Glossary
Wood Veneer Industry – Glossary Of Terms
.005″ Paper
A backing material typically used to back wood veneer sheets. These sheets are then “flexed” to make the flexible. Sheets may be cut into strips, or joined into continuous rolls. .005″ refers to the nominal thickness of the paper.
.010″ Paper
A backing material typically used to back wood veneer sheets. These sheets are then “flexed” to make the flexible. Sheets may be cut into strips, or joined into continuous rolls. .010″ refers to the nominal thickness of the paper.
Acclimating
The exposure of a wood to the influence of a prescribed atmosphere for a stipulated period of time, or until a stipulated relation is reached between material and atmosphere. Allowing the wood laminate, and the substrate to equalize in moisture content and temperature.
Adherend
The substrate or surfaces to which adhesive is applied; the surfaces to be bonded together.
Adhesion
The process of bonding two or more things together.
Adhesive
Any of many types of products designed to fasten two surfaces together.
Annual Growth Ring
The growth layer put on by a tree in a single year, including summer wood and spring wood.
Architectural Woodworking Institute
A trade association that represents the manufacturers of Architectural millwork and paneling. Portions of this standard are adapted from their standards.
Back
The reverse side to the face of a sheet or strip or roll of backed veneer.
Backer
A product added to the reverse side of several different products ( wood veneer, polyester, vinyl etc.) generally a non-woven fiber product (paper).
Bag Molding or Pressing
A moulding or bonding process involving the application of pressure by means of air, water, steam, or vacuum, to a flexible cover (bag) which completely encloses the material being bonded.
Balance Matched
Two or more veneer components or leaves of equal size (prior to edge trimming) to make up a single face.
Bark Pocket
Comparatively small area of bark around which normal wood has grown.
Basis Weight
Basis weight or base weight. Used to define printed papers. This is the weight of paper before impregnation, printing, and topcoating. The weight is specified in grams per square meter.
Birds-eye
A figure common in maple. It consists of many small circular or elliptical areas resembling a bird’s eye. It is caused by local fiber distortions. This characteristic is often defined as to quantity or size. Typical terms used are heavy eye or medium eye. Heavy eye is defined by some manufacturers as 100 or more eyes per square foot, averaged over the panel or sheet. Medium eye is defined as 50 eyes per square foot, averaged over the panel or sheet.
Bleed Through
Glue or components of glue that have seeped through the outer layer of a glued wood product and that shows as a blemish or discoloration on the surface.
Blending
Color change that is detectable at a distance of 6’ to 8’ but which does not seriously detract from the overall appearance of the panel or sheet.
Blister
A spot or area where veneer or backing does not adhere and bulges like a blister. It may be caused by a lack of glue or adhesive or inadequate pressure.
Blocking
An undesired adhesion between touching layers of material with or without adhesive. Typically in rolls that bond along one edge, or in spots.
Bloodline
Grain patterns of dark red streaks typical in mahogany species.
Blushing
Formation of condensation on the surface of a contact adhesive as the solvent evaporates ands its temperature is rapidly lower. This blushing will not allow the adhesive to cure.
Boil Test
A test designed to determine water resistance in various products. (See JCD 158 Test for Profiles ). Products are subjected to boiling water for various periods of time.
Book Match
A type of veneer match in which every other piece of veneer is turned over, or opened like the pages of a book.
Bubble
An internal void or trapped globule of air or other gas which occurs during mastic application. Different than a blister, which occurs after application
Burl
A swirl or twist in the grain of the wood which usually occurs near a knot or crotch but does not contain knot.
Cambium
A thin layer of tissue between the bark and the wood in a tree which repeatedly subdivides to form new wood and bark cells.
Catalyst
A hardener for resin adhesives. A reagent that accelerates a chemical reaction, with or without heat. In the case of resinous adhesives, it accelerates setting or hardening. Generally an acid, or isocyanate (initial stage of polyurethane).
Cell
General term for the minute units of wood structure, including wood fibers, vessel segments and other elements. Usually considered as the small openings that contain the water in wood.
