Finishing Terms & Definitions

[A]

TERM	DEFINITION
Abrasion Resistance	Ability of a coating to resist degradation caused by mechanical wear (mechanical erosion) due to its ability to dissipate the applied mechanical energy. Abrasion resistance can be enhanced by incorporation of surface modifying additives (see surface conditioners and surface modifiers). Abrasion resistance is not necessarily related to hardness as believed by some, but is more clearly comparable with toughness.
Accelerated Weathering	A test designed to simulate but at the same time intensify and accelerate the destructive action of natural outdoor weathering.
Accelerator	A substance used in small proportions to increase the speed of a chemical reaction. Accelerators are used to hasten the curing of a coating system. Also known as catalyst.
Acrylic	A family of synthetic resins made from acrylic acids.
Acrylic Latex (paint)	Water-reducible paint made with a binder that has acrylic as some portion of the composition. Other modifiers of the binder that may be added to reduce cost or add specific properties include styrene, epoxy, and polyvinyl acetate (PVA).
Acrylic Resin	A clear resin made by the polymerization of acrylic monomers such as acrylates Methyl, Ethyl, Butyl or acrylic acid.
Activator	The curing agent of a two component/compound coating system.
Adhesion	The degree of attachment between a film forming finish and the underlying material to which it is in contact without blistering, flaking, cracking or being removed by tape. The two surfaces are held together by interfacial forces which may consist of valence forces and/or interlocking/mechanical action. Mechanical Adhesion – An interlocking of two materials because of shape, texture, etc. causing the two materials to remain affixed one to the other. Also known as tooth. Chemical adhesion – A chemical reaction of two materials that bonds the two together.
Adsorb/Adsorption	Refers to the process of one material attracting and holding molecules of another substance to the surface of its molecules.
Air-assisted airless	An airless spray system operating at lower fluid pressure, typically 300-400 PSI, that uses a small amount of air to shape the spray fan and eliminate the spray tails at the ends of the fan pattern. Used most often in production spraying settings where speed and quality are needed.
Air Cap/Air Nozzle	Perforated housing for directing the atomizing air at the head of an air spray gun. Atomizes the coating and shapes the fan.
Air Drying	A common form of curing a coating in which drying takes place by oxidation or solvent evaporation by simple exposure to air without heat or catalyst.
Air Entrapment	A defect caused by the inclusion of air bubbles in liquid coating film. Often caused by applying the finish too thick, too heavily, or excessive brushing without topping off.
Airless Spray	A spraying system in which coating is atomized using high hydraulic (fluid) pressure rather than compressed air.
Alcohol	A group of solvents of relatively high evaporation rate but with fairly low solvent strength. Commonly used as a solvent in shellac, NGR stains, dyes, inks, and lacquer. Alcohols include Methanol, Ethanol, Isopropanol, n-Butanol, Isooctanol, Methyl Isobutyl Carbinol, Isoamyl Alcohol, Isobutyl Alcohol, Cyclohexanol, and Methyl Cyclohexanol. NOTE - Methanol is highly toxic both in skin contact as well as by inhalation. Methanol is readily absorbed by the skin and can metabolize to formaldehyde then to formic acid. Methyl alcohol is also known as methanol, methyl hydrate, or wood alcohol.
Aliphatic Hydrocarbons	A class of organic solvents which are composed of open chains of carbon atoms. Aliphatics are relatively weak solvents. Mineral spirits, paint thinner, VM&P naphtha, Stoddard Solvent, petroleum naptha, petroleum distillate, cyclohexane, octane, pentane, nonane, kerosine, gasoline, and heptane, propane, butane, hexane are all aliphatic hydrocarbons.
Alkali	An aqueous liquid which has a pH value of between 7 and 14. A base or caustic material.
Alkyd Resin	A family of synthetic resins formed by the condensation of polyhydric alcohols with polybasic acids. May be regarded as complex polyester (thermoset).
Alligatoring	A form of paint failure in which cracks form on the surface layer only. It is caused by the application of a hard drying paint over a relatively soft paint or by the application of thick films, in which case the underlying surface remains relatively soft. It is also caused by the application of paint over unseasoned wood. As the name implies, an alligatored surface is one that resembles the hide of an alligator in that it is cracked into large segments. As the surface of the thick film dries it tends to shrink. The soft undried, bottom layers of the thick film allow the surface film to shrink thereby causing the alligatoring.
Ambient Temperature	Room temperature or the existing temperature of the surroundings.
Amine	Materials often used as curing agents for epoxy coatings.
Aniline (Acid) Dye	Synthetic transparent colors which dissolve in the solvent for which they are formulated (i.e., water, alcohol, or oil). Some dyes are reducible in multiple solvents.
Anti-blocking agent	Additive used to lessen the adhesion of coated surfaces to another surface. Acts by producing a slight roughening of the surface. Are typically finely divided, solid minerals, but some are waxes.
Antioxidant	Compounding material used to retard deterioration of coating films caused by oxidation, heat exposure, etc..
Application	Any process by which a coating is transferred to a surface to be finished. Techniques include padding, wiping, brushing, spraying, and dipping.
Aromatic Hydrocarbons	Aromatic Hydrocarbons derive their name from the "pleasant" odor attributed to many of these substances. The aromatic solvents are produced from the distillation of petroleum or coal tar. A class of relatively strong organic solvents which contain an unsaturated ring of carbon atoms. Not all molecules with ring (loop) structures are aromatic. Examples are Toluene (toluol), Xylene (xylol), Phenol, Benzene, Styrene, Diethylbenzene, Methylnaphthalene, Ethylbenzene.
Asphalt/Asphaltum	A black resinous material of petroleum origin.
Atomization	Formation of tiny droplets of liquid as in the spraying process. A finish that is properly atomized will produce tiny droplets mist like in appearance. A poorly atomized coating will consist of larger droplets that may not flow out to form a smooth, level film.

