| Bleeding |
When the upper coat is discolored by the lower coat diffusing into it.
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| Bloom |
White milky appearance on film. Caused by thinners evaporating too fast in high humidity. Water condenses on cold surface. May disappear on heating. Polar solvents can help in reducing or eliminating.
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| Blushing |
White milky appearance or haziness in film caused by the condensation of water on the surface. Caused by thinners evaporating too fast in high humidity. May disappear on heating. Polar solvents can help in reducing or eliminating.
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| Chalking |
Formation of a friable powder on the surface of a coating giving a chalky appearance. Caused by disintegration of the binder by weathering (oxidation and or UV degradation) and release of the pigments and/or extenders at the surface. The "Chalk" can be removed from the surface by rubbing which reveals the original colour beneath. If left the chalk will generally reappear.Formation of a powdery surface while spraying. This caused by too much fine overspray usually from too high a pressure at atomisation and thinners evaporating too fast between the gun nozzle and the job. The fine aerosol formed looses its solvent and is deposited in an almost dry form on the surface. Poor air extraction exacerbates the problem. The preferred term is "DRY SPRAY".
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| Corrosion |
Decomposition of a metal substrate in contact with its environment.
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| Cratering |
Small holes in the surface. Caused by oil, grease or substrate contamination.
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| Crawling |
The tendency of the paint film to recede from areas usually caused by a dirty substrate.
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| Cure |
The process of the paint from liquid to solid
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| Distinctness of Image (DOI) |
The assessment of the gloss level of a coating system by the sharpness of an image reflected.
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| Etching |
Using alodine or other acidic chemical solution to prepare the surface for primimg by removing a layer of base metal.
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| Fading |
The loss of colour caused by a change in the colourant used in the film (pigment or dye). Generally the colour becomes lighter but any more resistant colourants will dominate.
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| Fish-eyes |
Small holes in the surface. Caused by oil grease or silicone contamination.
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| Flash Off |
The time between coats that is necessary to allow evaporation of solvents.
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| Floating |
The separation of pigments that result in a mottled, blotchy or streaked appearance in the paint film
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| Flooding |
Pigment settlling that causes a uniform color change
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| Gassing |
The formation, in the can, of gaseous products in a coating material, due to the reaction between two or more constituents of the coating material or between the latter and the metal of the container. Occurs in paints containing aluminium metallic pigments if moisture is present or acidity is too high or catalysts exposed to high humidity
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| Hard Dry |
When a thumb (or substitute thereof) , exerting a measurable downwards pressure, leaves no permanent mark or damage on the coating film. It is the stage when the. paint film can be handled without damage.
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| Hardness |
The ability of a coating film, as distinct from the substrate, to resist cutting, indentation or penetration.
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| Haze |
Haziness in film. Low DOI or gloss. Generally caused by wrong balance in thinners, diluent/solvents or heavy humidity.
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| Mar Resistance |
The ability of a coating to resist damage caused by light abrasion, impact or pressure.
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| Micro-blistering |
Tiny air blisters just beneath the film surface mostly caused by moisture
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| Mottling |
Uneven effect in metallic finishes. Caused by heavy wet coats. Build-up of electrostatic charges. Poor mixing of paint. Conditions too cold. Uneven spraying techniques.
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| Non-volatile |
The solid material that does not evaporate.
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| Opacity |
The degree to which a material obscures or hides a substrate.
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| Orange Peel |
Surface mottled like skin of an orange. Caused by poor flow. Coats too thick. Surface drying too quick. Poor atomisation.
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| Pin Holing |
Small holes in film. Solvent trapped under film due to uneven solvent evaporation.
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| Pot Life |
The sprayable life of a coating after it has been mixed.
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| Runs |
Running of wet paint into uneven rivulets. Cause - paint too thin. Solvents very slow. Very cold conditions. Too much paint applied.
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| Sags |
Partial slippage of paint. Thick areas like wide runs. Cause - Heavy thick coats. Gun too close. Badly adjusted gun.
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| Shelf Life |
The amount of time an unopened can of coating can be stored and then used.
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| Skinning |
The formation of an insoluble layer of hardened paint on the top of a coating material in the can. Commonly caused by a chemical reaction due to moisture in the air.
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| Solvent Popping |
The formation of small holes in the paint film. Caused by moisture in air or solvent trapped under film. May occur if the second coat has been accelerated more than the first.
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| Substrate |
Any surface to which a coating is applied
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| Surface Dry/ Dry to Touch |
The state of drying when slight pressure with a finger does not leave an imprint or reveal tackiness; when dry sand applied according to a standard method can be brushed off the coating without sticking to or causing damage to the surface,
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| Telegraphing |
When the substrate surface is revealed through the coating after cure.
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| Viscosity |
The internal resistance to flow possessed by a fluid; the rate of flow of a material when a force is applied to it .
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| Water Spotting |
the result of water standing on the paint film or substrate that changes the surface appearance.
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| Wet Edge |
The ability to blend a wet coating smoothly with overlap areas during application.
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| Wrinkling |
When the film surface skins and absorbs liquid within the film.
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