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Advice - 43 Problem Solving Paint Tips

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Bubbling in the container

Causes

Product overly shaken.

Low quality product.

Solutions

Let the product rest: bubbles will disappear after a while. This settling period may vary from one product to another. To make the bubbles disappear more rapidly, slowly stir the product, moving the stirring spatula up and down.

Use a higher quality product.


Bulged container

Causes

Overly high temperatures or significant temperature variations during storage.

Pressure triggered by the coating inside the container reacting to water or humidity.

Solutions

Check the room temperature. The product should not be exposed to extreme heat.

Carefully open the container to release pressure.


Knot bleeding

Causes

This problem usually affects woods with knots containing resin (pine, spruce and fir). Solvents in coatings dissolve resin. During the drying process, solvents evaporate through the paint film giving it a brownish colouration. Knot bleeding is not the same as resinous exudation which occurs under heat or sun. In such case, the resin oozes through the coating giving it a yellowish colouration after a few months.

Solutions

Seal bare wood knots with a shellac. Apply a solvent-based primer-sealer.


Resinous exudation on soft wood knots

Causes

Knots and sap veins in several soft woods such as pine, spruce and fir exude resin under heat or sun. Resin oozes through the coating giving it a yellowish colouration after a few months.

Solutions

None. Resinous exudation cannot be stopped. It only ceases when there is no more spew in the knots. To remove resin, heat knots and scrape excess resin. Remove afterwards all residues with alcohol, turpentine or Polyprep 875-104.

Resinous exudation is not the same as bleeding. It occurs mainly on wood containing tannic acid and resin (pine, spruce and fir). The solvents in coatings dissolve tannic acid and resin. During the drying process, solvents evaporate through the paint film giving a brownish colouration to coatings.

Darker shades promote resinous exudation.


Rising of colourants

Causes

Some colourants, usually lighter, naturally rise to the surface as small stains.

Paint improperly shaken.

Solutions

This phenomenon does not alter the product during application.

Mix the product properly before use.


Skinning in the container

Causes

Overly high temperatures or significant temperature variations during storage.

Pressure triggered by the coating inside the container reacting to water or humidity.

Solutions

Check the room temperature. The product should not be exposed to extreme heat.

Carefully open the container to release pressure.


Colour too dark (for exterior stains)

Causes

Porous or absorbing wood. Each wood species absorbs stain differently.

Water-based stain which dried too rapidly.

Poor selection of tools.

Application temperature.

Solutions

Run a complete application test on a piece of wood identical to the one used for your project. If results are satisfactory, apply the solution on all the surfaces. Otherwise, choose another colour or mix other colours.

Choose appropriate tools.

Apply stain at the recommended temperature.


Fish eyes (crawling)


Small rings which appear on the paint surface and which indicate a lack of compatibility between the surface and the coating.

Causes

1. Contaminated surface:oil, silicone.

2. Use of a contaminated airless gun.

3. Contaminated product.

Solutions

1. Sand affected areas, clean surface and apply new coat.

2. Sand affected areas, clean surface and apply new coat after cleaning the gun.

3. Sand affected areas, clean surface and apply new coat.

If fish eyes appear on the whole surface, remove the coat and apply a new coat to get an even paint film.


Lack of adherence during application (Roll-up)

Causes

Product incompatibility.

Contaminated surface.

Use of a flat for ceilings coating as a base coat on walls.

Solutions

Apply a second coat and a third coat, if required.

Remove coating, clean the surface, and reapply the product.

Apply a base coat and two finishing coats. Never use a flat for ceilings coating as a base coat for walls.

Make sure that the base coat and the paint come from the same manufacturer.


Lapping (visible lap marks)

Non-uniform appearance of the coating surface, such as roller or brush strokes.

Causes

Application of a coating while exceeding the open time limit.

Inappropriate tools.

Coating applied at overly high temperatures.

Large crossing surfaces.

Solutions

Comply with the open time limit of the product.

Use the appropriate tool.

Check the room temperature. The product should not be exposed to overly high temperatures.

Use a fresh paint masking tape to divide the surface in small sections, and then apply the coating on one section at a time.


