thinner and reducer for primer.
|
Solution: Sand affected area down to
smooth surface and apply appropriate sealer before refinishing.
|
|
Soft Paint
Condition: Easy to damage or penetrate
paint film with fingernail.
Cause: Insufficient cure of paint
film.
Suggested
Corrective Action Checklist
|
|
Check
if the imperfection is on the whole unit or in a specific area.
|
|
|
Check
other units to determine if a pattern is beginning to take place.
|
|
|
Check
for improper film build up.
|
|
|
Check
hardener (old, improper or contaminated).
|
|
|
Check
for improper mixing ratio.
|
|
|
Check
for improper heat during cure (drying) time.
|
|
|
Check
for improper airflow.
|
|
|
Check
flash or dry times.
|
|
|
Check
solvent selection (not too fast).
|
|
|
Check
for excessive humidity.
|
|
|
Check
for cool spray area temperature.
|
|
|
Solvent Popping
Condition: Blisters on the paint surface
caused by trapped solvents in the topcoats or primer - a situation which
is further aggravated by force drying or uneven heating.
Causes
|
|
Improper
surface cleaning or preparation
|
- Check
other units to determine if a pattern is beginning to take place.
- Check if the imperfection is on the whole unit or in a specific area.
- Check if defect is specific to one or many colours.
- Check if defect is most prevalent on horizontal surfaces.
|
|
Wrong
thinner or reducer
|
- Use
of fast-dry thinner or reducer, especially when the material is sprayed
too dry or at excessive pressure, can cause solvent popping by trapping
air in the film.
- Check for correct reducing solvent.
|
|
Excessive
film thickness
|
-
Insufficient drying time between coats and too heavy application of the
undercoats may trap solvents causing popping of the colour coat as they
later escape.
- Check for excessive film build up.
- Check for high fluid delivery.
- Check for high viscosity.
- Check for too much overlapping in film build.
- Check for proper flash and purge times.
|
|
Alternatives
|
- Check
for high temperature in first part of force dry.
- Check for low air pressure.
Prevention
|
|
Thoroughly
clean areas to be painted.
|
|
|
Select
the thinner or reducer most suitable for existing painting area
conditions.
|
|
|
Don't
pile on undercoats or topcoats. Allow sufficient flash and dry time.
Allow proper drying time for undercoats and topcoats. Allow each coat
of primer to flash naturally - do not fan.
|
Solution: For refinishing solvent
popping, if damage is extensive and severe, paint must be removed down to
undercoat or metal, depending on depth of blisters; then refinish. In
less severe cases, sand out, re-surface and re-apply topcoat.
|
|
Water Spotting
Condition: General dulling of gloss in
spots or masses of spots.
Causes
|
|
Water
evaporating on finish before it's thoroughly dry.
|
|
|
Washing
finish in bright sunlight.
|
Prevention
|
|
Do
not apply water to fresh paint job and try to keep newly-finished car
out of rain. Allow sufficient dry time before delivering car to customer.
|
|
|
Wash
car in shade and wipe completely dry.
|
Solution: Compound or polish with
rubbing or polishing compound. In severe cases, sand affected areas and
refinish.
|
|
Wet Spots
Condition: Discoloration and/or the slow
drying of various areas.
Causes
|
|
Improper
cleaning and preparation.
|
|
|
Improper
drying of excessive undercoat film build.
|
|
|
Sanding
with contaminated solvent.
|
Prevention
|
|
Thoroughly
clean all areas to be painted.
|
|
|
Allow
proper drying time for undercoats.
|
|
|
Wet
sand with clean water.
|
Solution: Wash or sand affected areas
thoroughly and refinish.
|
|
Wrinkling
Condition: Surface distortions (or
shrivelling) that occurs while enamel topcoat is being applied (or later
during the drying stage.)
Causes
|
|
Improper
dry. (When a freshly applied topcoat is baked or force dried too soon,
softening of the undercoats can occur. This increases topcoat solvent
penetration and swelling. In addition, baking or force drying causes
surface layers to dry too soon. The combination of these forces causes
wrinkling.)
|
|
|
'Piling
on' heavy or wet coats. (When enamel coats are too thick, the lower wet
coats are not able to release their solvents and set up at the same
rate as the surface layer which results in wrinkling.)
|
|
|
Improper
reducer or incompatible materials. (A fast-dry reducer or the use of a
lacquer thinner in enamel can cause wrinkling.)
|
|
|
Improper
or rapid change in work area temperature. (Drafts of warm air cause
enamel surfaces to set up and shrink before sub-layers have released
their solvents, which results in localized skinning in uneven
patterns.)
|
Prevention
|
|
Allow
proper drying time for undercoats and topcoats.
|
|
|
Don't
pile on topcoats. Allow sufficient flash and dry time.
|
|
|
Select
proper reducer and avoid using incompatible materials such as a reducer
with lacquer products or thinner with enamel products.
|
|
|
Schedule
painting to avoid temperature extremes or rapid changes.
|
Solution: Remove wrinkled enamel and
refinish.
|
|