[B]

TERM	DEFINITION
Barrier Coat	A coating used to isolate a dye, stain, glaze, or topcoat either from the surface to which it is applied or a previous coating for the purpose of increasing adhesion, insuring compatibility, or isolating contamination. Also known as a tie coat.
Base-Color	The first color coat applied during many types of faux finishing techniques.
Binder	The nonvolatile portion of the vehicle of a coating which holds together the pigment particles and attaches them to the substrate.
Bleaching	The fading of a color toward white generally caused by exposure to chemicals or ultraviolet radiation. The use of one of the three wood bleaches to remove natural color, dyes, or water stains from wood.
Bleeding	The diffusion of color matter through a coating from underlying surfaces causing color change. Caused by a common solvency of the topcoat and the dye.
Blistering	The formation of blisters in coating films by the local loss of adhesion and lifting of the film from the underlying substrate.
BLO	Boiled linseed oil. One of the drying oils used to make conversion coatings like varnish.
Blocking	A coating's tendancy to adhere to itself on another freshly coated surface or to other substrates. Causes windows to bind, doors to stick and damage to finished surfaces when they’re contacted before the coating fully cures.
Block Resistance	The ability of a coating to resist sticking to itself when used on two surfaces that come into contact with each other or other surfaces.
Blooming	Unlike blushing, bloom forms after the coating has dried or cured. Presenting as a haze in the film (may be irridescent or bluish like an oil slick) of coating surfaces, it's caused by the exudation of a component of the coating such as oil plasticizer, uncured oil stain, or noncrosslinked coating constituent when the coated part is exposed to a cycle of heat, humidity, and cooling. Also caused when an acid cured coating (e.g., conversion varnish) is applied over a sealer that contains zinc stearate; the acid and zinc have a chemical reaction as the coating cures (may occur months after application).
Blotch/Blotching	Blotches are random areas on the surface of the wood that have adsorbed more of the dye, stain, or finish compared to other areas. The sharp contrast between dark and lighter areas on the wood surface is usually considered unattractive.
Blushing	A film defect which manifests itself as a milky appearance which is generally caused by rapid solvent evaporation or the presence of excessive moisture during the curing process. Blushing can be prevented by slowing down the drying/evaporation rate of the solvents in the coating by adding a retarder.
Blush Retarder	A thinner/reducer with slower drying properties.
Body	Used to describe the consistency or thickness/viscosity of the coating while in liquid form.
Bond	The adhesion of, or ability of, two items to stick to one another.
Bonding	The attachment between a coating film and the underling material to which it is applied.
Bounce Back	The rebound of atomized coating, especially when applied by conventional air spray methods. The air pressure used to atomize the coating bounces off the surface being sprayed keeping the material from attaching to the surface and it's lost as overspray.
Box Coat	Spraying the first pass in one direction and the second at a right angle to the first providing more even film distribution.
Boxing	Mixing of coatings by pouring from one container to another. When starting a large paint job, it's wise to intermix (box) the containers of paint to ensure they are all the same color and avoid slight variations from one container to another.
Bridging	When a finish forms a layer over a crack or void rather than filling it. Often seen as white or gray pores where the finish has bridged the pore rather than fill it.
Brittleness	The lack of resistance to cracking or breaking of a coating film when bent or flexed.
Bronzing	A coloration (often green) observed on a dyed surface that contrasts with the actual color of the dye. It's caused by a concentration of dye crystals left on the surface of the wood after the carrier evaporated. To fix the problem, wipe the surface with a rag wetted with the proper solvent or simply topcoat with a solvent-based coating.
Brushability	The ease of applying a coating by brush.
Brush marks	Ridges left after application of the coating by a brush due to poor flow, leveling or substrate wetting. Choosing the proper brush, using good technique, and thinning the coating as needed all work to reduce or eliminate brush marks.
Bubbling	A temporary or permanent film defect in which bubbles of air or solvent vapor are present in the applied film. See air entrapment.
Build	The wet or dry film thickness of a coating. See high build.
Bumps	High and low spots in a coating surface caused by unwanted flowing that occurs during curing. Caused by surface tension gradients that arise during curing.
Burn-in	Method of filling a defect in wood using a hot knife and a burn-in stick of resin or shellac. Also, the ability of a new coat of finish to partially dissolve the surface of the previous coat and attain a chemical bond creating a continuous film instead of multiple layers/coats.
Burnishing	The formation of shiny area on a finished surface as a result of rubbing.
Butyl Cellosolve	A registered, trademark name for ethylene glycol monobutyl ether. A slow evaporating, water miscible, relatively strong solvent. Commonly used as a lacquer retarder.

[C]

