In order to help our customers, we provide some useful information about paints. By pressing the links below you can find out :
Craters and water marks on the surface of the paint film caused by rain or heavy condensation.Probable Causes:
Rain falling on a freshly painted surface causes craters to form on the surface before it has hardened sufficiently.Prevention:
Allow coating (where practicable) to surface harden prior to exposure to rain or heavy condensation.Repair:
Abrade, clean all surface damage areas and apply overall undercoat and or topcoat.
Very large (macro) checking or cracking which resembles the skin of an alligator or crocodileProbable Causes:
Where the surface shrinks faster than the body of the paint film. Can be caused by excessive film thickness and limited paint flexibility.Prevention:
Use correct coating specification and materials. Avoid excessive thickness. Avoid application at high ambient temperatures.Repair:
Repair will depend upon size and extent of alligatoring. Abrade or remove all affected coats and apply suitable undercoat and topcoat.
Staining of a paint film by diffusion of a soluble coloured substance from the underlying paint to give undesirable discoloration.Probable Causes:
Bleeding can happen when strong solvents are used in the topcoats.Prevention:
Use correct coating specification and materials. Use compatible materials. Use appropriate sealer coat.Repair:
Remove stained or contaminated layer. Apply a suitable sealer coat which will not dissolve soluble.
Total loss of colour of a coating.Probable Causes:
Bleaching due to weathering or chemical attack.Prevention:
Use colour stable pigments or a system which will withstand the chemical environment.Repair:
Remove bleached coating or abrade the surface and recoat using a more suitable coating system.
Dome shaped projections or blisters in the dry paint film through local loss of adhesion from the underlying surface. Blisters may contain liquid, gas or crystals.Probable Causes:
Localised loss of adhesion caused by contamination with grease, oil, salts, trapped moisture, retained solvent, hydrogen pressure ( on coatings used with cathodic protection ), soluble pigmemts etc. Osmotic blistering can occur in immersed conditions.Prevention:
Ensure correct surface preparation and application. Apply a suitable coating system.Repair:
Depending upon size and type of blistering, remove blistered areas or entire coating system and repair or fully recoat.
A hazy deposit on the surface of the paint film resembling the bloom on a grape, resulting in a loss of gloss and dulling of colour.Probable Causes:
Paint film exposed to condensation or moisture during curing, (common phenomenon with amine cured epoxies). Incorrect solvent blend can also contribute to blooming.Prevention:
Apply and cure coating systems under correct environmental conditions and follow the manufacturer's recommendations.Repair:
Remove bloom with clean cloth or suitable solvent cleaners. If necessary, apply undercoat/topcoat following coating manufacturer's recommendations.
A friable, powdery layer on the surface of a paint film. A change of colour or fading is also seen. Chalking rates vary with pigment concentration and choice of binder. Chalking is a known characteristic of certain paints e.g. epoxy paints.Probable Causes:
Disintegration of the paint binder on exposure to weathering and/or UV light.Prevention:
Apply a topcoat with high resistance to chalking, such as a polyurethane of acrylic.Repair:
Remove all powdery deposits by abrasion or light sweep blast cleaning, wipe loose material off and apply a chalk resistant topcoat.
The formation of small bowl shaped depressions in the paint film.Probable Causes:
Trapped air bubbles which have burst to leave small craters as the coating dries. The coating has insufficient time to flow into a uniform film.Prevention:
Improve spray technique to avoid air entrainment. Add thinners as recommended by the paint supplier.Repair:
Abrade and clean the surface and recoat.
The development of loosely coherent pigment agglomerates in a coating materialProbable Causes:
Non-uniform pigment dispersion which results in the pigments forming agglomerations. Unsuitable thinners or inadequate mixing.Prevention:
Ensure only properly formulated and mixed products are used. Use recommended thinners. /p>Repair:
Remove coating where flocculation is visible. Abrade and clean the surface and apply a properly formulated and mixed coating system
Paint and coating spray and debris onto a surface that was not intended to be the target.Probable Causes:
Poor workmanship, inadequate masking, wrong spray equipment.Prevention:
Correct methods of cutting in with the use of rollers and brushes before spray applicationRepair:
Depends upon type of coating and substrate. Can usually be removed immediately with solvents or cleaners, high pressure water washing and/or abrading. Prevention is better than cure in this case.
