Carvél Painting Glossary U-Z
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ULTRA DEEP BASE - Paint base used to develop deep intense colors with no apparent white.
ULTRAVIOLET (UV) - A band of electromagnetic radiation, part of which is especially destructive to paint films.
UNDERCOAT - Any coat applied after the primer and prior to the finish coat; an intermediate coat. An undercoat may be used on wood trim and some metals where exceptional smoothness is desired.
UNDERCUTTING - The gradual penetration and spread of corrosion beneath a coating from a break or pinhole in the film or from unprotected edges.
UNDERFILM CORROSION - Corrosion that occurs between a coating and the metal substrate without a break in the coating layer.
UNIVERSAL COLORANT - Tinting colors formulated to be compatible with a wide variety of solvent-thinned and water-thinned paints.
UPPER EXPLOSIVE LIMIT (UEL) - The concentration at ordinary ambient temperatures of a compound in air above which an explosion will not occur if the mixture is ignited. The concentration is expressed as a percent of the gas vapor in air by volume. When the concentration is below the upper explosive limit and above the lower explosive limit (LEL), the mixture will burn and explode. See also LOWER EXPLOSIVE LIMIT.
URETHANE ALKYD (URALKYD) RESIN - Alkyd resin system modified with isocyanate. This modification can decrease drying time and enhance resistance to chemicals, moisture, weathering, and abrasion of the alkyd resins.
URETHANE COATING - A coating whose vehicle contains a polyisocyanate monomer reacted with various other materials. Urethane coatings can be obtained as air-drying, moisture-cured, or catalyzed types.
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VACUUM BLASTING - An air abrasive blast cleaning system equipped with an enclosure around the abrasive stream and a vacuum to remove spent abrasive and debris as the blasting is being done. See also CLOSED ABRASIVE BLAST CLEANING.
VACUUM-SHROUDED POWER TOOL - Power tool equipped with a vacuum shroud to capture dust, debris, and other materials while they are being generated and prevent them from escaping into the environment.
VALUE - The lightness or darkness of a color.
VARNISH - A liquid composition that is converted to a translucent or transparent solid film after application in a thin layer. See also OIL VARNISH, SPAR VARNISH.
VARNISH MAKER'S AND PAINTER'S (VM&P) NAPHTHA - A hydrocarbon solvent mixture composed of aliphatic compounds.
VARNISH STAIN - A varnish containing a stain.
VEGETABLE OIL - Drying oil obtained from the seeds or nuts of vegetables. Examples are linseed, soybean, and tung oil.
VEHICLE - The liquid portion of paint in which the pigment is dispersed. It is composed of binder and solvent.
VINYL ALKYD RESIN - Alkyd resin system modified with vinyl. This modification can enhance the recoatability, moisture resistance, and chemical resistance of the alkyd resin.
VINYL FABRIC - A wallcovering made from a vinyl resin, available in a variety of textures and patterns.
VINYL RESIN - A synthetic resin made from vinyl compounds. Vinyl acetate is commonly used in latex paints. Polyvinyl chloride is used in some solvent-thinned coatings where high chemical resistance is needed. There are many other vinyl derivatives that appear in various specialized coatings.
VISCOSITY - The fluid thicknesg of a liquid coating material. A high viscosity coating is thick; a low viscosity coating is thin.
VOID - See HOLIDAY.
VOLATILE - (1) The easily evaporated components of any coating composition in contrast to the nonvolatile components. [Paint/Coatings Dictionary] (2) Any liquid that evaporates quickly.
VOLATILE CONTENT - Percentage of materials in a coating that evaporate.
VOLATILE QRGANIC COMPOUND (VOC) - Any organic compound which participates in atmospheric photochemical reactions except for those designated by the EPA as having negligible photochemical reactivity.
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WALLBOARD - Building material such as plasterboard or plywood used for interior walls.
WALLCOVERING - Any type of paper, vinyl, fabric, or specialty material that is pasted onto a wall or ceiling for decoration and/or protection. Wallcoverings come in a wide array of colors, patterns, textures, and performance characteristics, such as washability and abrasion resistance.
WALLCOVERING ADHESIVE (PASTE) - Adhesive material in powder or premixed form used to apply wallcovering to a substrate. Some wallcoverings are prepasted in the factory, and the adhesive in activated before application.
WALLCOVERING, TEXTILE - Fabrics such as linen, cotton, velour, chintz, silk, and felt, which are used unbacked or paper-backed for wallcovering.
