Automotive Paint Terms

A

ABRASION RESISTANCE: Resistance to being worn away by rubbing or by friction; related more to toughness than to hardness. A necessary quality for automotive finish durability.

ABRASIVE: Used for wearing away a surface by rubbing. Examples are sandpaper, steel wool, compound, clay, scotch-brite, etc.

ACRYLIC: Synthetic resin used in a latex coating with good gloss and color retention.

ADHESION: The ability of a coating to stick to a surface.

AEROSOL: A product feature that uses compressed gas to spray the product from its container.

ALKALI: A substance such as lye, soda, or lime that can be highly destructive to paint films.

ALKYD: Synthetic resin modified with oil. Common in the early automotive enamels in the ‘60s, offered good adhesion to a clean surface, and good gloss, color retention, and flexibility, but tended to chalk out sooner and offer a shorter life that either the pervious lacquers, or the later acrylic enamels. Slow-drying.

ANTI-CORROSIVE PAINT: Metal paint designed to inhibit corrosion. Applied directly to metal.

ACCELERATOR: A chemical that can be added to some paints to speed the curing time.

ACRYLIC ENAMEL: Chemically enhanced enamel formulas are the mainstay of modern refinishing products. Many acrylic enamels recommend a catalyst, while others require it,  to induce chemical reactions that produce a paint film of remarkable durability, chemical resistance, and gloss. Acrylic enamels can be polished like lacquer to a mirror finish.

B

BENZENE: Powerful but highly toxic and flammable solvent, usually restricted to spray application.

BENZINE: Often used as a lacquer dilutent. Highly volatile and a fire hazard in shipping and storing.

BINDER: Film-forming ingredient in paint that binds the pigment particles together.

BLEEDING: Undercoat staining through the top coat.

BLISTERING: The formation of bubbles or pimples on the painted surface caused by moisture or other contamination, by painting before the previous coat has dried thoroughly, or by excessive heat.

BLOCKING: Sanding primer or topcoats by hand with a flat backing surface such as a long-board or rubber sanding block.

BLUSHING: A gloss film turning flat or a clear lacquer turning white, usually caused by moisture

BUILD: Thickness or depth of paint film.

C

CATALYST: An ingredient that speeds up a chemical reaction; sometimes used in two-component paint systems. Sometimes referred to as activators, catalysts contain chemicals that interact with the resins of the base paint allowing it to cure more rapidly.

CHALKING: The formation of a loose powder on the surface of a paint after exposure to the elements.

CHECKING: A kind of paint failure in which many small cracks appear in the surface of the paint.

CLEAR COATING: A transparent protective and/or decorative film.

COHESION: Attraction of molecules within a coating [how it holds together).

COLORANT: Concentrated color that can be added to paints to make specific colors.

COVERAGE: The area over which a given amount of Paint will spread and hide the previous surface. (Usually expressed in square feet per gallon).

CRAZING: Small, interlacing cracks on surface of finish.

CURING: Final conversion or drying of a coating material.

D

DRIER: A paint ingredient that aids the drying or hardening of the film.

DILUENT: Another term for solvents used to thin paint.

DRY DUST FREE: That stage of drying when particles of dust that settle upon the surface do not stick to the paint film.

DRY TACK FREE: That stage of drying when the paint no longer feels sticky, or tacky when lightly touched.

DRY TO HANDLE: That stage of drying when a paint film has hardened sufficiently so the object or surface painted may be used without marring.

DRY TO RECOAT: That stage of drying when the next coat can be applied.

DRY TO SAND: That stage of drying when a paint film can be sanded without the sandpaper sticking or clogging
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DURABILITY: The ability of paint to last or hold up well against destructive agents such as weather, sunlight, detergents, air pollution, abrasion, or marring.

E

ENAMEL: Broad classification Paints that dry to a hard finish. Enamel is a general term covering a wide range of paint, including hardware store spray cans. Single-stage alkyd automotive refinish enamels have been replaced by acrylic enamel which generally gives you the option of using a hardener or catalyst. Urethane enamels are even more durable and require a catalyst.

EPOXY: Clear finish having excellent adhesion qualities; extremely abrasion and chemical resistant. Epoxies are alcohol proof and very water resistant.

ETCH: Surface Preparation by chemical means to improve the adhesion of coatings.

ETCHING PRIMER: A primer with ingredients that etch into bare metal for better adhesion, also referred to as self-etching primer. Primarily used to prep bare metal.

