painting guide - sunamco · probable causes • improper surface cleaning. ... • ensure that the...

INDUSTRIAL COATINGS MANUFACTURER

Painting Guide Problems, causes and solutions

360 6th Street, Daveluyville, Quebec G0Z 1C0 CanaDa

Toll free: 1 866 815-4080 • Fax: 819 367-4030 • www.sunamco.net • [email protected]

Solvent Popping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Blistering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Runs or Sags. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Cracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Craters/Fish Eyes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Delamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Chipping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Poor Hiding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

no Hold Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Sandscratch Swelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Orange Peel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Wrinkling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Dry Spray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Crawling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Slow Drying . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Water Spotting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18


360 6th Street, Daveluyville, Quebec Canada G0Z 1C0

Toll free: 1 866 815-4080 Fax: 819 367-4030 www.sunamco.com [email protected]

Table of Contents

DescriptionSmall blisters on the paint surface; thosethat have popped appear like craters.

Probable causes• air or solvent vapor trapped in the film, leaving

the film during the drying process, which can leavepop marks.

• Improper surface preparation or cleaning.

• Wrong diluents; probably too fast.

• Excessive film thickness of the undercoat, which may trap solvent.

• Incorrect flash-off time or improper drying timebetween coats.

• Top-coat too heavy.

Solution• If the damage is severe, paint must be removed,

then refinished. In less severe cases, sand untilsmooth and refinish.


Troubleshooting3

Sealer

Primer

Substrate



Prevention• allow surface to be thoroughly cleaned.

• Select the right thinner according to existing

shop conditions:

a) hot condition: use slow thinner

b) cold condition: use fast thinner

• allow sufficient flash-off time and drying

time between each coat.

• apply recommended film thickness.

Solvent Popping

DescriptionHollow bubbles in the paint film.

Probable causes• Excessive moisture in air supplied during

the application.

• Insufficient drying time between coats.

• Improper surface cleaning, tiny specs or dirt left on the surface.

• Temperature too high during application.

• Contamination of compressed air lines.

• Wrong thinner.

• Too heavy coats. It may trap solvents which escapelater and cause blisters.

Solution• Remove the finish and sand through, then refinish.


Troubleshooting4

Sealer

Primer

Substrate



Prevention• Make sure substrate is well cleaned

before painting.

• allow sufficient flash-off time between coats.

• Use proper thinner according to ambientconditions.

• Check humidity in the point shop.

Blistering

DescriptionUsually occurs on vertical surfaces. It’s alocal thickening of the paint film in the formof wavy lines moving downwards.

Probable causes• Film thickness too heavy.

• air pressure too low, causing lack of atomization.

• Substrate’s temperature is too low,

• Wrong amount of thinner (too much).

• Wrong spray techniques.

• Spray gun too close to surface.

• Too much paint.

Solution• Sand smooth and repaint.


Troubleshooting5

Sealer

Primer

Substrate



Prevention• Maintain a suitable, consistent shop temperature

and air flow.

• Install good lighting system in the spray booth.

• Use proper gun adjustment, techniques

and air pressure.

• Select the right finishing tip.

• Use the right thinner according to the

temperature.

• Make sure you follow the technical instructions.

• allow sufficient flash-off time and drying time

between each coat.

Runs or Sags

DescriptionDeep cracks through the paint film where youcan see through the primer or substrate.

Probable causes• Excessive film thickness.

• Coating applied over a previously cracked finish or unstable substrate.

• Substrate too hot or too cold.

• Two components not uniformly mixed.

• Insufficient flash-off time between coats.

Solution• Sand affected area and repaint.


Troubleshooting6

Sealer

Primer

Substrate



Prevention• Remove poor quality product before painting.

• Remove too heavy coats.

• Follow technical recommendations such as:

flash-off time, film thickness, drying time, paint

preparation, etc.

Cracking

DescriptionCraters or fish eyes occur often during the application or immediately after. Paints retract and leave a kind of crater or if it’s smaller and rounder, it’s normallycalled fish eyes.

Probable causes• Improper surface cleaning.

• Surface is contaminated with oil, grease, wax,silicone or other substances.

• Excess of anti-crater.

• Contamination of air supply or air line.

• Hand prints.

• Contaminations from silicone or others.

Solutions• allow the paint to dry.

• Find out the source of the contaminant and remove it.

• Clean substrate thoroughly with soap and water.

• Sand and repaint.

• In certain case, it will be necessary to remove the paint completely and repaint.


Troubleshooting7

Sealer

Primer

Substrate



Prevention• always clean the surface thoroughly.

• Make sure air lines are not contaminated

with oil, moisture or dirt.

• Protect against diesel exhaust fumes or other

airborne contaminants.

• Keep paint shop clean and free

from contaminants.

Craters/Fish Eyes

DescriptionLoss of adhesion between the paint and the substrate. Large pieces of coating are peeling off.

Probable causes• Contamination of the underlying surface

(wax, oil, dirt, grease, etc.)

• Inadequate cleaning or surface preparation.

• Inadequate sanding.

• Too heavy coats.

• Wrong application technique (viscosity, air pressure).

• Surface too hot or too cold when sprayed.

Solution• Remove the detached paint from the affected area,

prepare the underlying surface correctly and repaint.


Troubleshooting8

Sealer

Primer

Substrate



Prevention• Ensure that the surfaces to be painted

are correctly prepared and cleaned.

• Ensure proper sanding along the edges

and areas around hardware.

• Follow technical information (viscosity, air

pressure, reducer etc.).

• Follow recommended film thickness.

• Ensure proper flash-off and drying time

between coats.