WASHABILITY - Ease with which dirt can be removed from a paint (or wallcovering) surface by washing; also refers to the ability of the coating to withstand washing without removal or substantial damage.
WASH PRIMER - A thin, acid-modified pretreatment generally applied to aluminum or galvanized surfaces to enhance corrosion resistance and adhesion of subsequent coatings. Also called etch primer.
WATER-BASED COATING - See WATERBORNE COATING.
WATER BLAST CLEANING - A form of blast cleaning welding process that stick to the surface near the weld.
WET ABRASIVE BLAST CLEANING - Adding water to an abrasive blast cleaning operation by injection of water into the abrasive stream or external application of water to the abrasive stream as it exits the blast nozzle. The term also is used to describe injection of abrasive into pressurized water for blasting.
WET EDGE TIME - Length of time that a wall paint can stand and be brushed or rolled back into the next stretch without showing lap marks.
WET EILM THICKNESS (WFT) - Thickness of a liquid film immediately after application; often measured with a wet film thickness gauge and expressed in mils or microns.
WET FILM THICKNESS GAUGE - Tool for measuring wet film thickness.
WET-HIDING - The hiding ability of a wet coating after application and before it dries. See also DRY-HIDING.
WATERBORNE COATING - Latex paint and paint containing a water-soluble binder. See also WATER-DISPERSIBLE COATING.
WATERBORNE STAIN - Solution of dye, water, and alcohol.
WATER-DISPERSIBLE COATING - An organic coating which normally is solvent-borne, but by adjusting the chemistry can be dispersed in water.
WATER JETTING - Using water at high pressure (10,000 to 25,000 psi) or ultra high pressure (greater than 25,000 psi) to clean a surface. Abrasive may be injected into the water jetting stream to increase the cleaning power and to roughen the surface.
WATER-THINNED COATING - A coating that is waterborne and uses water for thinning. The binder may be a material that requires water for setting, that is soluble in water, or that is emulsifiable in water.
WAX - Any of a group of materials used for polishing woodwork after staining or finishing. Waxes generally are soluble in common solvents, and offer protection for a surface against water and impact. Carnauba, candelilla, and beeswax are examples.
WELD SPATTER - Metal beads produced during the
WHEEL BLAST CLEANING - See CENTRIFUGAL BLAST CLEANING, CLOSED ABRASIVE BLAST CLEANING.
WHIP CHECK - Safety cable that connects air hoses across a coupling to keep the hoses from flying around if the connection separates.
WHITE METAL BLAST CLEANING - Highest grade of blast cleaning. According to Steel Structures Painting Council Surface Preparation Specification No. 5, "White Metal Blast Cleaning" (SSPC-SP 5), a white metal blast cleaned surface is free of all visible oil, grease, dirt, dust, mill scale, rust, paint, oxides, corrosion products, and other foreign matter. White metal blast cleaning also is defined in NACE No. 1, "White Metal Blast Cleaned Surface Finish."
WIRE BRUSH - A hand tool or a power tool attachment made of wire bundles used to clean dirt, loose rust, loose paint or varnish, plaster spatter, and other debris from a surface.
WIRE BRUSH CLEANING - Cleaning a surface with a wire brush that is either a hand tool or a power tool.
WIRE ROPE - Cable made of steel strands wrapped around a core, and often used in rigging and scaffolding.
WIRE SEAM - A wallcovering seam in which the edge of one strip of wallcovering overlaps the next very slightly (about 1/16 inch).
WOOD - Lumber, usually classified as being hardwood or softwood and having open grain or closed grain.
WOOD FTI LER - A material in liquid or paste form used to fill cracks or holes in wood during surface prepara- Lion.
WORK CAGE - A single-point adjustable suspension scaffold unit enclosed with guards, midrails, and toe-boards, and large enough for the operator to work standing up. It allows access to work areas not easily reached by larger scaffolding systems.
WORK MIX - The mixture of various sizes of abrasive material that results from the periodic addition of new abrasive to recycled abrasive during a blast _cleaning operation. Sometimes called operating mix.
WRINKLING - A defect that causes small furrows or ridges in a coating film.
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YELLOWING - Development of a yellow color or cast as a result of aging or chemical attack.
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ZINC DUST - Finely divided zinc metal, gray in color. Used mainly in metal primers, especially for galvanized iron.
ZINC-RICH PRIMER - A primer for ferrous metals, incorporating zinc dust at a concentration sufficient to make the dried film electrically conductive, thus providing cathodic protection to the ferrous substrate. See CATHODIC PROTECTION.