Center Match
An even number of veneer components or leaves of equal size (prior to edge trimming) matched with a joint in the center of the panel or sheet to achieve horizontal symmetry.
Centipoise
A unit of measure used to determine viscosity; typically used in defining adhesives, and some finishing materials.
Checks
Small cracks running parallel to grain of wood, caused chiefly by strains produced in seasoning. These are different from flexor cracks which are small cracks put into wood as a result of mechanical flexing process.
Cohesion
The state in which the particles of a single substance are held together, as opposed to adhesion where two different substances are held together,
Comb Grain
A quality of rift veneer with exceptionally straight grain and closely spaced growth increments.
Commercial Match
A color or pattern match that in the general industry would be considered as an acceptable match.
Component (of face)
An individual piece of veneer that is joined to other pieces to achieve a full length and width face. Piece and Leaf are terms used interchangeably with component in the context of a face.
Compression Wood
Abnormal wood formed on the lower side of branches and inclined trunks of trees. Sometimes mistaken for WIND SHAKE – this wood ruptures during drying and creates areas that accept stains and finishes differently than surrounding areas.
Conditioning (see Acclimating)
The exposure of a wood to the influence of a prescribed atmosphere for a stipulated period of time, or until a stipulated relation is reached between material and atmosphere.
Contact Adhesive
A group of either water base or solvent base adhesives. These types of adhesives are coated on both surfaces of products to be laminated. Characterized by very high green strength, and fast set-up times.
Core
The substrate to which a veneer face or sheet is applied. May be particle board, medium density fiberboard, hardboard, plywood, or any number of less traditional materials.
Crazing
Fine cracks that may extend in network within or beneath the surface of a finish or film. The formation of fissures and voids in a film due to shrinkage or solvent action.
Crossbar
Type of figure or irregularity of grain resembling a dip in the grain running at right angles, or nearly so, to the length of the veneer.
Cross Break
Separation of the wood cells across the grain. Such breaks may be due internal strains resulting from unequal longitudinal shrinkage or due to external forces.
Cross Grain
A veneer face or sheet where the dimension across the grain is greater than the length dimension.
Cross Linking
The union of adjacent molecules of uncured adhesives by catalytic or curing agents.
Custom Match
A special match of color, pattern or gloss level in a product. The match is produced specifically for a user, and is not part of a suppliers standard offering.
Cure
To change the physical properties of an adhesive by chemical reaction, which may be condensation, polymerization, or vulcanization. Usually accomplished by the action of heat and catalyst, alone or in combination, with or without pressure.
Curing Agent
Synonymous with accelerator, hardener, and catalyst. Typical references in adhesives and finishes.
Customer
In profile wrapping, the company that buys a finished wrapped profile for use in their manufacturing process or as a finished product.
Decay
The decomposition of wood substance by fungi. The incipient stage is characterized by discoloration, and may be accompanied by a softening of the wood substance. The final or ultimate state is characterized by partial or complete collapse of the wood structure.
Defect, Open
Checks, splits, open joints, knotholes, cracks, loose knots, wormholes, gaps, voids, or any other opening interrupting the smooth continuity of the wood surface.
Delamination
The separation of the surface veneer from the paper or other backing. This also refers to the separation of the component veneer sheet, strip or roll from the substrate.
Discolorations
Stains in wood substances. Common veneer stains are sap stains, blue stains, stain produced by chemical action caused in the iron in the cutting knife coming in contact with the tannic acid in the wood, and those resulting from chemical action of the glue.
Doze
A form of incipient decay characterized by a dull and lifeless appearance of the wood, accompanied by a lack of strength and softening of the wood substance.
Edgebanding
A veneer of some material designed to cover the exposed edge of a substrate. Edgebanding is typically manufactured to match some surface treatment. Edgebanding is manufactured in many different types of products. Wood veneer, PVC, polyester, melamine, and vinyl are common.
Embossing
a mechanical or chemical process that puts texture into an otherwise smooth finish. Embossing is most often done on vinyl and paper products used in the profile wrapping industry.
Equilibrium Moisture Content
The moisture content at which wood neither gains nor loses moisture when surrounded by air at a relative humidity and temperature.
