A glossary of finishing terms
by Rick Hill
Acrylic - A family of synthetic resins made from acrylic acids.
Adhesion - The ability of one material to stick to another.
Alkyd - A family of synthetic resins made from organic acids, combined with oils and alcohols.
Alligatoring - A reference to a certain failure in paint that looks similar to an alligator hide. Also known as checking.
Binder - An ingredient or blend of ingredients in stain that holds the pigment particles together.
Bleeding - A reaction in the stain or dye that causes the pigment to rise to the surface of the wood.
Blushing - Trapped solvent or moisture in the finish that gives a white/grey cloud look to the coating. It can appear in spots or across the entire piece.
Bridge - The ability of the coating to dry over a crack or void in the wood.
Bubbles - The formation of air bubbles in the top of the finish
Catalyst - An agent that is added to finish that causes a reaction in the coating. This reaction causes the finish to be more durable than without the catalyst.
Checking - Small cracks or lines in the finish. Also known as alligatoring.
Cold Checks - The cracking of a finish due to exposure to cold temperatures.Usually exposure happens before the finish has completely cured.
Craters - The appearance of small holes or depressions in the finish. Also known as fisheyes.
Crazing - Very fine lines or crystalline patterns in the finish usually caused by too much catalyst.
Cross linking - The molecular reaction in a finish from adding catalyst that causes the finish to harden more than without added catalyst.
Distressing - Intentionally marking, gouging or scratching a finish to give the piece an antique look.
Dye - A type of color that soaks into the fibers of the wood instead of being left on top like pigment. Commonly used to evenly color wood before staining.
Filler - A very heavy bodied, slow drying pigment used to fill in grain and create a flat, smooth surface to topcoat.
Fish Eye - A small crater or depression in the finish. Often caused by silicone or oil contamination.
Flatting Paste - An additive used to reduce the sheen or gloss of a finish.
Flash Point - The temperature at which a finish will ignite when exposed to a flame.
Flow-out - The ability of a liquid to level itself as it dries.
Ford Cup - A brand of viscosity cup.
Glazes - Slow setting heavy bodied pigment stains commonly used to accent grain or for other color accents like antiquing.
Gloss - The sheen or reflectivity of a coating.
HAPS - (Hazardous Air Pollutants Incompatibility) - The inability of one finish product to work with another product.
Lacquer - A generic term for finishes using nitrocellulose as a main ingredient.
Lifting - The separation of one coat from another often seen as "alligatoring" or checking".
Mar - A scratch or rub mark on the finish.
Mar Resistance - The ability of a finish to resist scratch or rub marks.
Mil - One thousandth of an inch. 0.001.
N.G.R. - (Non-Grain-Raising) - Usually refers to certain stains that do not raise the fiber of the wood when applied.
Nitrocellulose - Lacquer's main ingredient. A very flammable material that has a tendency to yellow with exposure to sunlight.
Opaque - The opposite of transparent. The hiding quality of a pigmented coating.
Orange Peel - A rough finish surface reminiscent of an orange peel's texture.
Pigment - The raw ground colorant used to give a stain its tone.
Pinholes - Small holes in a finish.
Primer - A specialized coating made for application to raw wood as a first step in a finishing process.
Precats - A finish that arrives already catalyzed from the manufacturer.
Reducer - Thinner.
Sags - A ripple in the coating caused by excessive millage when sprayed. Usually seen on vertical surfaces.
Sealer - An undercoat of finish who's function is to stop further absorption of successive coats into the wood, thus helping the successive coats to level.
Stearate - An additive to the coating or to sandpaper that makes it sand easier.
Substrate - The material or product to be coated.
Toner - A pigmented sealer or topcoat reduction that is used to color certain areas of the wood over the existing stain, giving a uniform look to the stain.
Topcoat - The final finish coat, usually a specific finish product designed to give better flow out and durability than the sealer coat.
VHAPS - Volatile Hazardous Air Pollutants.
Viscosity - The thickness of a coating in its liquid state.
Viscosity Cup - A small cup used to measure the thickness of a coating.
V.O.C. - (Volatile Organic Compound) - The solvent ingredients in a finish.
Washcoat - A reduced finish that is applied over raw wood to reduce stain penetration, or over stains and fillers to promote adhesion of the next coat.
Waterbase - A coating that uses water as the main vehicle for carrying the resins of a finish.
Water White - A high grade of lacquer that shows very little amber tone when applied.
Zahn Cup - A brand of viscosity cup.
Rick Hill is an independent representative and consultant for industrial wood finishes. He has been involved in the woodworking industry for 12 years, and has been known to actually hold, shoot, and clean a spray gun.
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