Adherend. A body that is held to another body by an adhesive.
Adhesion. The state in which two surfaces are held together by
interfacial forces which may consist of valence forces or interlocking
action or both.
Adhesive. A substance capable of holding materials together by surface
attachment. It is a general term and includes cements, mucilage, and
paste, as well as glue.
Assembly Adhesive---An adhesive that can be used for bonding parts
together, such as in the manufacture of a boat, airplane, furniture, and
the like.
Cold-Setting Adhesive--An adhesive that sets at temperatures below 20 °C
(68 °F).
Construction Adhesive--Any adhesive used to assemble primary building
materials into components during building construction--most cornmonly
applied to elastomer-based mastic-type adhesives.
Contact Adhesive-An adhesive that is apparently dry to the touch and
which will adhere to itself instantaneously upon contact; also called
contact bond adhesive or dry bond adhesive.
Gap-Filling Adhesive--Adhesive suitable for use where the surfaces to be
joined may not be in close or continuous contact owing either to the
impossibility of applying adequate pressure or to slight inaccuracies in
matching mating surfaces.
Hot-Melt Adhesive--An adhesive that is applied in a molten state and
forms a bond on cooling to a solid state.
Hot-Setting Adhesive---An adhesive that requires a temperature at or
above 100 °C (212 °F) to set it.
Room-Temperature Setting Adhesive-An adhesive that sets in the
temperature range of 20 to 30 °C (68 to 86 °F), in accordance with the
limits for Standard Room Temperature specified in the Standard Methods
of Conditioning Plastics and Electrical Insulating Materials for Testing
(ASTM Designation: D 618).
Solvent Adhesive-An adhesive having a volatile organic liquid as a
vehicle. Note: This term excludes water-based adhesives.
Structural Adhesive---A bonding agent used for transferring required
loads between adherends exposed to service environments typical for the
structure involved.
Air-Dried. (See Seasoning. )
Allowable Stress- The value of a property normally published for design
use. Allowable properties are identified with grade descriptions and
standards, reflect the orthotropic structure of wood, and anticipate
certain end uses.
American Lumber Standards. American lumber standards embody provisions
for softwood lumber dealing with recognized classifications,
nomenclature, basic grades, sizes, description, measurements, tally,
shipping provisions, grade marking, and inspection of lumber. The
primary purpose
of these standards is to serve as a guide in the preparation or revision
of the grading rules of the various lumber manufacturers' associations.
A purchaser must, however, make use of association rules because the
basic standards are not in themselves commercial rules.
Anisotropic- Exhibiting different properties when measured along
different axes. In general, fibrous materials such as wood are
anisotropic.
Annual Growth Ring- The layer of wood growth put on a tree during a
single growing season. In the temperate zone the annual growth rings of
many species (e.g., oaks and pines) are readily distinguished because of
differences in the cells formed during the early and late parts of the
season. In some temperate zone species (black gum and sweetgum) and many
tropical species, annual growth rings are not easily recognized.
Assembly Joint- (See Joint.)
Assembly Time- (See Time, Assembly.)
Balanced Construction. A construction such that the forces induced by
uniformly distributed changes in moisture content will not cause
warping. Symmetrical construction of plywood in which the grain
direction of each ply is perpendicular to that of adjacent plies is
balanced construction.
Bark Pocket- An opening between annual growth rings that contains bark.
Bark pockets appear as dark streaks on radial surfaces and as rounded
areas on tangential surfaces.
Bastard Sawn- Lumber (primarily hardwoods) in which the annual rings
make angles of 30° to 60° with the surface of the piece.
Beam- A structural member supporting a load applied transversely to it.
Bending, Steam. The process of forming curved wood members by steaming
or boiling the wood and bending it to a form.
Bent Wood- (See Bending, Steam.)
Bird Peck- A small hole or patch of distorted grain resulting from birds
pecking through the growing cells in the tree. In shape, bird peck
usually resembles a carpet tack with the point towards the bark; bird
peck is usually accompanied by discoloration extending for considerable
distance along the grain and to a much lesser extent across the grain.
Birdseye- Small localized areas in wood with the fibers indented and
otherwise contorted to form few to many small circular or elliptical
figures remotely resembling birds' eyes on the tangential surface.