Exudates
Secretions such as resin, gum, oil, or latex over the surface of veneer. Excessive secretion of such exudates can adversely affect some gluing and finishing operations. Very typical in rosewoods, and Teak
E V A
Ethylene Vinyl Acetate — Hot melt adhesive. An adhesive that melts at high temperatures and cools quickly. Used extensively in the profile wrapping industry.
Face
The veneer side of flexible veneer sheets. Also an assembly of veneer components into a full width and length veneer surface.
Few
A small number without regard to their arrangement on a panel or sheet.
Figure
The pattern produced in a wood surface by annual growth rings, knots, deviations from natural grain such as interlocked and wavy grain, and irregular coloration.
Flake, Ray
Portion of a medulary ray as it appears on the quartered surface. Flake can be a dominate appearance feature in oak and is sometimes referred to as fleck.
Flat Grain
Veneer cut so that the growth rings on more than half of the width of the piece make an angle of less than 45 degrees with the surface. Also called slash grain.
Fleck
See Flake, Ray.
Flexwood™
Trademarked name for flexible wood veneer sheets manufactured by Flexible Materials Inc.
Fiber
A long narrow, tapering wood cell closed at each end.
Filler
A substance used to fill holes, voids, or areas of open joints. Typically a wood flour, often tinted to match surrounding wood color. Also used to describe a substance applied to the entire surface of wood during the finishing process, to reduce the porosity of the surface.
Finger Joint
See Joint, Finger.
Finish Sanding
refers to the smoothness of the sanding of a piece of wood or veneer. Usually referred to as a grit specification (ie. 100 grit). The higher the grit number, the smoother the finish. For substrates and veneer sheets and rolls, 100 grit is typical.
Flame Spread Rating
An index or classification indicating the extent of spread of flame on the surface of a material, or an assembly of materials, as determined in a standard fire test as prescribed in building codes. (ASTM 84 Tunnel Test) The ratings are relative to solid red oak lumber, which is rated at 200.
Flat Cut
Veneer sliced parallel to the pith of the log and approximately tangent to the growth rings. See Plain Sliced.
Fleece
A backer that is applied to wood veneer in a lineal process to produce continuous rolls for profile wrapping.
Flexed
refers to wood veneer sheets, strips or rolls that have been mechanically processed to allow them to bend to tighter radii and reduce cracking.
Flexibility
the ability of a profile wrapping material to bend around various curves and radii. Thinner products are generally more flexible that thicker products of the same type.
Foil
term used to describe finished and topcoated papers.
Gap
Open slits or improperly joined veneers.
Gloss – or gloss level
A measurement of the reflection of light off a finished product. Measured using a gloss meter it is expressed as a numerical reading. The higher the gloss level, the shinier the surface.
Glue Line
The specific type of adhesive used to bond either the veneer to the backer, or the backed veneer product to the substrate. Customarily applied to the older conventional cold setting adhesives, but now generally accepted as being synonymous with adhesive.
Grain
The direction, size, arrangement, and appearance of the fibers in the veneer.
Grain Rupture
Veneer with slight breaks from improper cutting or irregular grain.
Grain Slope
Expression of the angle of the grain to the long edges of the veneer.
Grain Sweep
Expression of the angle of the grain to the long edges of the veneer, over the area extending one eighth of the length of the piece from the ends.
Grit
the measurement of the coarseness or smoothness of sandpaper. The higher the grit, the more particles of grit per square inch, and therefore the smother the finish. Referred to as a number, (ie. 100 grit)
Gum Pockets
Well defined openings between rings of annual growth, containing gum or evidence of prior gum accumulations.
Gum Spots
Gum or resinous material or color spots caused by prior resin accumulations sometimes found on panel surfaces. Gum spots can often be removed by sanding.
Hairline
Thin, perceptible line showing at the joint of two pieces of wood.
Half-round
Veneer produced in the same manner as rotary cutting, except that the piece being cut is secured to a “stay log,” a device that permits the cutting of the log on a wider sweep than when mounted with its center secured in the lathe. A type of half-round cutting may be used to achieve “flat cut” veneer.