Low hiding power

Causes

1. Some colours contain organic pigments with lower hiding power.

2. Paint improperly shaken.

3. Over thinning.

4. Poor levelling and uneven spreading.

5. Use of low quality tools.

6. Paint absorption by an absorbing base.

7. Low quality product.

8. Application temperature was too high, which caused poor product levelling.

Solutions

1. Apply an additional coat or an appropriate base coat. For darker colours with low hiding power, apply GoPrime 150-135 or 160-135 depending on the icon on the colour chip.

2. Mix paint with a stirring stick down to the bottom of the container.

3. Do not dilute paint since it is formulated to be applied as is.

4. Apply paint uniformly and maintain the product’s spreading rate.

5. Use high quality tools. They make work easier and give better results.

6. Apply appropriate base coat.

7. Use better quality product.

8. Comply with the product’s application temperature.


Running

Dried drops visible on the surface.

Causes

1. Coating applied too generously.

2. Coating applied to thickly.

3. Over thinned coating applied.

4. A too cold surface.

5. Use of an airless gun too close to the surface.

Solutions

1. Redistribute paint excess on the surface using a brush or roller.

Optimal application temperature ranges between 15 °C and 25 °C (60 °F and 77 °F).

The coating should be thinned only if necessary.


Yellowing of fresh paint

A yellow colour which appears on the coating during the application or drying process.

Causes

1. Type of gypsum boards (drywall). New types of gypsum boards on the market occasionally complicate results obtained with various paints. Some recycled boards from the United States will turn yellow when covered with a primer-sealer and a latex paint. All the sections covered with a joint compound stay white, while the rest turns yellow.

2. Apartment improperly heated.

3. Joints poorly dried.

4. Lack of ventilation.

5. Use of varnishes that harden in a humid environment, causing the vapours to settle down on the paint. Fresh water-based paints when applied before a floor varnish will quickly turn yellow following the application of urethane-based varnishes which harden when expose to humidity. Their strong smell makes them easily recognizable.

Solutions

1. Clean the surface, apply a coat of primer Polyprep145-033, and then apply the finishing product.

2. In the case of humid gypsum, heat up the apartment and the yellowing will eventually disappear.

3. The blackening of joints indicates a mildew problem. In such a case, reapply a joint compound on the surface before repainting. Otherwise, let joints dry completely before painting, apply a coat of primer Polyprep145-033, and then apply the finishing product.

4. Ventilate the room, apply a coat of primer Polyprep145-033, and then apply the finishing product.

5. Clean the surface, apply a coat of primer Polyprep145-033, and then apply the finishing product.

If you apply a varnish that hardens in a humid environment, leave the house for a few days, and remove plants and perishable foods. When you return home, make sure to properly ventilate the room(s).


Peeling from masonry

Causes

1. Efflorescence.

2. Excessive humidity.

3. Hardening sealant – floor.

4. Very smooth surface – floor.

5. Contaminants.

6. Wrong product selection – garage floor.

7. Application in the sun, causing solvents to evaporate too quickly.

8. Accumulation of paint layers.

9. Water infiltration under the paint film.

10. Old plaster, very dry and powdery.

Solutions

1. Clean surface, remove lifted coating, clean again and apply appropriate coating.Correct humidity problems if required.

2. Clean surface, remove lifted coating, clean again and apply appropriate coating.

3. Remove hardening sealant or build a raised floor.

4. Clean surface, remove lifted coating, clean again and apply appropriate coating.

5. Clean surface, remove lifted coating, clean again and apply appropriate coating.

6. Clean surface, remove lifted coating, clean again and apply appropriate coating.

7. Clean surface, remove lifted coating, clean again and apply appropriate coating.

8. Clean surface, remove lifted coating, clean again and apply appropriate coating.

9. Clean surface, remove lifted coating, clean again and apply appropriate coating.

10. Remove lifted coating, clean surface, apply a solvent-based primer, makenecessary repairs, then apply the solvent-based primer again and the appropriate finishing coats.

Wait 28 days before painting fresh concrete.

Use muriatic acid to eliminate efflorescent salts and engrave smooth concrete floors.

Preferably use a water-based product on masonry, except on old powdery plaster.

Run a humidity test before covering a concrete floor.