Sometimes found in sugar maple and used for decorative purposes; rare in
other
hardwood species.
Blister- An elevation of the surface of an adherend, somewhat resembling
in shape a blister on the human skin; its boundaries may be indefinitely
outlined, and it may have burst and become flattened. Note: A blister
may be caused by insufficient adhesive; inadequate curing time,
temperature or pressure; or trapped air, water, or solvent vapor.
Bloom- Crystals formed on the surface of treated wood by exudation and
evaporation of the solvent in preservative solutions.
Blow. In plywood and particleboard especially, the development of steam
pockets during hot pressing of the panel, resulting in an internal
separation or rupture when pressure is released, sometimes with an
audible report.
Blue Stain- (See Stain.)
Board- (See Lumber.)
Board Foot- A unit of measurement of lumber represented by a board 1
foot long, 12 inches wide, and 1 inch thick or its cubic equivalent. In
practice, the board foot calculation for lumber 1 inch or more in
thickness is based on its nominal thickness and width and the actual
length. Lumber with a
nominal thickness of less than 1 inch is calculated as 1 inch.
Bole- The main stem of a tree of substantial diameter--roughly, capable
of yielding sawtimber, veneer logs, or large poles. Seedlings, saplings,
and small-diameter trees have stems, not boles.
Bolt- (1) A short section of a tree trunk; (2) in veneer production, a
short log
of a length suitable for peeling in a lathe.
Bond (noun)-. The joining of materials by adhesives.
Bond (verb)- To unite materials by means of an adhesive.
Bondability- Term indicating ease or difficulty in bonding a material
with adhesive.
Bond Failure- Rupture of adhesive bond.
Bondline- The layer of adhesive that attaches two adherends.
Bondline Slip. Movement within and parallel to the bondline during
shear.
Bond Strength. The unit load applied in tension, compression, flexure,
peel impact, cleavage, or shear, required to break an adhesive assembly
with failure occurring in or near the plane of the bond.
Bow. The distortion of lumber in which there is a deviation, in a
direction perpendicular to the flat face, from a straight line from
end-to-end of the piece.
Box Beam. A built-up beam with solid wood flanges and plywood or wood
base panel product webs.
Boxed Heart. The term used when the pith fails entirely within the four
faces of a piece of wood anywhere in its length. Also cailed boxed pith.
Brashness. A condition that causes some pieces of wood to be relatively
low in shock resistance for the species and, when broken in bending, to
fail abruptly without splintering at comparatively smail deflections.
Breaking Radius. The limiting radius of curvature to which wood or
plywood can be bent without breaking.
Bright. Free from discoloration.
Broad-Leaved Trees. (See Hardwoods.)
Brown Rot. In wood, any decay in which the attack concentrates on the
cellulose and associated carbohydrates rather than on the lignin,
producing a light to dark brown friable residue--hence loosely termed
"dry rot."An advanced stage where the wood splits aiong rectangular
planes, in shrinking, is termed "cubicai rot."
Brown Stain. (See Stain.)
Bunt-Up Timbers. An assembly made by joining layers of lumber together
with mechanicai fastenings so that the grain of all laminations is
essentially parallel.
Buff. (1) A hard, woody outgrowth on a tree, more or less rounded in
form, usuaily resulting from the entwined growth of a cluster of
adventitious buds. Such burIs are the source of the highly figured burl
veneers used for purely ornamentai purposes. (2) In lumber or veneer, a
localized severe distortion of the grain generaily rounded in outline,
usually resulting from overgrowth of dead branch stubs, varying from 1/2
inch to several inches in diameter; frequently includes one or more
clusters of several small contiguous conical protuberances, each usually
having a core or pith but
no appreciable amount of end grain (in tangentiai view) surrounding it.
Butt Joint. (See Joint. )
Buttress. A ridge of wood developed in the angle between a lateral root
and the butt of a tree, which may extend up the stem to a considerable
height.
Cambium. A thin layer of tissue between the bark and wood that
repeatedly subdivides to form new wood and bark cells.
Cant. A log that has been slabbed on one or more sides. Ordinarily,
cants are intended for resawing at right angles to their widest sawn
face. The term is loosely used. (See Flitch. )
Casehardening. A condition of stress and set in dry lumber charactetized
by compressive stress in the outer layers and tensile stress in the
center orcore.