TERM	DEFINITION
Catalyst	An accelerator, activator or curing agent which chemically increases the rate of reaction in a coating. Not chemically consumed in the reaction (different from curing agent).
Caustic	A strong base or alkaline material.
Caustic Soda	A common name for sodium hydroxide (lye), a strong base or alkali.
Cellosolve	Proprietary name for ethylene glycol monobutyl ether. A slow evaporating, water miscible, relatively strong solvent. Commonly used as a lacquer retarder. Also know as Butyl Cellosolve.
Centipoise	One hundredth of a poise which is a unit of measurement for viscosity. Water at room temperature has a viscosity of 1.0 Centipoise.
Chalking	Formation of a powdery surface condition due to the disintegration of the surface binder or elastomer caused by weathering, fuel, or other destructive environmental factors (e.g., exposure to ultraviolet radiation). Results in a loss of gloss.
Checking	Cracks in the surface of a film finish.
Chipping	Small pieces of finish removed from the surface, typically a sign of physical damage incurred in shipping or handling. Color touch up followed by a compatible finish generally solves the problem.
Chemical resistance	A coating's resistance to damage from solvents, acids, and alkali.
Chlorinated Hydrocarbon	A class of strong, fast evaporating, nonflammable solvents such as carbon tetrachloride, methylene chloride or trichloroethylene.
Cissing	Small holes in the surface of the film finish caused by oil, grease or silicone contamination. (aka, fisheye, cratering).
Clean and Dry	Rather than a method, the requirement for Clean and Dry describes the condition of the surface prior to finishing. The surface shall be clean, dry, and free of oil, grease, wax, and any other contaminant that may affect the adhesion of the coating. Dry means that the substrate contains less than 15% moisture.
Cleaner	A detergent, alkali, acid or similar contamination removing material, which is usually waterborne.
Coal Tar	A dark brown to black bituminous material produced by the destructive distillation of coal.
Coal Tar Epoxy	A coating in which the binder or vehicle is a combination of coal tar and epoxy resins.
Coalescence	The formation of resinous or polymeric material when water evaporates from an emulsion or a latex system, permitting contact and fusion of adjacent particles; fusing or flowing together of liquid particles.
Coat	The finish applied to a surface in a single application to form a film when dry. The act of applying a finish to a surface.
Coating	Any material applied to a surface leaving a protective layer on that surface. Lacquer, polyurethane, varnish, paint, vinyl, acrylic, butyrate, and shellac are all types of coatings.
Coating defects	Defects of wet and consequent dry coating films affecting the coating's appearance and sometimes performance. Examples of coating defects include bubbles, craters, pinholes, orange peel, etc.
Coating System	A number of coats separately applied, in a predetermined order, at suitable intervals to allow for drying and curing, resulting in a completed job.
Cobwebbing	Premature drying of a coating during spraying causing a spider web effect.
Cohesion	The primary or secondary valence forces which bind the particles of a finish together into a continuous film.
Cold Checking	The cracking of a finish due to exposure to cold temperatures.
Color	Aspect of the dye, stain or paint that depends upon the spectral composition of the incident light, the spectral reflectance or transmittance of the film, and the spectral response of the observer, as well as the illuminating and viewing geometry.
Colorant	Dye, pigment, or other agent used to impart a color.
Color Fast	Nonfading; resistant to fading.
Color Retention	The ability to retain its original color during weathering or chemical exposure.
Color Wheel	A circular chart of pie shaped wedges that represent the visible color spectrum. Two color wheels are used in finishing; the artist's color wheel that presents primary and secondary colors and the finisher's color wheel that presents common earth tones.
Combustible Liquid	Any liquid having a flash point at or above 100 degrees F (37.8C)
Compatible	The ability to mix with or adhere properly to other coatings without detriment.
Compatibility	Ability of two or more coating components to mix with each other in a wet or dry state to form a homogeneous composition without specific negative interactions.
Complimentary Colors	Two colors directly opposite one another on the artist's color wheel.
Conical Mandrel	An instrument used to evaluate a coating's resistance to cracking when bent over a specified radius.
Contrasting Colors	Colors separated by at least three others on the color wheel.
Conversion Coating	Also known as reactive coatings, they cure by chemical reaction. This chemical reaction may be between the oxygen in the air and the constituents of the coating, or between a catalyst or accelerator introduced into the coating material by the finisher. Drying oils such as tung and linseed, varnishes, two-part finishes, etc. are all examples of reactive coatings. The word conversion is used because a non-reversible chemical conversion has taken place in order to produce a dry, hard film. This does not mean that solvents will not dissolve or just damage the coating, just that the damage is non-reversible. See Cure.
Copolymer	Large molecules obtained by simultaneous polymerization of different monomers, as in vinyl copolymers.
Corning	The build up of powdered on sandpaper when sanding a coat of finish. May indicate the finish is not sufficiently cured for sanding. Corns on the paper surface will mar the surface being sanded and the paper should be replaced.
Coverage	Referring to the ability of a coating to cover a surface. Often referred to as spread rate calculated in either square feet per gallon or square meters per liter.
Cracking	Splitting of a coating film as a result of aging, formation of internal stresses or deformation of substrates.
Crackle Finish	Intentional splitting of a coating film to replicate an aged look.
Craters/Cratering	Small, shallow, bowl-shaped depressions in a coating film. Viewed under magnification, these depressions frequently have drops, particles, or bands of material at their centers and raised circular edges. Some common causes of cratering are: oil particles/droplets from air lines, and substrate contamination such as silicone from furniture polish or machinery lubricants. Also known as fisheye.
Crawling	When a coating applied tends to flow away from areas leaving them uncoated. This is usually caused by grease or oil contamination of the surface to be coated.
Crazing	Formation of surface fissures (similar to cracking ) that change the properties of the film. However, it is much less severe than cracking and does not penetrate to the underlaying surface.
Cross Spraying	Spraying the first pass in one direction and the second at a right angle to the first, providing more even film distribution. Also known as box coating or cross hatching.
Crosslinking	The setting up of chemical links between molecular chains to form a three dimensional network of connected molecules.
Crosslinking agent	Catalytic or reactive agent which when added to resin causes crosslinking of chains (aka, curing agent, hardener).
Cure	Process by which a coating is converted from the liquid to the solid state by changes in the properties of the resin by chemical reaction (crosslinking/conversion).
Curing Agent	A hardener or activator added to a synthetic resin to develop the proper film forming properties.
Curtains	Long horizontal runs in a coating film that occur on vertical surfaces when a coating is applied too heavily. Sagging on a large scale.

[D]

TERM	DEFINITION
De-Gloss	The removal of the shine on a surface either by sanding or chemical de-glossers. (see scuff sanding)
Deionized Water	Water which has been purified to remove mineral salts.
Delamination	The separation between layers of coats or substrate due to poor adhesion.
Denatured alcohol	Ethyl alcohol with a small percentage of a poison added. Used as a solvent for shellac and some dyes.
Density	Mass per unit volume, usually expressed as grams per milliliter or pounds per gallon.
Dew Point	The temperature of a surface, at a given ambient temperature and relative humidity, at which condensation of moisture will occur.
DFT	Dry film thickness.
Diluent	Portion of the volatile components of a coating which is not a true solvent. Has minimal effect on the viscosity and reduces the solids content in applied coating formulations.
Dispersion	The suspension of tiny particles, usually pigments, in a liquid, usually resin.
Distilled Water	Water which has been purified by vaporizing the liquid and collecting the vapor which is then condensed back to a liquid having, in the process, removed the contaminants.
Distressing	Fly speck spotting, sand throughs, dents, scrapes, gouges, cracks, holes, and other age marks in the finished surface or on the substrate.
Drier	Chemical agent which promotes oxidation and drying of a coating. Mainly used in oil based coatings, printing inks and varnishes. Driers are usually metallic compositions and are available in both solid and liquid forms. Different groups of driers are available: primary driers (active driers), secondary driers (auxiliary driers), and combination driers.
Dry Fall	A coating which is designed to dry rapidly so that the overspray can be easily removed from the surfaces below. The coating is dry by the time it falls to the floor.
Dry Hard	The elapsed time at which a coating has reached its optimum hardness. Although finishes like shellac, lacquer, and waterborne don't cure/crosslink, they do retain slvents in the film for long periods and continue to shrink as the solvents slowly evaporate. This slow evaporation and shrinkage is the reason behind the recommendation to wait up to a month before rubbing these finishes to a high gloss. Otherwise, the finish may continue to shrink and the pores in the wood will re-appear in the surface of the finish as dimples.
Dry Spray	Formation of a powdery surface while spraying. This is 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 surface. The fine aerosol formed looses its solvent and is deposited in an almost dry form on the surface.
Drying Oil	An oil having the property of hardening by oxidation to a tough film when exposed to air in the form of a thin film.
Drying time	The interval between the application of a coating and when it is ready for service.
Dry Spray	Overspray or bounce back producing a sandy finish due to the sprayed particles having partially dried before reaching the surface.
Dry Time	Time allotted for an applied coating film to reach a set stage of cure or hardness.
Dry to Handle	The degree of cure at which a film will resist deformation due to handling.
Dry to Recoat	The time required for a cured film to dry prior to the application of a second coat without adverse impact.
Dry to Tack Free	A stage at which a coating film will form a skin to which dust will not adhere.
Dry to Touch	The state of dry at which a coating film will not transfer onto an item touched lightly against it.
Dulling	A loss of gloss or sheen.
Durability	The degree to which a coating can withstand the destructive effects of the environment to which it is exposed including the ability to withstand scrubbing, abrasion, etc. Not directly related to hardness.
Dust Nibs	A surface defect in a dried coating caused by small particles settling on the surface of the finish as it was drying, before a film had formed on the surface. Repaired by sanding level and recoating or rubbing out.
Dye	A coloring material that dissolves completely in a system that is very transparent.