Hardboard
A panel manufactured primarily from interfolded wood fibers
consolidated under heat and pressure in a hot press. Used as a substrate for some
veneer products.
Hardwood
General term used to designate lumber or veneer produced from broad-leafed or deciduous trees in contrast to softwood, which is produced from evergreen or coniferous trees.
Hardwood Plywood and Veneer Association
a trade association for plywood manufacturers, and veneer producers. Portions of this glossary are adapted from their standards.
Heartwood
The non-active center of a tree generally distinguishable from the outer portion (sapwood) by its darker color.
High Pressure Laminate
decorative papers that are laminated over Kraft papers impregnated with phenolic resins.
Hot Melt
EVA adhesive. 100% solids adhesive requiring heat to rise the temperature of the adhesive to a workable viscosity.
Holes, Worm
Holes resulting from infestation of worms.
Humidity, Relative
Ratio of the amount of water vapor in the air to the maximum amount of water vapor the air can hold at a given temperature.
Inconspicuous
Barely detectable with the naked eye at a distance of 6’ to 8’.
Joint
The line between the edges or ends of two adjacent sheets of veneer or strips of lumber in the same plane.
Joint, Butt
A type of linear joint in wood veneer where the individual veneers or sheets are “butted” together.
Joint, Edge
Joint running parallel to the grain of the wood.
Joint, Finger
The process of cutting “fingers” in individual veneers, or laid up sheets of veneers to make joints to allow continuous rolls of veneer to be manufactured.
Joint, Open
Joint in which two adjacent pieces of veneer do not fit tightly together.
Knot
cross section of tree branch or limb with grain usually running at right angles to that of the piece of wood in which it occurs.
Knot, Open
Opening produced when a portion of the wood substance of a knot has dropped out, or where cross checks have occurred to produce an opening.
Knotholes
Openings produced when knots drop from the wood in which they were originally embedded.
Knots, Blending, Pin
Sound knots ¼” or less in diameter that do not contain dark centers. Blending pin knots are detectable at a distance of 6’ to 8’ and do not seriously detract from the overall appearance of the panel or sheet.
Knots, Pin
Sound knots less than 1/4 inch in diameter.
Knots, Sound Tight
Knots that are solid across their face and fixed by growth to retain their place.
Laminating Materials Association
a trade association of suppliers of materials commonly used in the profile wrapping industry. The sponsor for these standards.
Lap
A condition where one piece of veneer in the same ply overlaps an adjacent piece.
Lathe
The equipment used to cut rotary and half round veneer. Source of the term lathe checks. See Loose Side.
Length
The dimension of veneer when measured parallel with the grain.
Loose Side
In knife-cut veneer, that side of the sheet that was in contact with the knife as the sheet was being cut, and containing cutting checks (sometimes called lathe checks) because of the bending of the wood at the knife edge.
Manufacturer
A company which takes the various elements of profile wrapping and manufacturers them into a wrapped profile.
Matching
The process of laying out veneers into a pattern when manufacturing wide sheets or panels. (see Book Match, Slip Match).
Melamine Paper
Base papers, with resins added on-line in the paper manufacturing process. The resins are several different chemicals, including melamine. Referred to by the Laminating Materials Association as Decorative Foil Overlays.
Mil
One-one thousandth of an inch. 1/1000″. In the profile wrapping industry generally used to define paper backings on wood veneers, and vinyl thickness’.
Mineral Streak
Olive to greenish black or brown discoloration. These show regions of concentrations of mineral matter in some hardwoods. It is common in maple, hickory and basswood.
Moisture Content
Sometimes abbreviated as MC. This is the amount of water contained in wood, usually expressed as a percentage of the weight of the oven dry wood.
Moisture Meter
A device for measuring the moisture content of wood.
National Window and Door Association
A trade association of window and door manufacturers. Portions of this glossary were adapted from their standards.
Patches
Insertions of filler material or sound wood plugs or shims placed and glued into veneers or panels from which defective portions have been removed.
Patches, Inconspicuous
Elongated patches which are similar in color and grain to adjacent wood so as to blend well.