The formation of minute holes in the wet paint film during application and drying, due to air or gas bubbles which burst, giving rise to small craters or holes which fail to coalesce before the film dries.Probable Causes:
Solvent or air entrapment within a paint film. A common problem when coating porous substrate such as zinc filled primers, zinc silicates and metal sprayed coatings etc. Pinholes can also be caused by incorrect spray application or incorrect solvent blend.Prevention:
Use correct application techniques with suitably formulated products. Correct solvent blends and environmental conditions. Check spray equipment and distance of spray gun from the surface.Repair:
Abrade, clean overall and apply suitable tiecoat/undercoat and topcoat as necessary.
Solvent ( clear ) bubbles on the surface of the paint film soon after application.Probable Causes:
Incorrect solvent blends, porous surfaces and wrong environmental conditions.Prevention:
User correct coating specifications and materials. Correct application techniques and environmental conditions.Repair:
Lightly abrade and clean the surface and apply undercoat/topcoat.
A defect which appears soon after application due to pigment separation. The visual appearance is a deepening of the colour. The affected area dries to a deeper shade than the remainder of the surface.Probable Causes:
Pigment separation and settlementPrevention:
Use correctly formulated productsRepair:
Lightly abrade and clean and then recoat with a suitably formulated material.
Occurs in coloured materials containing mixtures of different pigments. It closely resembles flooding, although a mottled or streaky effect is produced when the different pigments separate.Probable Causes:
The mottled effect, which is visible to the eye, is caused by separation of the different coloured pigments. It may also result from the addition of excessive thinners.Prevention:
Use correctly formulated products. Do not over thin with solvent.Repair:
Abrade and clean overall and apply a suitable sealer or topcoat.
The quality of surface preparation, and surface repair on new, or repainted surfaces, significantly affects the quality of painting, and in some cases supersedes the importance of quality of the paint. Surface preparation and surface repair are the most important requirements for maximum durability of any paint system. Since, the first coat of paint can, quickly conceal the quality of surface preparation and repair, the effects are not usually evident until premature paint failure occurs.
The first step should always be a thorough examination of the surface to be painted, checking for peeling and faded paint, dirt, chalking, grease, cracking, knots, bare areas, mildew, rust, stains and structural problems. All surfaces, whether painted or unpainted, must be clean, free from grease, sound and dry prior to finishing.
LOOSE AND PEELING PAINT: Remove as much loose and peeling paint by scraping, wire brush or power-washing the surface. Feather-sand rough edges smooth until they blend with bare surface.
DIRT, GREASE, OIL & CHALK :: Remove these deposits by washing with a detergent solution or commercial cleaner recommended for cleaning painted surfaces using a sponge or brush. Power washing is also a fast, effective method of removing dirt, chalk, etc.
MILDEW:Spotty patches that look like dirt, but do not come off when scrubbed with detergent solution, are probably mildew. Mildew can occur on any side of the house, but is more likely to grow in shaded areas or behind shrubbery. It can easily be identified from other forms of discoloration by applying a few drops of bleach. If mildew is present, the black, grey or brown colour will bleach out and disappear within one or two minutes. Mildew must be killed and removed before repainting. If the mildew is not completely removed, the active spores will continue to grow and may almost immediately begin to reappear on a recently repainted surface. Where mildew is present, apply a solution of one part household bleach and three parts water, or use a commercial mildew remover.
RUST:Remove all rust by sandblasting, wire brush, steel wool, or sandpaper. See Iron, Steel and Ferrous Metal section for SSPC preparation methods.
CRACKS, SPLITS AND OPEN JOINTS: Cracks, or open joints, where water may enter should be caulked with a high-quality, paintable acrylic caulk. Apply primer over caulked area.