Catalyst. A substance, usually present in small amounts relative to the
reactants, that modifies the rate of a chemical reaction (such as the
cure of an adhesive) without being consumed in the process.
Cell. A general term for the anatomical units of plant tissue, including
wood fibers, vessel members, and other elements of diverse structure and
function.
Cellulose. The carbohydrate that is the principal constituent of wood
and forms the framework of the wood cells.
Check. A lengthwise separation of the wood that usually extends across
the rings of annual growth and commonly results from stresses set up in
wood during seasoning.
Chemical Brown Stain. (See Stain.)
Chipboard. A paperboard used for many purposes that may or may not have
specifications for strength, color, or other characteristics. It is
normally made from paper stock with a relatively low density in the
thickness of 0.006 inch and up.
Close Grained. (See Grain.)
Coarse Grain. (See Grain.)
Cohesion. The state in which the particles of a single substance are
held together by primary or secondary vaience forces. As used in the
adhesive field, the state in which the par'~cles of adhesive (or
adherend) are held together internally.
Cold Pressing. A bonding operation in which an assembly is subjected to
pressure without the application of heat.
Cold-Press Plywood. (See Plywood.)
Collapse. The flattening of single cells or rows of cells in heal,wood
during the drying or pressure treatment of wood. Often characterized by
a caved-in or corrugated appearance of the wood surface.
Compartment Kiln. (See Kiln.)
Composite Panel. A veneer-faced panel with a reconstituted wood core.
The flakeboard core may be random or have aiignment in the direction 90°
from the grain direction of the veneer faces.
Compound Curvature. Wood bent to a compound curvature has curved
surfaces, no element of which is a straight line.
Compreg. Wood in which the cell wails have been impregnated with
synthetic resin and compressed to give it reduced swelling and shrinking
charactetistics and increased density and strength properties.
Compression Failure. Deformation of the wood fibers resulting from
excessive compression aiong the grain either in direct end compression
or in bending. It may develop in standing trees due to bending by wind
or snow or to internal longitudinai stresses developed in growth, or it
may result
from stresses imposed after the tree is cut. In surfaced lumber,
compression failures may appear as fine wrinkles across the face of the
piece.
Compression Wood. Abnormal wood formed on the lower side of branches and
inclined trunks of softwood trees. Compression wood is identified by its
relatively wide annual tings (usuaily eccentric when viewed on cross
section of branch or trunk), relatively large amount of summerwood,
sometimes more than 50 percent of the width of the annuai tings in which
it occurs, and its lack of demarcation between earlywood and latewood in
the same annual tings. Compression wood shrinks excessively lengthwise,
as compared with normai wood.
Conditioning (pre and pose). The exposure of a materiai to the influence
of a prescribed atmosphere for a stipulated period of time or until a
stipulated relation is reached between matetiai and atmosphere.
Conifer. (See Softwoods. )
Connector, Timber. Metal tings, plates, or grids which are embedded in
the wood of adjacent members, as at the bolted points of a truss, to
increase the strength of the joint.
Consistency. That property of a liquid adhesive by virtue of which it
tends to resist deformation. Note: Consistency is not a fundamental
property but is comprised of rheological properties such as viscosity,
plasticity, and other phenomena.
Construction Adhesive. (See Adhesive.)
Contact Angle. The angle (0) between a substrate plane and the free
surface of a liquid droplet at the line of contact with substrate.
Cooperage. Containers consisting of two round heads and a body composed
of staves held together with hoops, such as barrels and kegs.
Slack Cooperage--Cooperage used as containers for dry, semidry or solid
products. The staves are usually not closely fitted and are held
together with beaded steel, wire, or wood hoops.
Tight Cooperage-Cooperage used as containers for liquids, semisolids,
and heavy solids. Staves are well fitted and held tightly with cooperage
grade steel hoops.
Copolymer. Substance obtained when two or more types of monomers
polymerize.
Corbel. A projection from the face of a wall or column supposing a
weight.
Core Stock. A solid or discontinuous center ply used in panel-type glued
structures (such as furniture panels and solid or hollowcore doors).
