Glossary 

Glossary

A

“Appleply”: A trade name of States Industries for a proprietary plywood panel product composed of a core of 1/16" Western Red Alder veneers most commonly available with face veneers of Maple or Birch. However, any face or back veneer is available, too. Noted for the attractive decorative appearance of the edge of a panel. See Europly.

"Armorcore": See Composite Core.

B

Backer: A non-decorative laminate used on the back of composite panel constructions to protect the substrate from changes in humidity and to balance the panel construction.

Backs: The reverse side to the face of a plywood panel. Generally, the poorer side of any grade of plywood panel, which has a face and a back.

Balanced Construction: A panel construction that will not warp when subjected to uniformly distributed moisture changes.

Balanced Match: Two or more veneer components or leaves of equal size to make up a single face.

Birdseye: Due to local sharp depressions in the annual rings, accompanied by considerable fiber distortions. Once the depressions are formed, succeeding growth rings follow the same contour for many years. Rotary veneer cuts the depressions crosswise, and shows a series of circlets called birdseyes. It occurs in only a small percentage of maple trees.

Book Match: Adjacent pieces of veneer from a flitch or log are opened like a book and spliced to make up the face, with matching occurring at the spliced joints.

Bow: The deviation from absolute flatness along the length of the panel.

Burl: A swirl or twist in the grain of wood, usually occurring near a knot but which does not itself contain a knot.

C

Cathedral: A grain appearance characterized by a series of stacked or inverted "V" or cathedral-type of springwood (earlywood) summerwood (latewood) patterns common in plain-sliced (flat-cut) veneer.

Centermatch: An even number of veneer components or leaves of equal size matched with a joint in the center of the panel to achieve horizontal symmetry.

Chatter: A wavy condition across the width of a panel caused by sanding. These markings are parallel to one another, between 3 and 2 inches apart and perpendicular to the sander grit markings. Sometimes they can be felt, but can always be seen.

Checks: Small slits running parallel to the grain of wood caused by strains produced in seasoning.

"Classic Core": See Composite Core.

Clear face cutting: A cutting having one clear face (ordinary season checks are admitted) and the reverse side sound as defined in Sound Cutting. The clear face of the cutting shall be on the poor side of the board, except when otherwise specified.

Comb Grain: A quality of rift cut veneer with exceptionally straight grain and closely spaced growth increments.

Composite Core: Any one of a number of different core configurations produced from various combinations of wood veneers and reconstituted or engineered wood fiber materials such as MDF, particleboard and hardboard. This type of core configuration generally provides the advantages of the flatness of the reconstituted wood fiber crossband with the lightness of traditional veneer core.

Core: The innermost portion of plywood, usually composed of veneer. Also referred to as a "center." A core may also be made of fiberboard, particleboard or lumber.

Crossband: Inner ply veneer placed at right angles to the core, face and back of a plywood panel.

Cup: Deviation from a straight line stretched across the width of a panel or board.

Curly: Curly figure is found mostly in maple or birch and is due to the fibers being distorted and producing a wavy or curly effect in the veneer.

D

Delamination: The separation of the panel's face layer from the core, or a laminate from a substrate or separation of the inner plys, usually from failure of the adhesive bond.

Density: The weight of a panel as measured in pounds per cubic foot.

Doze (also Dote): A form of incipient decay characterized by a dull or lifeless appearance of the wood and accompanied by a loss of strength and softening of the wood substance.

E

End Matched: Often called butt matched, the veneers are matched as described for book matched, but the ends of the sheets are matched. Quite often, veneers are both book-matched and end-matched, which is called a four-way match.

Europly: Europly is decorative hardwood plywood that is durable, rigid and resists splitting and warping. It can be used where special strength and high quality, visual edge is required and desired.

F

Face: The best side of a plywood panel in which the outer veneers are of different grades.

Fiberboard: See MDF – Medium Density Fiberboard.

Fiber Raise: Face fibers that are raised above the surrounding surface, causing a rough surface. Usually caused by excessive absorption of moisture.

Fibers: The slender threadlike elements or groups of wood fibers resulting from chemical or mechanical defiberization, or both, and sometimes referred to as fiber bundles.