GLOSSY SURFACES: Always dull surfaces with sandpaper.
Maintenance painting will frequently not permit complete removal of all old coatings prior to repainting a particular surface. Recognize that any surface preparation, short of removal of all old coatings, may compromise the service life of the new coating system. Check compatibility of previously painted surfaces using a test patch with the coating if there is any doubt on re-coatability.
NEW: Wipe clean with mineral spirits to eliminate any oil or grease. Remove all rust and mill scale. Prime with a good oil-based metal primer
PREVIOUSLY PAINTED IRON AND STEEL:: If the old film is in good sound condition, all that needs to be done is to de-gloss the old surface with light sanding and clean with mineral spirits. If the old film is in poor condition, it should be removed with paint remover. If metal has rusted, that too must be removed. Prime all bare spots with oil-based metal primer
WHITE METAL BLAST CLEANING (SSPC-SP5, NACE No. 1): A surface with a gray-white, uniform metallic color, slightly roughened to form a suitable anchor pattern for coatings. This surface is free of all oil, grease, dirt, mill scale, rust, corrosion products, oxides, paint and other foreign matter.
NEAR-WHITE BLAST CLEANING (SSPC-SP10, NACE No. 2): A surface from which all oil, grease, dirt, mill scale, rust corrosion products, oxides, paint or other foreign matter have been removed except for light shadows, streaks or other discolorations (of oxide bonded to metal). At least 95% of any given square inch has the appearance of "White Metal," and the remainder is limited to slight discolorations.
COMMERCIAL BLAST CLEANING (SSPC-SP6, NACE No. 3): A surface from which all oil, grease, dirt, rust scale and foreign matter have been removed except for slight shadows, streaks or discoloration caused by rust stain or mill scale oxide binder. At least two-thirds of any square inch shall be free of all visible residues and the remainder shall be limited to light discoloration, slight staining, or light residues mentioned above. If the surface is pitted, slight residues of rust or paint are found in the bottoms of the pits.
BRUSH-OFF BLAST CLEANING (SSPC-SP7, NACE No. 4): A surface from which oil, grease, dirt, loose rust scale, loose mill scale and loose paint are removed, but tightly adhering mill scale, rust, paint and coatings are permitted to remain if they have been exposed to the abrasive blast pattern, so that numerous flecks of the underlying metal are uniformly distributed over the entire surface.
WATER BLASTING (NACE No. RP-01-72): ): Removal of oil, grease, dirt, loose rust, loose mill scale and loose paint by water at pressures of 2000-5000 psi at a flow of 4-14 gallons per minute.
HAND TOOL CLEANING (SSPC-SP2) & POWER TOOL CLEANING (SSPC-SP3):These specifications describe methods of preparing metal surfaces by removing loose mill scale, loose rust and loose paint by wire-brushing, sanding, scraping or chipping with hand or power tools.
NEW OR UNPAINTED CONCRETE FLOORS: Floors - Check for any dampness on floors by placing a rubber mat down and leaving overnight. Upon inspection, if dampness occurs on the back side of the mat, or concrete surface has been darkened by moisture - Do Not Paint. New concrete should be allowed to cure 21 days at 30ºC. prior to painting.
Your first coat of paint should be a thinned-down version of your finish. Thin 1:5 water or solvent: paints. The topcoat should be used straight out of the can.
PAINTED CONCRETE OR WOOD FLOORING:Be sure surface is free from dirt, dust, etc. by sweeping or vacuum cleaning. Remove grease, oil, floor compound and wax by chemical cleaning. Scrape carefully to remove deteriorated coatings. If remaining coating is glossy or very hard, sand it lightly for good adhesion of subsequent coatings. The surface must be thoroughly dry before coating.
UNPAINTED PUTTY AND BRICK:This needs no special preparation. However, putty should be allowed to dry thoroughly before it is painted. Apply two coats of exterior latex paint formulated for masonry.
PAINTED PUTTY:Should be cleaned and free from loose paint and all holes should be patched. Paint with exterior latex.