Crook. The distortion of lumber in which there is a deviation, in a
direction perpendicular to the edge, from a straight line from end
to-end of the piece.
Crossband. To place the grain of layers of wood at tight angles in order
to minimize shrinking and swelling; also, in plywood of three or more
plies, a layer of veneer whose grain direction is at right angles to
that of the face plies.
Cross Break. A separation of the wood cells across the grain. Such
breaks may be due to internal stress resulting from unequal longitudinal
shrinkage or to external forces.
Cross Grain. (See Grain.)
Cross-Link. An atom or group connecting adjacent molecules in a complex
molecular structure.
Cup. A distortion of a board in which there is a deviation flatwise from
a straight line across the width of the board.
Cure. To change the properties of an adhesive by chemical reaction
(which may be condensation, polymerization, or vulcanization) and
thereby develop maximum strength. Generally accomplished by the action
of heat or a catalyst, with or without pressure.
Curing Agent. (See Hardener.)
Curing Temperature. (See Temperature, Curing.)
Curing Time. (See Time, Curing. )
Curly Grain. (See Grain.)
Curtain Coating. Applying liquid adhesive to adherend by passing the
adherend under a thin curtain of liquid falling by gravity or pressure.
Cut Stock. A term for softwood stock comparable to dimension parts in
hardwoods. (See Dimension Parts.)
Cuttings. In hardwoods, portions of a board or plant having the quality
required by a specific grade or for a particular use. Obtained from a
board by crosscutting or ripping.
Decay. The decomposition of wood substance by fungi.
Advanced (or Typical Decay) The older stage of decay in which the
destruction is readily recognized because the wood has become punky,
soft and spongy, stringy, ringshaked, pitted, or crumbly. Decided
discoloration or bleaching of the rotted wood is often apparent.
Incipient Decay--The early stage of decay that has not proceeded far
enough to soften or otherwise perceptibly impair the hardness of the
wood. It is usually accompanied by a slight discoloration or bleaching
of the wood.
Delamination. The separation of layers in laminated wood or plywood
because of failure of the adhesive, either within the adhesive itself or
at the interface between the adhesive and the adherend.
Delignification. Removal of pal or all of the lignin from wood by
chemical treatment.
Density. As usually applied to wood of normal cellular form, density is
the mass of wood substance enclosed within the boundary surfaces of a
wood plus-voids complex having unit volume. It is variously expressed as
pounds per cubic foot, kilograms per cubic meter, or grams per cubic
centimeter
at a specified moisture content.
Density Rules. A procedure for segregating wood according to density,
based on percentage of latewood and number of growth rings per inch of
radius.
Dew Point. The temperature at which a vapor begins to deposit as a
liquid. Applies especially to water in the atmosphere.
Diagonal Grain. (See Grain.)
Diffuse-Porous Wood. Certain hardwoods in which the pores tend to be
uniform in size and distribution throughout each annual ring or to
decrease in size slightly and gradually toward the outer border of the
ring.
Dimension. (See Lumber.)
Dimension Parts. A term largely superseded by the term "hardwood
dimension lumber." It is hardwood stock processed to a point where the
maximum waste is left at the mill, and the maximum utility is delivered
to the user. It is stock of specified thickness, width, and length, or
multiples thereof. According to specification it may be solid or glued
up, rough or surfaced, semifabricated or completely fabricated.
Dimensional Stabilization. Special treatment of wood to reduce the
swelling and skrinking that is caused by changes in its moisture content
with changes in relative humidity.
Dote. "Dote," "doze," and "rot" are synonymous with "decay" and are any
form of decay that may be evident as either a discoloration or a
softening of the wood.
Double Spread. (See Spread.)
Air-Dried.--Dried by exposure to air in a yard or shed, without
artificial heat.
Klln-Drled.--Dried in a kiln with the use of artificial heat.
Dry-Bulb Temperature. The temperature of air as indicated by a standard
thermometer. (See Psychrometer.)
Dry Kiln. (See Kiln.)
Dry Rot. A term loosely applied to any dry, crumbly rot but especially
to that which, when in an advanced stage, permits the wood to be crushed
easily to a dry powder. The term is actually a misnomer for any decay,
since all fungi require considerable moisture for growth.