Fiddle: Back – A fine, strong, even, ripple figure as frequently seen on the backs of violins. It is found principally in mahogany and maple, but occurs sometimes in other woods.

Fines: Small, moist, almost dust-like wood particles found on the surface of the reconstituted wood panel. The presence of fines helps create a smooth, tight surface.

Finger Joint: A series of fingers machined on the ends of two pieces of wood to be joined, which mesh together and are held firmly in position with an adhesive.

Flake, Ray: A portion of a ray as it appears on the quartered surface. Flake can be a dominant appearance feature in oak and is sometimes referred to as fleck.

Flat-Cut: See Plain-Sliced.

Fleck: See Flake.

Flitch: A complete bundle of thin veneer sheets laid together in sequence as they are cut from a given log or section of a log.

G

Gap: Open slits in the inner plys or improperly joined veneers.

Gum Pockets: Well-defined openings between the rings of annual growth containing gum or evidence of prior gum accumulation.

H

Hardboard: A high-quality panel manufactured from specially engineered fibers that are compressed under heat and pressure. The panels, which are produced by a wet process, can have one smooth side and a screen back (smooth one side or S1S) or be smooth on both sides (S2S). Pegboard is commonly manufactured from hardboard.

Hardwood Plywood: Composed mostly of inner plys peeled from fir, poplar, lauan or other species of either soft or hardwood, only the face and back panels are pure hardwood veneers of 1/30th to 1/40th or less of an inch thick.

Hardwood: General term referring to the wood of many different deciduous trees as opposed to the softwood of evergreen or coniferous. Does not relate to the density of wood.

Heartwood: The center portion of a tree consisting of mature wood that has stopped growing. Generally distinguishable from sapwood or the growing outer portion by its dark color.

High Pressure Laminate: A sheet material formed from multiple layers of kraft paper saturated with phenolic resin; a decorative layer of paper saturated with melamine resin; and a very thin top sheet of paper heavily saturated with a melamine resin. Fused together in a hot press under high temperature and pressure to produce a stiff plastic sheet.

Holes, Worm: Resulting from an infestation of worms.

K

Knot: Circular portion of a board or veneer that was once the base of a branch or twig growing from the trunk of a tree.

Knot (Sound): Knots that are solidly fixed by growth and retain their place in lumber or veneer.

Knot (Pin): Sound knots less than 3" in diameter.

Knot (Open): Opening produced when a portion of a knot has dropped out or separated due to seasoning.

L

Loose Side: In knife-cut veneer, that side of the sheet that was in contact with the knife as the veneer was being cut, and containing cutting checks (lathe checks) because of the bending of the wood at the knife's edge.

LPL: Low-pressure laminate. A preprinted or solid color decorative paper that has been saturated with resin. Under heat and pressure, it bonds to a board surface without the need for additional adhesive.

M

MDF – Medium Density Fiberboard: A material consisting of a wood fiber–resin combination formed into a homogenous mat of random fiber orientation, then hot pressed and finished. It can be machined or sanded to a smooth finish.

Melamine: A laminate that derives its name from the melamine resin system used to saturate the paper laminate and adhere it to the substrate. It is the resin that gives durability and toughness to high-pressure plastic laminate and melamine panels. Also, a generic term for panels surfaced with melamine papers.

Mill Run: A downgraded product due to visual defects such as oil stains, resin spots or surface discoloration.

Mineral Streak: A discoloration of hardwood and hardwood veneer.

N

Natural Veneer: Composed of both heartwood and sapwood. Select or uniform heartwood veneers are usually more expensive than their sapwood counterparts since the heartwood is the smallest portion of the tree. Natural veneers are a combination of both heartwood and sapwood and is therefore generally less expensive than Select or Uniform veneers.

O

Occasional: A small number of characteristics that are arranged somewhat diversely within the panel face.

P

Paint Grade Veneer: A lower grade panel, it has, however, a smooth enough finish so none of the grain pattern or natural characteristics of the wood show through when it is painted.

Particleboard: A panel product constructed from wood particles. The wood particles are blended with resin and wax and pressed into panels.  It is firm and solid throughout and makes a good core for hardwood plywood, and, depending on the grade, an excellent underlayment for wood veneers, high-pressure laminate and other overlay materials.