Pitch Pocket
An opening extending parallel to the annual growth rings containing pitch.
Pitch Streak
A well defined accumulation of pitch in a more or less regular streak.
Platform
Sometimes used to describe a substrate for a veneered panel. May be MDF Particleboard, or a veneer core.
Plain Sliced
Veneer sliced parallel to the pith of the log and approximately tangent to the growth rings to achieve flat cut veneer. Also referred to as Flat Cut
Pleasing Match
A face containing components which provides a pleasing overall appearance. The grain of the various components need not be matched at the joints. Sharp color contrasts at the joints of the components are not permitted.
Ply
A single sheet of veneer, or several pieces laid with adjoining edges, which form one layer in a piece of plywood. Also, when two or more full sized sheets of veneer are combined in thickness so that the grain of each sheet is in the same direction.
Plywood
A glued wood panel made up of thin layers of wood veneer with the grain of adjacent layers at right angles, or of veneer in combination with a core of lumber or of reconstituted wood like Medium Density Fiberboard or Particleboard.
Poises
A unit of measure used to determine viscosity; typically used in defining adhesives, and some finishing materials.
Polyamide
A hot melt adhesive with high heat resistance and better performance than EVA hot melt adhesives.
Polyurethane
Both a finish supplied as a varnish like substance, and as the basis for adhesive curing systems.
Post-impregnated
Papers that have resins added off line after production.
Pressure Sensitive Adhesive
An adhesive film applied to the back of flexible veneer sheets. Typically @ .005” thick, and protected by a removable liner.
Pre-cure
The setting of adhesive, in an assembly process, before sufficient pressure for proper bonding is applied.
Pre-impregnated
Papers that have resins added in line during the manufacturing process.
Printed Vinyl
PVC that has been printed (usually on the back side) with a pattern or color. In profile wrapping, typically a wood grain pattern.
Profile
The substrate, typically milled or extruded to some specific shape that is wrapped in profile wrapping. Profiles are generally lineal in dimension.
Profile Wrapping
The process of wrapping a profiled substrate with some type of veneer. The veneer may be high pressure laminate, paper, vinyl, wood veneer, or some other material. The end result is a profile (or moulding) with a surface different from the substrate.
PVA – PVAc – Poly Vinyl Acetate (white glue)
A common wood adhesive An adhesive sometimes used in the profile wrapping industry. Also typically used to hold wood veneers to fleece backing for ultimate use as a wrapping material.
PUR
Polyurethane reactive hot melt adhesive. A moisture curing hot melt adhesive with the advantages of hot melt adhesives with the additional ability to generally create a Type I glue line.
Quartered
Veneer produced by cutting in a radial direction to the pith to the extent that ray flack is produced, and the amount may be unlimited..
Radius
A measure of circular area. In profile wrapping, it defines the sharpness of a curve or of an inside or outside corner.
Raised Grain
A roughened condition of the surface of veneer where the hard latewood is raised above the softer earlywood, but not torn loose from it. In veneer. generally caused by uneven moisture absorption.
Ray
Strip of cells extending radially within a tree. See Flake, ray
Rift Cut
Veneer produced by cutting at a slight angle to the radial to produce a quartered appearance without excessive ray flake.
Rotary Cut
Veneer produced by centering the entire log in a lathe and turning it against a broad cutting knife which is set into the log at a slight angle.
Rough Cut
Irregular shaped areas of generally uneven corrugation on the surface of veneer, differing from the surrounding smooth veneer and occurring as the veneer is cut by the lathe or slicer.
Sapwood
The living wood of lighter color occurring in the outer portion of a tree. Sometimes referred to as “sap”.
Sanding Tolerance
The thickness to which veneer sheets or rolls are sanded. It is expressed in thousands of an inch (ie. .016″ thick). The thickness may generally be controlled to +/- .002″.
Shake
A separation along the grain of wood in which the greater part occurs between the rings of annual growth. Generally occours in standing wood, or sometimes during felling.
Sharp Contrasts
For purposes of this Standard, this term means that face veneer of lighter than average color should not be joined at the edges with veneer of darker than average color and that two adjacent pieces of veneer should not be widely dissimilar in grain, figure, and other natural character markings.