Check surface temperature. It must match room temperature.

Avoid painting if surface humidity content exceeds 6 %.


Peeling from wood

Causes

1. Inadequate sanding.

2. No primer on shellac.

3. Application in the sun, causing solvents to evaporate too quickly.

4. Paint film altered by an additive: drying agent, oil…

5. Wrong product selection.

6. Excessive wood humidity: close to vegetation, humid soil, etc.

7. Temperature and humidity variations.

8. Water infiltration under the paint film.

9. Contaminants: patina, mildew, soot, etc.

10. Lower flexibility of paint film.

11. Accumulation of paint layers.

Solutions

1. Also for causes 2-11:

Correct humidity problems if required. Clean, strip and sand surface, then apply coating.

To prevent water infiltration, verify the sealant quality.

Avoid painting directly under the sun.

Check surface temperature. It must match room temperature. Optimal application

temperature is between 15 °C and 25 °C (60 °F / 77 °F). Outdoors, avoid painting if the wood moisture content exceeds 12 % (latex stains 18%).

Paint the 6 faces of the wood and saturate the wooden boards’ extremities with coating. This keeps the wood from absorbing excessive humidity, which hinders coating adhesion.

Use the wood renovator to eliminate patina.

Use household bleach to eliminate mildew.

Use a solvent-based primer on surfaces repaired with shellac.


Peeling from gypsum (drywall)

Causes

1. Poor surface preparation.

2. Contaminants.

3. Water infiltration under the paint film.

Solutions

1. Also for causes 2-3:

Sand and clean affected areas, then apply a primer and two finishing coats. Correct humidity problems if required.

Apply a water-based primer on bare gypsum.


Lack of adherence on synthetic surfaces

Causes

1. Smooth and non-porous surface.

2. Contaminated surface.

3. Painted under the sun.

4. Excessive humidity.

5. Temperature variation.

6. Wrong product selection.

7. Water infiltration under the paint film.

8. Lower flexibility of paint film.

9. Paint film altered by an additive: drying agent, oil…

Solutions

1. Also for causes 2-9:

Clean and sand affected areas, then apply a solvent base coat and two finishing coats.

Correct the humidity problem if required.

Check the surfaces’ temperatures, which must match room temperatures. Optimal temperature for application is between 15 °C and 25 °C (60 °F and 77 °F).

Apply a 100 % acrylic, water-based paint on vinyl wall coverings (maximum adhesion is reached after several weeks).

Check waterproofness of the sealant before painting.

Use Polyprep 145-033 on ceramics, glass and plastics.


Whitening

Causes

1. Substrate affected by dew, rain or humidity during the drying time. In such conditions,solid colour coatings become flat, and transparent coatings become whitish or greyish.

2. Prolonged presence of water on water-based varnish.

3. High humidity during application or drying of clear water-based sealant.

Solutions

1. Sand affected areas and apply a new coat. If the surface is badly damaged, remove the coating and start over again.

2. In the case of a minor problem, sand the surface lightly and apply a new coat. If the problem is major, sand the surface and start over again.

3. Allow the sealant to dry: it should recover its clarity.

Let the product dry for 2 to 3 hours before any sign of rain or dew. Comply with the application temperature as well as the humidity rate recommended for this product.

Use a solvent-based varnish on tables used for eating.


Lapping (visible lap marks)

Causes

1. Coating poorly applied. On affected areas, opaque coatings seem glossier and semi-transparent coatings appear more opaque.

Solutions

1. In the case of opaque coatings, clean, sand and paint the surface over again by following the application methods recommended for the product. For semi-transparent coatings, lapping cannot be eliminated: strip, sand and repaint.


Uneven colour (exterior stains)

Causes

1. Due to their porosity, softwoods such as pine absorb stain unevenly.

2. Uneven sanding.

3. Uneven spreading.

Solutions

1. Sand bare wood surface. If you have to apply a water-based stain, use water to even out the wood cellular structure and apply the stain according to the spreading methods recommended in this course.

2. Using a sanding block or an electric finishing sander, sand the surface evenly with a 180 abrasive paper.

3. Spread the stain evenly with a wet lint-free cloth properly wrung out. Avoid excessive scrubbing.

 

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