F

FADING: The loss of color due to exposure to light, heat, or weathering.

FEATHER SANDING: Tapering the edge of dried paint film with sandpaper.

FILLER: Any material designed to fill surface flaws, from polyester body filler, spot putties and glazes, to primer surfacers.

FILM: Layer or coat of paint or other material applied to a surface.

FINISH COAT: Last coat of paint or other finish.

FISH-EYE: Small circular depressions nearly devoid of paint usually caused by surface contamination with oils or silicones

FLASH: The time required for the majority of the quick-evaporating solvents in the material being sprayed to evaporate or "flash" from the surface.

FLASH POINT: The temperature at which a coating or solvent will ignite.

FLAT: A painted surface that scatters or absorbs the light failing on it, so as to be substantially free from gloss or sheen.

FLEXIBILITY: Ability of a coating to expand and contract during temperature changes.

FLOATING: Separation of pigment colors on the surface of applied paint.

FLOWOUT: The desirable characteristic of droplets of sprayed material to meld together and level into a glass-smooth surface. Air pressure, gun atomization, and the amount of material being applied as well as the mixture of the paint all affect flow

G

GALVANIZED: A thin coating of zinc that covers iron or steel to prevent rust.

GLAZE: Material used to fill minor imperfections or improve the surface quality of body filler. Glazing putty was traditionally a single-component acrylic, although today catalyzed putties are available that reduce shrinkage. Fine grain and easy sanding are the main characteristics of glaze.

GLOSS: The luster or shininess of paints and coatings are generally classified as flat, semi-gloss, or gloss; the latter has the highest reflecting ability.

GLOSS METER: A standard scale for measuring the shininess light reflectance of paint.

H

HARDNESS: The ability of a paint film to resist denting, scratching, or marring.

HOLD-OUT: The ability of a paint film to dry to its normal finish on a somewhat absorptive surface.

HVLP: Stands for High-Volume, Low-Pressure; it refers to the design of modern spray equipment, initially introduced to meet air-quality regulations by reducing airborne overspray.  

I

INHIBITOR: Material such as primer used to retard rusting or corrosion.

INTERCOAT ADHESION: The adhesion between two coats of paint.

INTERMEDIATE COAT: The coating between the primer and finish, often called a barrier coat.

J

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K

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L

LACQUER: The old standard for custom paint work, lacquers are a distinct paint type characterized by fast drying times and the ability to be polished to a beautiful luster. Poor durability and chemical resistance are the downside.

LAP: To lay or place one coat so its edge extends over and covers the edge of a previous coat, causing an increased film thickness.

LEVELING: Ability of a film to flow out free from ripples, pock- marks, and brush marks after application.

LIFTING: The softening and penetration of a previous film by solvents in the Paint being applied over it, resulting in raising and wrinkling.

LIGHTFASTNESS: No loss of color due to exposure to light, heat, or weathering.

M

MASKING: Temporary covering of areas not to be painted.

MASKING TAPE: A strip of paper or cloth similar to adhesive tape, which can be easily removed, used to temporarily cover areas that are not to be painted.

METALLICS: A class of paints that include metal flakes in their composition.

MINERAL SPIRITS: Paint thinners or solvents derived from petroleum.

Mixing Ratios: The amount of various components in the proper proportion to produce the final mix for spraying.  

N

NONVOLATILE: The portion of a paint left after the solvent evaporates; sometimes called the solids content.

O

OPACITY: Ability of a paint to hide the previous surface or color.

OPAQUE COATING: A coating that hides the previous surface coating.

ORANGE PEEL: A surface flaw in which the paint goes on with too much texture. Usually caused by improper reducing or air pressure.  

P

PAINT GAUGE: Instrument for measuring the thickness of paint film.

PAINT REMOVER: A compound that softens old Paint or varnish and permits scraping off the loosened material.

PEELING: Detachment of a dried paint film in relatively large pieces, usually caused by moisture or grease under the painted surface.

PIGMENTS: Paint ingredients mainly used to impart color and hiding power.

PIN HOLES: Small pin-sized holes in the paint, resulting from too much solvent, inadequate flash time, or surface contamination.  

POLYURETHANE: Wide range of coatings, ranging from hard glossy enamels to soft flexible coatings. Good to very good adhesion, hardness, flexibility, and resistance. Surface preparation critical.