[E]

TERM	DEFINITION
Effervescence	An effect in the film caused by rapid solvent release. This "boiling" of solvent causes a pinholed or cratered appearance reducing gloss.
Eggshell	A low-luster paint sheen between flat and satin.
Elastic	The ability of a substance to return to its original shape or volume after a distorting force on the substance has been removed.
Electrostatic Spray	System of applying a coating in which the coating droplets from an air, air-assisted airless, or airless spray gun are given an electrical surface charge. These electrical charged droplets are attracted to an electrically grounded workpiece.
Emulsion	A two phase liquid system in which small droplets of one liquid are immiscible in and are dispersed uniformly throughout a second continuous liquid phase.
Enamel	Technically, an enamel is a colored varnish, or high gloss paint. Generally, the term is used for high quality, dirt-resistant paints for interior use that may have a sheen level from satin to glossy. These coatings are used for more demanding applications as in kitchens, bathrooms, etc.
Epoxy	A synthetic resin, derived from petroleum products, that can be cured by a catalyst or used to upgrade other synthetic resins to form a harder, more chemical resistant film.
Ester	Compounds formed by the reaction of alcohols and organic acids.
Evaporative Coating	Cure by solvent evaporation alone and don't undergo a chemical conversion of the binder/resins during curing. Evaporative finishes can, and usually do, undergo intermolecular mechanical changes as they cure. Lacquer, shellac, and most water-borne coatings are example of the evaporative type. Molecules in the dry film are held together by intermolecular forces that are different than the chemical bonds formed as part of a reaction, as in the case of conversion coatings. However, in many cases, binder resins present in evaporative coatings still undergo a permanent chemical conversion after most of the solvent in the coating has evaporated. See Dry Hard.
Exempt solvent	Solvent which is not subject to air pollution legislation. Acetone for example.
Extender	A low hiding, inexpensive pigment that fills out and extends the high-hiding pigment's capabilities, provides bulk to the paint, and can positively or negatively have an impact on many properties. Some common extenders are clays, calcium carbonate, and silica.
External Atomization	Using air to break up a coating material after it has exited the spray gun nozzle.

[F]

TERM	DEFINITION
Fading	The loss of color most commonly due to exposure to sunlight (UV).
Fan Pattern	The geometry of a spray pattern.
Fast to Light	A color which is not significantly affected by exposure to sunlight.
Faux Finishing	The technique of applying finishes to a surface to make it look like another material. Faux finishes can look like leather, stone, marble, etc.
Feather Edge	Reduced film thickness at the edge of a dry film finish in order to produce a smooth, continuous appearance.
Filler	A compound used to extend or bulk a coating to provide extra body or hiding power.
Film	A layer of coating or paint.
Film Build	The dry film thickness characteristics of a coat.
Film forming process	Formation by drying of a solid and coherent polymer-matrix film from a fluid coating applied to a substrate. Drying can be physical drying (for coatings based on thermoplastic binders), chemical drying (for coatings based on reactive binders), or both.
Film Integrity	The continuity of a coating free of defects.
Film Thickness Gauge	A device for measuring wet or dry film thickness.
Fineness of Grind	The degree of dispersion of particles within a liquid.
Fingering	A broken spray pattern delivering heavier coating to one area than another.
Fire Resistant Finish	See "Intumescent Coating."
Fish Eye	Circular voids, pock marks, craters, or separation in the coating. Fish-eyes can be caused by oily spots or silicone particles and/or by air-borne droplets that are deposited on the surface being finished. Not uncommon in refinishing when the piece was polished with a product containing silicone.
Fish Eye Eliminator	An additive (e.g., "Smoothie") that contains silicone. Eliminates the surface tension difference on a contaminated substrate allowing the finish to flow level.
Flammable	Any substance easily ignited in the presence of a flame; any liquid having a flash point below 100F (38.8C).
Flash Point	The lowest temperature of a liquid at which sufficient vapor is provided to form an ignitable mixture when mixed with air.
Flash or Flash-Off	The point at which a sprayed coating stops flowing or leveling. Premature flash causes orange-peel when the atomized droplets do not flow into a completely flat and even film.
Flash-Off Control Solvent	An additive that extends the wet time or "flash" of a sprayed or brushed coating. See "retarder."
Flash-Off Time	The time needed to allow the solvents to evaporate and the sprayed finish to form a surface film. The time which must be allowed after the application of a film finish before baking/forced drying in order that the initial solvents are released, which prevents bubbling.
Flash Point	The temperature at which a material will ignite when exposed to a source of ignition.
Flat	A coating that has little or no sheen.
Flexibility	The degree at which a coating is able to conform to movement or deformation of its supporting surface without cracking or flaking.
Floating/Flooding	Coating defect where a concentration of one of the ingredients of the pigment portion of a coating sits at its surface (floating) or in patches inside the coating film (flooding), leading to a color change and non-uniformity.
Flocculation	Reversible formation of clusters of particles in emulsions and suspensions. In paints, flocculation of polymer particles may occur in emulsion (latex) paints, and flocculation of pigment particles may take place in any paint because of a deficiency of emulsifier and dispersants or changes in conditions of state (pH, solvent, etc.). Flocculation may cause loss of tinting strength, hiding power, or change flow behavior.
Flood	The act of applying a coating very heavily to the substrate.
Flow	The degree to which a wet coating film can level out after application so as to eliminate brush marks and produce a smooth, uniform finish.
Fluid Tip	The orifice in a spray gun to which the needle is seated (aka, nozzle).
Fluorescent	A class of pigments which, when exposed to visible light, emit light of a different wave length producing a bright appearance.
Force Drying	The acceleration of drying by increasing the ambient temperature.
Foreign Thinner	Any thinner not recommended on the label or in published literature of the manufacturer, which can affect the coatings performance.
French Polish	A shellac base coating which is applied by manually "padding" it onto the surface.
Fungicide	A substance poisonous to fungi which retards or kills mold and mildew growth.