Side Seam
the seam where two pieces of veneer are joined parallel to the grain direction. The seam used to join veneers into wide sheets or panels.
Sliced
Veneer produced by thrusting a log or sawed flitch into a slicing machine which shears off the veneer in sheets.
Slip Match
A type of veneer match where all veneers are layed out, without turning any over. (ie. slipped off the stack of veneer).
Smooth, Tight Out
Veneer carefully cut to minimize lathe checks.
Softening Point
The temperature at which an adhesive commences to flow or soften. Especially used to describe hot melt adhesives.
Softwood
General term used to describe lumber or veneer produced from needle and/or cone bearing trees. (See “HARDWOOD”.)
Solid Core
Plywood panels in which the inner plies are free from voids.
Species
A distinct kind of wood.
Splice
In paper, polyester or vinyl rolls, a point where there is a break in the roll, and it has been joined together.
Splits
Separations of wood fiber running parallel to the grain.
Springwood
The portion of the annual growth ring of a tree that is formed during the early part of the seasons growth. It is usually less dense and weaker mechanically than the summerwood.
Straightness
In roll goods refers to how straight a roll of material is when unwound from the roll.
Streaks, Mineral
Natural discoloration’s of the wood substance.
Summerwood
The portion of the annual growth ring that is formed after the springwood formation has ceased. It is usually denser and stronger mechanically than springwood.
Supplier
A company that sells to a manufacturer, one of the elements of their product ie. a substrate, adhesive, faces or wrapping material.
Substrate
Synonymous with adherend, generally used to refer to what ever a veneer is adhered to. In the veneer business typically particle board, medium density fiberboard, plywood etc.
Tape
Strips of gummed paper or cloth sometimes placed across the grain of large veneer sheets to facilitate handling and sometimes used to hold the edges of veneer together at the joint prior to gluing.
Telegraphing
A visible pattern on the surface of a substrate. Usually the pattern of an irregular substrate, or the application pattern of the adhesive.
Thickness
The dimension representing a cross section of a piece of paper, vinyl, or wood veneer.
Thermoplastic
The ability to be repeatedly softened by heat, and hardened by cooling. In adhesives, the ability to reactivate adhesive with heat. For example hot melt adhesive (see EVA)
Thermoset
Substances that are cured by heat, but do not soften when subsequently subjected to high temperatures.
Tight Side
In knife-cut veneer, that side of the sheet that was farthest from the knife as the sheet was being cut and containing no cutting checks (lathe checks).
Top Coat
A coating or finish applied to either a paper or a wood veneer to give it a finished appearance. Top coats may consist of a wide range of products.
Type 1 Glue Line
A glue line that meets various tests for water resistance. This term refers to both the glue line that holds veneer to the backing and the glue line that holds the veneer product to the substrate. The test for this is the JCD.158 Test. Finished wrapped profiles are submitted to the test. Most veneer products, although “Type 1” will not pass the test without being laminated to the profile. This glue line is most typically a PVAc adhesive holding the veneer to the backing, and a PUR adhesive holding the veneer product to the substrate. (See PVAc & PUR)
Un-impregnated
A paper with out resins added, except for a small quantity to help in binding of the fibers.
Veneer
A thin sheet of wood, rotary cut, sliced, or sawed from a log, bolt, or flitch. Veneer may be referred to as a ply when assembled into a panel.
Viscosity
The property of a liquid which causes it to resist flow or movement. It is measured in standard units called poises. (Typically referred to as centipoise). The higher the number, the thicker, or more viscous the liquid.
Width
The dimension of a wood veneer measured perpendicular to the grain dimension.
Wind Shake
A rupture and compression of grain. Caused by the stress put on trees during excessive wind. These areas are different in density than surrounding fibers, and take stains and finishes differently that surrounding fibers. Sometimes called Compression Wood.
Wood Filler
An aggregate of resin and strands, shreds, or flour of wood which is used to fill openings in wood and provide a smooth durable surface.
Yield
The amount of finished product that is realized from a flitch. Expressed as a percentage.