Particles: The aggregate component of a particleboard manufactured by mechanical means from wood, including all small subdivisions of wood such as flakes, shavings, slivers, and wafers. Particle size may be measured by a screen mesh that permits passage of particles and another screen upon which they are retained, or by measured dimensions, as for flakes.

PBU – Particleboard Underlayment: A particleboard product manufactured for interior use as the smooth surface layer under finish floor coverings in double-layer floor construction.

Plain-Sliced (Flat-Cut): Veneer sliced parallel to the pith of the log and approximately tangent to the growth rings to achieve flat-cut veneer. Plain sliced veneer can be cut using either a horizontal or vertical slicing machine or by the half-round method using a rotary lathe.

Q

Quarter Slicing: Quartered log sliced at right angles to the growth rings.

R

Ray Flake: See Flake.

Repairs: A patch, shim or filler material inserted and/or glued into veneer or a panel to achieve a sound surface.

Resin Spots: Hard pieces of dark or black foreign material in the face layer that are composed of glue and wood dust.

Ribbon Stripe: In some woods, principally mahogany, wide, unbroken stripes can be secured. It is produced by cutting on the quarter a log that shows growth rings.

Rift Cut: Veneer cut from a log sliced at right angles to the growth rings.

S

SL1E: Nomenclature used to describe a board with one edge that has been cut straight to facilitate further processing.

S2S: Shorthand for "Smooth 2 Sides." Used to describe material, usually a board, that has been planed smooth on both sides.

S1S: Shorthand for "Smooth 1 Side." Used to describe material, usually a board, that has been planed smooth on only one side. The other side is left rough.

S4S: Shorthand for “Surfaced 4 Sides.” Used to describe lumber that is planed to a uniform thickness, and finished on all four sides, usually sanded to 120 grit. In the UK, this is known as “PAR” or “Planed all round.”

Sand Through: A condition where the face layer has been sanded off, exposing the core. These areas will appear to be darker, and larger particles will be exposed.

Sapwood: The light colored, living portion of a tree located between the heartwood and the bark.

Select Veneer: Composed entirely of heartwood or sapwood and matched for both grain pattern and color.

Shop Grade: A downgraded product due to visual defects (as in Mill Run), which can also have damaged corners, edges, face or back defects such as missing veneer or sanding dips. The panel must be 75% to 90% usable, depending on the nature of the manufacturing.

Slip Matched: Veneer components are laid side by side to form a whole sheet with a repetitive grain appearance.

Smooth, Tight Cut: Veneer carefully cut to minimize lathe checks.

Splits: Separations of wood fiber running parallel to the grain.

Softwood: General term used to describe lumber or veneer produced from needle and/or cone-bearing trees.

Solid Core: Plywood panels in which all inner plys are grade J or better. Splits up to 3.2 mm or 1/8th of an inch are permitted.

Species (Trees): An internationally established botanical classification of trees.

Spliced Veneers: Spliced veneers are composed of several pieces of veneer varying in width that are glued together to form a whole sheet. The way they are laid out during composing determines the final look of the veneer.

Split: A lengthwise separation of the wood in a board or veneer due to the tearing of wood fiber parallel to the grain.

Stain: In hardwoods, the word "stain" is used to describe the initial evidence of decay.

“Superply”: See Composite Core.

T

Tight Side: In knife-cut veneer, that side of the sheet that was farthest from the knife as the sheet was being cut, containing no cutting checks (lathe checks).

U

Unbalanced Construction: Warping caused when the individual layers or components of a panel do not respond equally to changes in moisture or humidity.

Uniform Veneer: Composed entirely of heartwood and sapwood but matched for color only.

V

Veneer: A thin sheet of wood, rotary cut, sliced or sawed from a log, bolt or flitch and used as interior ply or decorative face.

W

Wane: The presence of bark, or the lack of wood from any cause, on the edge or corner of a piece of lumber.

Warp: When a board bends, twists or turns from a straight line due to unbalanced construction, excessive moisture pick up, wetting or other unfavorable exposure.

Whole Piece Veneers: Unspliced continuous pieces of veneer that have been peeled from a log using the rotary process.