[G]

TERM	DEFINITION
Gelled	A coating which has thickened to a jelly like consistency making it unusable.
Glaze	A type of wiping stain applied over a sealed or partially sealed (washcoat) surface and then sealed in with the topcoats. Glazing stains are NOT intended for use on bare wood though thick gel stains can be used as a glazing stain. Glazes are used to highlight shapes and design elements, add a layer of color in the finish, and create faux finishes. There are some spray only, dry on contact glazes available that cannot be manipulated other than selectively removing portions of the glaze to control color intensity. These glazes are used to accentuate design features and/or create an aged/antiqued look.
Gloss	The sheen or ability to reflect light. Flat finishes have no gloss. High gloss finishes are very shiny. Also known as sheen.
Gloss Retention	The ability to retain the original sheen during weathering.
Glycol Ether	A group of relatively slow evaporating, strong solvents.
Grain	The direction, size, arrangement or appearance of the fibers in wood.
Grain Raising	The swelling and raising of wood fibers caused by absorption of water.
Grit	A measure of the size of abrasive particles used in the manufacturing of sandpaper. Grit can also be measured as the number of particles in an square inch of sandpaper surface.

[H]

TERM	DEFINITION
Hard dry	See "Dry Hard"
Hardener	An activator curing agent, catalyst or cross linking agent. Substance or mixture of substances added to a resin to promote or control the curing reaction by taking part in it. Also known as crosslinking agent or curing agent.
Hardness	The degree to which a material will withstand pressure without deformation or scratching. Hardness is not an indicator of durability, but harder finishes can be rubbed out more easily. Finishes can be tested for hardness using the Pencil Hardness Test.
Hiding (Hiding Power)	The ability of paint or exterior stain to obscure the surface over which it has been applied. Hiding power is provided by the paint’s pigment (quality pigments cost more and work better), and is affected by how thickly the paint is applied and how well brush marks flow out.
High Build	A term referring to a coating/finish which can produce a thick film in a single coat.
Holiday	Any discontinuity, bare or thin spot when applying topcoats (you missed a spot!).
Hue	The basis of color (e.g., whether a color is red, green, etc.). Lighter or darker variations are still the same hue. Thus, a light red and a deep red are the same hue. See tint and shade.
Hybrid Coating	A coating which exhibits the properties of both an evaporative and a conversion finish. Waterborne coatings and catalyzed lacquers are two examples. Even though solvent evaporation is the primary film-forming mechanism and what creates a "dry" film, secondary conversion reactions may occur during the "curing" of the dry film - this adds toughness and chemical resistance.
Hydrocarbon	Extracts from petroleum such as gasoline, lubricating oils, solvents, etc.
Hydrophilic	A substance which absorbs or has an affinity for water.
Hydrophobic	A substance which does not absorb or exhibit an affinity for water.

[I]

TERM	DEFINITION
Immersion	Referring to an environment which is continuously submerged in a liquid, often water.
Impact Resistance	The ability to resist deformation or cracking due to a forceful blow.
Incompatibility	Unsuitable for use together because of undesirable chemical or physical effects. Often used in reference to coatings and/or stains which are not capable of being mixed with one another (e.g., shellac that contains wax and polyurethane or waterborne finishes).
Induction Time	The period of time between mixing of two component products and the moment they can be used. For example, when mixing dye with a waterborne finish, you should wait an hour before using it to give the dye time to incorporate into the finish. Some catalyzed finishes have a waiting period before use once the catalyst is added.
Inert Pigment	A non-reactive pigment, filler or extender.
Inhibitive Pigment	A pigment which assists in the prevention of the corrosion process.
Inorganic	The designation of compounds that do not contain carbon.
Inorganic pigment	Natural or synthetic pigment such as metallic oxide, sulfide, and other salts. Possesses outstanding heat- and light-stability, weather resistance, and migration resistance.
Inorganic Zinc	A coating based on a silicate resin and pigmented with metallic zinc which has excellent resistance to organic solvents and general weathering.
Insoluble	The inability to be dissolved.
Intercoat Adhesion	The adhesion between successive coats of finish.
Intercoat Contamination	The presence of foreign matter such as dust or dirt between successive coats of finish.
Internal Mix	A spray gun in which the fluid and air are combined before leaving the gun.
Intumescent Coating	A fire retardant coating which, when heated, produces nonflammable gasses which are trapped by the film, converting it to a foam, thereby insulating the substrate.
Iron Oxide	An oxide of iron. The natural occurring state of steel.
Isopropyl Alcohol	A volatile, flammable liquid used as a solvent commonly known as rubbing alcohol.

[J]

[K]

TERM	DEFINITION
Ketone	An organic compound with a carbonyl group attached to two carbon atoms. Usually indicates a strong, fast evaporating solvent.
Kick-out	Precipitation of a dissolved binder from a solution as a result of solvent incompatibility. Can be caused by improper mixing or adding the flow control component to quickly to the mixed system.