Delamination

DescriptionSmall pieces of different shapes losingadhesion from substrate.

Probable causes• Improper surface cleaning.

• Usually caused by an impact.

• Exposed to rough conditions (gravel road).

Solution• Sand then repair area with flexible material.


Troubleshooting9

Sealer

Primer

Substrate



Prevention• Make sure that substrates are well cleaned.

• Make sure that you are using the right material.

• Use recommended system.

Chipping

DescriptionThe paint film doesn’t cover adequately.

Probable causes• Insufficient total film thickness.

• Too much thinner.

• Inadequate lighting in the spray booth.

• Poor spraying techniques.

• Inaccessibility of the surface.

• Poor mixing of the material.

Solutions• Sand the affected area smoothly and repaint.


Troubleshooting10

Sealer

Primer

Substrate



Prevention• Work under good light condition

in the spray booth.

• Follow the recommended dilution.

• Use correct spraying techniques.

• Make sure to apply an even and adequate

film thickness.

• Ensure that material is thoroughly mixed.

Poor Hiding

DescriptionThe primer or sealer is not withstanding the solvent from the topcoat

Probable causes• Primer has been sanded with too coarse grit.

• Primer over sand.

• Substrate not well prepared or cleaned.

• The primer was not dry enough when recoated.

• Top coat applied on an old finish.

Solutions• Sand smooth.

• apply a primer if necessary.

• Repaint.


Troubleshooting11



Prevention• Make sure substrate is well cleaned before

starting the job.

• Use a good coat of primer.

• Follow technical recommendations.


no Hold Out

DescriptionUsually occurs when painting over repairedwork. Sanding scratches in the previouscoat swell through the paint film.

Probable causes• Improper surface preparation and cleaning.


• Wrong sand paper grit (too coarse).

• Excessive primer film build.



Troubleshooting12

Sealer

Primer

Substrate



Prevention• Make sure you have proper surface preparation.

• Use the correct grade of abrasive.

• apply the proper film thickness of the primer.

• allow sufficient flash-off and drying times.

Sandscratch Swelling

DescriptionUneven surface formation, much like the skin of an orange.

Probable causes• Viscosity application too high.

• Too little air pressure causing a lack of atomization.

• Primer applied excessively thick.

• Wrong thinner; too fast.

• Wrong application technique, spray gun too far from the surface.

• Incorrect nozzle adjustment.

• Incorrect ambient or surface temperature, draughts.



Troubleshooting13

Sealer

Primer

Substrate



Prevention• Sand undercoat uniformly.

• adjust viscosity according to the recommendation.

• adjust gun tips and air pressure.

• Use recommended thinner.

• Control ambient temperature of the paint shop.

• allow sufficient drying time between coats.

Orange Peel

DescriptionThe existing paint film shrivels, wrinkles or swells during new finish application or drying.

Probable causesSolvents in newly applied products attack the previousfinish causing wrinkling, raising or puckering of thepaint film:

• Recoating enamels or urethanes that are not fully cured.

• Exceeding maximum times during recoat.

• Wrong solvent.

Solution• Remove lifted areas and refinish.


Troubleshooting14



Prevention• Check solvent sensitivity by rubbing a small

area with thinner or existing finishes

• allow sufficient flash-off times between coats.

• Do not exceed a product’s maximum recoat

time before recoating or after application.

• avoid applying excessively wet undercoats

or topcoats.

Wrinkling

DescriptionGranular texture, normally with no gloss at all.

Probable causes• Improper gun setting, insufficient fluid feed.

• Incorrect viscosity.

• Wrong thinner, too fast.

• Gun pressure too high.

• Wrong application technique; spray gun too far fromsurface while applying – spraying too fast.

Solutions• allow the paint to dry.

• Sand smooth.

• Repaint.


Troubleshooting15



Prevention• Use the recommended thinner according

to the paint shop conditions.

• adjust spray technique; gun setting, spray

pattern, fluid feed, air pressure.

Dry Spray

DescriptionUsually occurs with clear coats. The recedingwet paint film leaves some uncoated areas.Previous coats are visible.

Probable causes• Lack of adhesion when spraying.

• Contamination of the undercoat.

• Undercoat or clear coat might contain silicone.



Troubleshooting16

Sealer

Primer

Substrate



Prevention• Make sure surface to be recoated is free

from silicone contamination.

• Frequently replace tack cloths and rags.

• Pay special attention to problem area.

• Reduce the first coat of the top coat and spray

a mist coat.

Crawling

DescriptionCoating does not cure within the usual time frame.

Probable causes• Incorrect amount of hardener.


• Poor atmosphere conditions during application,coldness, humidity, lack of air movement.

• Wrong reducer.

• Wrong amount of hardener; too much or too little.

• Film too thick.

Solution• Place the parts in warmer and well ventilated area.

The drying process may be accelerated.


Troubleshooting17

Sealer

Primer

Substrate



Prevention• Use appropriate thinner.

• Use a faster thinner when the ambient

temperature is colder.

• apply proper film thickness.


• Improve spraying and drying conditions.

• Increase temperature when too cold.

Slow Drying

DescriptionWhitish spots appearing in the paint film.

Probable causes• Finish was exposed to the rain without being

sufficiently cured.

• Finish washed too soon after application.

• Failure of cross linking due to moisturecontamination.

• Wrong mixing ratio.



Troubleshooting18

Sealer

Primer

Substrate



Prevention• Respect proper curing time before delivering

to the rain.

• Follow technical recommendations.

• Make sure lids are tightly closed immediately

after using hardener.

Water Spotting

painting guide - sunamco · probable causes • improper surface cleaning. ... • ensure that the...

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