POT LIFE: Amount of time after mixing a two-part Paint system during which it can be applied.

PRIME COAT OR PRIMER: The first coat or undercoat that helps bind the top coat to the substrate.

PROPELLANT: The gas used to expel materials from aerosol containers.

Q

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R

REDUCER: A solvent used to thin (reduce) enamels, urethanes, and epoxies.

REMOVERS: Substances used to soften old paint so they may be removed easily.

RESIN: A natural or synthetic material that is the main ingredient of paint and that binds ingredients together. It also aids adhesion to the surface.

RUNS: Blemished film caused by excessive flow of coating.

RUST PREVENTIVE PAINT OR PRIMER: The first coat of paint applied directly to iron or steel structures to slow down or prevent rust.

S

SAGS: Excessive flow, causing runs or sagging in paint film during application. Usually caused by applying too heavy a coat of paint or thinning too much.

SEALER: A thin liquid applied to seal a surface, to prevent previous paint from bleeding through from the surface, or to prevent undue absorption of the topcoat into the substrate.

Sealing Primer: A primer used to isolate the existing substrate, or to provide some filling and surface enhancement under the final finish.

SEEDS: Small, undesirable particles or granules other than dust found in a paint.

SETTLING: Paint separation in which pigments and other solids accumulate at the bottom of the container.

SHRINKAGE: The characteristic of paint or filler to "shrink" with time as a full cure is reached, making surface flaws and sanding scratches reappear. Common with lacquer-based primers or acrylic spot putties.

SILICONE: See Resin.

Single-Stage: A paint system in which the color and gloss properties are both contained in a single topcoat product.

SKIN: Tough covering that forms on paints if container is not tightly sealed.

SOLIDS: See Nonvolatile.

SOLVENT: The volatile part of paint composition that evaporates during drying.

SPOT PRIMING: A method for protecting localized spots. The only areas primed are those that require additional protection due to rusting or peeling of the former coat.

SPRAYING: A method of application in which the coating material is broken up into a fine mist that is directed onto the surface to be coated.

STREAKING: The irregular occurrence of lines or streaks of various lengths and colors in an applied film; usually caused by some form of contamination.

STRIP: Removal of old finishes with paint removers.

STYRENE-BUTADIENE: See Resin.

SUBSTRATE: Surface to be painted.

SURFACING PRIMER or PRIMER/SURFACER: A primer designed specifically to build thickness for filling shallow surface flaws by sanding.

 T

TACK RAG: A piece of loosely woven cloth that has been dipped into a varnish oil and wrung out. When it becomes tacky of sticky, it is used to wipe a surface to remove small particles of dust.

TACKY: Sticky condition of coating during drying, between wet and dry-to-touch stage.

TEXTURE: The roughness or irregularity of a surface.

THINNER: Solvent used to thin lacquer-based products – similar to REDUCERS used in enamels & urethanes.

TOUCH UP: The ability of a coating film to be spot repaired (usually within a few months of initial painting) without showing color or gloss differences.

TWO STAGE: A paint system in which the color is applied as a primary product (basecoat) followed by a clearcoat to provide gloss and reflectivity.

U

UNDERCOAT: A primer or intermediate coating applied before the finish coating.

URETHANE: Similar to acrylic enamels, but using urethane resins. Urethane has most of the desirable features of acrylic enamel but with enhanced durability, although they generally dry slower.

V

VEHICLE: The liquid portion of a paint composed mainly of solvents, resins, or oils.

VISCOSITY: The thickness of a coating as related to its ability to flow as a liquid.

VOC: Volatile organic chemicals; the VOC level of the final sprayable mix of the various paint and undercoat products is highly regulated in some regions.

 W

WATER SPOTTING: A Paint appearance defect caused by water droplets.

WEATHERING: The effect of exposure to weather on paint films.

WET EDGE: Length of time paint can stand before applying additional material without showing a lap.

WET-SANDING: Sanding with wet-type sandpaper with water to clean away the sanding debris. Creates a higher-quality surface than dry sanding and makes the paper last longer without clogging up.  

WRINKLING: Development of ridges and furrows in a paint film when the paint dries.

X

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Y

YELLOWING: Development of a yellow color or cast in white, pastels, colored, or clear finishes.

Z

ZINC CHROMATE: Rust-inhibiting Pigment, greenish-yellow in color, that are used with a high-hiding pigment.