[L]

TERM	DEFINITION
Lacquer	A coating comprised of a synthetic film forming material which is dissolved in organic solvents and dries by solvent evaporation. The film remains susceptible to attack by the same or similar solvents. Typical lacquers include those based on nitrocellulose, other cellulose derivatives, vinyl resins, acrylic resins, etc.. See "Evaporative Coating."
Lacquer Thinner	A blend of solvents used to reduce the viscosity of lacquer and/or eliminate blushing (see "Retarder").
Lap Marks	Marks left when a coat of dye, stain, or finish, including paint, extends over an adjacent coat that has been allowed to dry too long.
Latex Paint	Water-based paint made with a synthetic binder such as acrylic, vinyl-acrylic, or styrene acrylic latex. (see Polymer)
Lead-Free	Contains, by weight, less than 0.5% lead for industrial products and less than 0.6% lead in consumer products.
Leafing	Ability of flat pigments to align themselves more or less parallel with the coated surface. This property produces a reflective appearance of the film.
Level/Leveling	Leveling leads to uniformity of the surface of the coating. Leveling measures the ability of a wet coating to flow out to a smooth film after application so as to avoid leaving any surface irregularities which have been produced by the mechanical process of applying the film, such as brush marks, roller marks, craters or orange peel from spraying. Also used to describe the process of sanding the surface of a finish flat prior to rubbing out.
Leveling agent	Additive which is able to reduce the surface tension under dynamic and static conditions, to obtain an optimal wetting and leveling effect, and to improve the surface flow of the coating. Poor surface flow can induce coating defects such as orange-peel, craters, brush marks, etc..
Lifting	Softening and raising or wrinkling of a previous coat by the application of an additional coat; often caused by coatings containing strong solvents. This is usually caused by applying strong solvented coating over a curing type coating (curing type coatings include catalyzed lacquer, urethane lacquer, polyurethane and enamels.)
Lightfast	A color/colorant which is not significantly affected by exposure to sunlight.
Light Reflectance Value (LRV)	The amount of light reflected from a coatinged surface. Usually reported as a percentage.
Liming	Application of a white or off-white pigmented stain over sealed wood leaving the pores colored. Colored wax works as well and is reversible.

[M]

TERM	DEFINITION
Metallic pigment	Pigment consisting of thin opaque aluminum flakes (made by ball milling either a disintegrated aluminum foil or a rough metal powder and then polishing to obtain a flat, brilliant surface on each particle) or copper alloy flakes (known as bronze pigments). Produces silvery and other metal-like effects.
Metamerism	A phenomenon exhibited by a pair of colors which match under one light, but not another. An example can include colors that match indoors in incandescent light and not outdoors in natural sunlight.
Methyl Ethyl Ketone (MEK)	A low boiling, highly volatile flammable solvent with extremely good solubility for most vinyls, urethanes and other coatings.
Methyl Isobutyl Ketone (MIBK)	A medium boiling solvent commonly used in vinyls.
Methylene Chloride (MC)	A chlorinated hydrocarbon (halogenated solvent). MC is one of the oldest and most common solvents used in paint and varnish strippers. It's very effective at removing most finishes/paints, including those that crosslink during the curing process. Although MC is non-flammable it is toxic and a suspected carcinogen. It metabolizes in the blood to form carbon monoxide. This causes the heart to pump harder and can trigger heart attacks in people with existing heart conditions. For this reason, if you have a heart condition, avoid using a coating remover with MC as a listed ingredient. Alkali fortified MC is often used in "marine grade" finish removers and are available at most marine supply store. Alkali fortified MC strippers are effective on tougher coatings such as epoxy and polyester. They are more expensive and hazardous to work with so additional care should be taken when selecting and using these stripping agents.
Micron	A micrometer or one millionth of a meter (.000001 meters).
Mil	One one-thousandth of an inch (.001 inches). Commonly used to denote coating thickness.
Mildew	A superficial growth of living organic matter produced by fungi in the presence of moisture; results in discoloration and decomposition of the surface.
Mildew Resistance	The ability of a finish or paint to resist mildew growth on its surface.
Mildewcide	Chemical agent that aids in the inhibition of mildew growth. Especially helpful in humid climates.
Mineral Spirits	A refined petroleum distillate having a low aromatic hydrocarbon content and low solubility; suitable for thinning of alkyd coatings. Paint thinner contains mineral spirits and often a blend of other petroleum distillates.
Minimum film forming temperature (MFFT)	Temperature below which the effective coalescence of emulsion particles in a waterborne coating cannot occur. Defects, such as poor water resistance, high permeability, color and gloss variations, poor washability, etc., can result in waterborne coatings cured below the MFFT.
Miscible	Capable of mixing or blending uniformly.
Mist Coat	A thin tack coat usually applied to fill porous surfaces, seal in contamination, or seal the wood and reduce grain raise.
Moisture Resistance	The ability of a coating to resist swelling, blistering, other damage caused by moisture.
Monomer	Low molecular weight molecules capable of combining with a ber of like or unlike molecules to form a polymer.
Mottled	Spots of different tones and colors next to each other resulting in a blotchy effect.
MSDS	Material Safety Data Sheet. An informational document provided the manufacturer regarding the safety and handling procedures and cautions for materials used in the workplace.
Mudcraking	A paint film defect characterized by a broken network of cracks in the film.

[N]

TERM	DEFINITION
Naphtha	A fast evaporating petroleum distillate solvent used to thin oil-based coatings and to clean up.
Neutral	A liquid which is neither acid nor alkali such as water; pH7.
Neutral-Tone	Color range for faux finishing that consists of off-whites, beiges, or grays that provide a base color.
Nitrocellulose	The primary resin material used in making lacquer.
Non-Drying Oil	An oil which undergoes little or no oxidation when exposed to air and therefor has no film forming properties (e.g., mineral oil)
Non-flammable	A compound which does not burn in the presence of a flame.
Non-volatile	The solid portion of a coating consisting of pigment and binder. It's the portion of the coating left on the surface after it's dry (solids content).

[O]

TERM	DEFINITION
Oil-base	Generally, finishing products (e.g., stains, clear coats, and paints) made with a drying oil, such as linseed, soya, or tung oil as the vehicle and binder, and mineral spirits/paint thinner or naphtha as the thinning agent. Also used to describe a class of stains based on fast drying alkyd binders that are reducible with mineral spirits or naphtha.
Oil Length	The ratio of oil to resin expressed as a percentage of oil by weight in the resin. Used to determine the physical properties of a resin/finish.
Opacity	The ability of a paint film to obliterate or hide the color of the surface to which it is applied. A paint with a high opacity will hide the substrate well. The opposite of transparent.
Opaque	Finishes that obscure the surface being coated. Includes a wide range of brushable and sprayable paints and some exterior stains.
Open Time	The length of time a coating remains wet enough to allow for brushing-in without lapping.
Orange Peel	Dimpled, bumpy, or wavy surface of a film similar in appearance to the skin of an orange. Usually caused by spraying in high heat, draft or a material that is too thick or heavy in viscosity resulting in poor leveling. A common defect in both spray and roll applied coatings. For some coating appliances, an orange peel effect may be desirable.
Organic	Designation of any chemical compound containing carbon.
Organic Zinc	A zinc rich coating utilizing an organic resin such as an epoxy.
Osmosis	The diffusion of liquid through a paint film or other such membrane.
Overspray	Sprayed coating that is dry when it hits the surface resulting in dusty, granular adhering particles, reducing gloss and presenting a poor appearance.
Oxidation	A chemical reaction with oxygen. The formation of an oxide; the curing mechanisms for alkyds.
Oxidative Polymerization	Mechanism of drying unsaturated binders (cooked oils, alkyds etc.) in relatively thin films in the presence of atmospheric oxygen, initiated and catalyzed by driers.

[P]

TERM	DEFINITION
Paint	(Verb) To apply a thin layer of a pigmented, opaque coating to a substrate by brush, roller, spray or other suitable method. (Noun) A opaque pigmented finish designed for application to a substrate, in a thin layer, which is then converted to an solid film. Paint is designed to protect and/or decorate the surface it is applied to. Generally a paint contains binders (resins), solvents, pigments, and additives. Paints may be pigmented oil-base coatings, waterborne coatings, lacquer coatings, catalyzed coatings, etc..
Pass	The motion of operating a spray gun in one direction only.
Paste	The product of a dispersion process. It is usually very high viscosity and requires dilution prior to application; a concentrated pigment dispersion used for shading.
Pattern	Shape of stream of material coming from a spray gun. Also the sequence of spraying various items to maintain a wet edge and avoid overspray.
Peeling	A film of coating lifting from the surface due to poor adhesion.
Penetrating Finish	A coating that is absorbed into the substrate rather than forming a film on its surface. Drying oils are penetrating finishes.
Percent Solids	Percentage mass of non-liquid components in coatings.
Permeability	The degree to which a membrane or coating film will allow the passage or penetration of a liquid or gas.
pH	A measure of acidity and alkalinity; pH 1-7 is acid and pH 7-14 is alkali.
Phenolic Resin	Thermosetting synthetic resin produced by the condensation of phenol with an aldehyde (e.g., formaldehyde). Provides very good heat and water resistance.
Photoinitiator	Additive which, when exposed to a specific wavelength of energy, forms a reactive species which starts the chain reaction to cause polymer formation. Most commercial photo-iniators for radical curing reactions contain benzoil groups, which are mainly responsible for the absorption of energy from light.
Pickling	Application of a white, off-white, or pastel pigmented stain on bare wood leaving as little or as much color as desired. Thinned paints work very well.
Pigment	A finely ground natural or synthetic, insoluble particle adding color and opacity or corrosion inhibition to a coating film.
Pigment/Binder	A ratio of total pigment to binder solids in coatings.
Pigment Volume Concentration (PVC)	The percent by volume occupied by pigment in the dried film of paint generally expressed as a percentage.
Pinholing	A film defect characterized by small, pore-like flaws in a coating which extend entirely through the film.
Plasticizer	An agent added to the resin to aid in flexibility. Compounding material used to enhance the deformability of a paint, varnish or lacquer. A plasticizer is soluble in the polymer and decreases the glass transition temperature (Tg) value, softens and adds flexibility to the product.
Polyester Resin	A group of synthetic resins which contain repeating ester groups. A special type of modified alkyd resin. Polyester finishes are among the most durable.
Polymer	Large organic molecule formed by combining many smaller molecules (monomers) in a regular pattern. Plastic-like material produced from chemical "monomers" which in turn have been produced from alcohols and petrochemicals. Certain polymers are used in waterborne finishes and paints. The binder’s polymer particles are small and carried in water. The binder polymer particles and water mixture is known as an emulsion or as “latex”.
Polymerization	A chemical reaction in which two or more small molecules combine to form large molecules containing repeated structural units.
Polyurethane	An exceptionally hard, wear resistant coating polymer made by the reaction of polyols with a multi-functional isocyanate. Provides toughness, flexibility, weather resistance, chemical resistance, and abrasion resistance to the coating film. Commonly used to make topcoats.
Polyvinyl Chloride (PVC)	A hard tough plastic solid used for plastics and coatings, commonly known as vinyl.
Porosity	The presence of numerous minute voids in a cured material.
Post-cure reaction	Crosslinking reaction which occurs in cured coating due to the presence of an excess of a hardener. Can cause coating defects such as internal stress, decreasing adhesion durability and flexibility.
Pot Life	The length of time a coating material is useful after its original package is opened or a catalyst or other curing agent is added. As mixed material reacts in the pot, the viscosity always increases.
Potable Water	Water fit for human consumption; as in drinking water.
Powder coating	100% solid coating generally applied by an electrostatic process as a fine, dry powder to the surface and then heated above its melting point so the powder particles flow together or cure.
Practical Coverage	The spreading rate of a coating calculated at the recommended dry film thickness and assuming 15% material loss.
Precipitate	An insoluble substance separated from solution by the action of some reagent added to the solution, or of some force, such as heat or cold. The precipitate may fall to the bottom, may be diffused through the solution, or may float at or near the surface.
Primary Colors	Colors that cannot be produced by mixing any two other colors. They are red, yellow, and blue.
Primer	The first complete coat of paint applied in a painting system. Many primers are designed to provide adequate adhesion between the surface and subsequent topcoats. Most primers contain some pigment, some lend uniformity to the topcoat, some inhibit corrosion or the substrate, and some stop the discoloration of the topcoat.
Primer-Sealer	A priming system that minimizes or prevents the penetration of the topcoat into the substrate.
Print Resistance	The ability of a coating to avoid pressed-in markings from an object placed on it.
P.V.A. (Polyvinyl Acetate)	A binder most widely used in interior latex wall paints.
Pyrometer	An instrument used to measure the temperature of a surface.

[Q]

TERM	DEFINITION
QUV	An accelerated testing device designed to evaluate the fading properties of a coating by exposure to high intensity, ultraviolet light.

[R]

TERM	DEFINITION
Re-coat Time	Interval required between the application of successive coats of finish. This time period is usually listed on the label. The actual time may vary from the manufacturer's guideline in cases where the temperature is well above or below 70 degrees and the humidity is higher than 50%.
Reduce	To add solvent in order to thin a material to a workable thickness (viscosity).
Reducer	Commonly known as thinner.
Reflectance	The ratio of the light that radiates onto a surface to the amount that is reflected back.
Related Colors	Two colors that are next to each other on the color wheel.
Relative Humidity	The ratio, expressed as a percent, of the quantity of water vapor actually present in the air to the greatest amount possible at a given temperature.
Resin	Solid, semi-solid or pseudo-solid organic material which has an indefinite and often high molecular weight. Exhibits a tendency to flow when subject to stress. Can be natural or synthetic. Used as the binder and/or film forming agent in finishing products.
Retarder	Solvent added to a coating to slow down its evaporation rate.
Rheology	The science characterizing fluid deformation or flow.
Roller	A cylinder covered with lamb's wood, felt, foamed plastics or other materials used for applying paint.
Runs	Sagging and curtaining of a coating or paint film, usually caused by improper thinning, excessive film build or poor application techniques.

[S]

TERM	DEFINITION
Sag/Sagging	Narrow (or wide curtain-like) downward movement of a film finish; may be caused by the application of too much coating, the collection of excess quantities of finish at irregularities in the surface (cracks, holes, etc.), or excessive material continuing to flow after the surrounding surface has set. Also referred to as runs or tears.
Sag Resistance	The ability of a coating to be applied at proper film thicknesses without sagging.
Salt Atmosphere	A moist, heavily ladened air with a high chloride concentration; used as a test for accelerated corrosion evaluations and also present near sea coast areas.
Salt Fog Test	A cabinet designed to accelerate the corrosion process in evaluating coatings; combines 100% humidity with a 5% salt concentration at 100F in an enclosed cabinet.
Sandability	Ease of sanding of a coating.
Sanding Sealer	Especially hard first coat that can seal and fill, but will not obscure, the grain of the wood. Formulated to give better filling and sandability than the topcoat products. The surface is then sanded before subsequent coats are applied.
Satin Finish	Sheen of coating with a 60 degree gloss reading between 10 and 40.
Saponification	The alkaline hydrolysis of fats whereby a soap is formed; typical reaction between alkyds and galvanized metals resulting in peeling.
Scratch resistance	Ability of a coating surface to resist to damage caused by sharp and hard objects. Influenced by the hardness, the coefficient of friction and the thickness of the film.
Scrub resistance	Ability of a coating surface to resist to damage caused by rough objects in the presence of an active medium (water or organic liquid, abrasive material).
Scrubbability	The ability of a coating to resist wearing away or changing its original appearance when rubbed with a brush, sponge, or cloth and an abrasive soap.
Scuff Sand	To lightly sand in order to remove the shine or roughness of a surface prior to recoating.
Secondary Colors	Colors formed by mixing together two primary colors. They are orange, green, and purple.
Sealer	A coating used on absorbent surfaces prior to topcoats.
Seeding	Formation of small agglomerates or gel particles (seeds) in a coating. Caused by resin insolubility, aggregation of pigment particles, or a combination of both factors.
Semi-gloss	A finish with a sheen level between high gloss and satin (or eggshell).
Settling	The sinking of pigments, extenders, flatteners or other solid matter in a coating/paint, on standing in a container, with a consequent accumulation on the bottom of the can.
Shade	A shade is created when black is added to a color. It is a darker variant of a color.
Shading/Shading Stain	A shading stain is a dye and/or pigmented colorant added to a thinned clear film forming finish used to add coloring in specific areas on a piece being finish. Shading can be used to accentuate a design feature, increase the color intensity, alter the existing color, or to blend and uniform area(s) on the piece.
Shelf Life	Period of time during which a finishing product stored according to the manufacturer's instructions (packaging, temperature, humidity) retains its expected properties.
Shellac	Alcohol-soluble resin derived from lac available in a variety of grades/colors. Lac is a substance secreted by insects on tree branches, mainly in India. Used as a sealer for sealing knots, a clear finish, and in "alcohol-based" primers. The thinner is denatured alcohol.
Siccative	Catalyst used for drying according to the oxidative polymerization mechanism (aka, drier).
Silicone Resins	Resins based on silicone instead of carbon, generally used for their outstanding heat resistance and water repellency.
Silking	Fine parallel irregularities in a paint film that give the appearance of silk. This defect usually is a special case of floating and flocculation in coating finishes.
Skinning	The formation of a solid membrane on the top of a liquid, caused by partial curing or drying of the coating during storage.
Slip agent	Additive which reduces the friction coefficient and thereby improve slip characteristics of coating films. Various waxes, silicones or modified polyesters can be used to increase surface slip.
Softwood	The group of trees (fir, pine, spruce, hemlock) characterized by its needles and being (for the most part) evergreen. The term does not refer to the hardness of the wood, only its classification.
Solids Content	Non-volatile matter in the composition of a coating. The ingredients in a coating that, after drying, constitute the dry film. Solids are composed mostly of binder and pigment (in paints).
Solids by volume	Percentage of the total volume occupied by nonvolatile compounds.
Solids by weight	Percentage of the total weight occupied by nonvolatile compounds.
Soluble	The ability of a material to be dissolved in a liquid For example, sugar is soluble in water.
Solvent	A solvent is a liquid that dissolves another substance to form a solution (a homogeneous mixture). The material dissolved in the solvent is called the solute. Together, the solvent and solute comprise the solution. The solvent is the component in the solution that is present in the largest amount or is the one that determines the state of matter (i.e. solid, liquid, gas) of the solution. Solvents are usually, but not always, liquids. They can also be gases or solids. Solvents can dissolve solids, liquids or gases. Water is a solvent. Every day, people dissolve soap in water creating a soap solution. Different classes of solvents dissolve different substances more readily. For example, some oils readily dissolve in mineral spirits, but not in water.
Solvent Entrapment	The encapsulation of solvent within a cured coating film due to improper drying conditions; results in a non-continuous film.
Spar Varnish	Exterior varnish with good water resistance and the capability to resist weathering. Named for its original use on the spars of ships.
Specification	A set of instructions detailing the plan for coating of a project; a list of criteria for a coating.
Splotch	See "Blotch."
Spray Head	The combination of needle, tip and air cap.
Spray Pattern	The configuration of coating sprayed on the surface.
Spread Rate	Coverage, usually at the specified dry film thickness.
Stain	A partly transparent coating that can color wood without obscuring the grain and/or the texture. May also refer to materials that soil the surface.
Stain Bleed-through	When tannin found in certain types of wood (such as oak, cedar, or redwood) migrates through the coating, causing discoloration. Also, discoloration from a contaminant on the substrate.
Stain Resistance	The ability of a coating to resist soiling.
Stripping	Removing old paint, varnish, etc., by using a chemical paint remover, sandpaper, heat gun, or scraping tools.
Strong Solvent	Any solvent capable of dissolving large quantities of a specified subject.
Substrate