Dry Wall. Interior covering material, such as gypsum board, hardboard,
or plywood, which is applied in large sheets or panels.
Durability. A general term for permanence or resistance to
deterioration. Frequently used to refer to the degree of resistance of a
species of wood to attack by wood-destroying fungi under conditions that
favor such attack. In this connection the term "decay resistance" is
more specific. As applied
to bondlines, the life expectancy of the structural qualities of the
adhesive under the anticipated service conditions of the structure.
Earlywood. The portion of the annual growth ring that is formed during
the early pan of the growing season. It is usually less dense and weaker
mechanically than latewood.
Edge Grain. (See Grain.)
Edge Joint. (See Joint.)
Elastomer. A macromolecular material which, at room temperature, is
deformed by application of a relatively low force and is capable of
recovering substantially in size and shape after removal of the force.
Empty-Cell Process. Any process for impregnating wood with preservafives
or chemicals in which air, imprisoned in the wood under pressure,
expands when pressure is released to drive out pal of the injected
preservative or chemical. The distinguishing characteristic of the
empty-cell process is that no vacuum is drawn before applying the
preservative. The aim is to obtain good preservative distribution in the
wood and leave the cell cavities only partially filled.
Encased Knot. (See hot.)
End Grain. (See Grain.)
End Joint. (See Joint.)
Equilibrium Moisture Content. The moisture content at which wood neither
gains nor loses moisture when surrounded by air at a given relative
humidity and temperature.
Excelsior. (See Wood Wool.)
Extender. A substance, generally having some adhesive action, added to
an adhesive to reduce the amount of the primary binder required per unit
area.
Exterior Plywood. (See Plywood.)
Extractive. Substances in wood, not an integral pal of the cellular
structure, that can be removed by solution in hot or cold water, ether,
benzene, or other solvents that do not react chemically with wood
components.
Extrusion Spreading. A method of adhesive application in which adhesive
is forced through small openings in the spreader head.
Factory And Shop Lumber. (See Lumber.)
Failure, Adherend. Rupture of an adhesive joint, such that the
separation appears to be within the adherend.
Failure, Adhesive. Rupture of an adhesive joint, such that the plane of
separation appears to be at the adhesive-adherend interface.
Failure, Cohesive. Rupture of an adhesive joint, such that the
separation appears to be within the adhesive.
Feed Rate. The distance that the stock being processed moves during a
given interval of time or operational cycle.
Fiber, Wood. A wood cell comparatively long (1/25 or less to 1/3 in),
narrow, tapering, and closed at both ends.
Fiberboard. A broad generic term inclusive of sheet materials of widely
varying densities manufactured of refined or partially refined wood (or
other vegetable) fibers. Bonding agents and other materials may be added
to increase strength, resistance to moisture, fire, or decay, or to
improve some other property. (See Medium-Density Fiberboard.)
Fiber Saturation Point. The stage in the drying or wetting of wood at
which the cell walls are saturated and the cell cavities free from
water. It applies to an individual cell or group of cells, not to whole
boards. It is usually taken as approximately 30 percent moisture
content, based on oven dry
weight.
Fibril. A threadlike component of cell walls, visible under a light
microscope.
Fiddleback. (See Grain.)
Figure. The pattern produced in a wood surface by annual growth rings,
rays, knots, deviations from regular grain such as interlocked and wavy
grain, and irregular coloration.
Filler. In woodworking, any substance used to fill the holes and
irregularities in planed or sanded surfaces to decrease the porosity of
the surface before applying finish coatings. As applied to adhesives a
relatively nonadhesive substance added to an adhesive to improve its
working
properties, strength, or other qualities.
Fine Grain. (See Grain.)
Finger Joint. (See Joint. )
Finish (Finishing). Wood products such as doors, stairs, and other fine
work required to complete a building, especially the interior. Also,
coatings of paint, varnish, lacquer, wax, etc., applied to wood surfaces
to protect and enhance their durability or appearance.
Fire Endurance. A measure of the time during which a material or
assembly continues to exhibit fire resistance under specified conditions
of test and performance.
Fire Resistance. The property of a material or assembly to withstand
fire or give protection from it. As applied to elements of buildings, it
is characterized by the ability to confine a fire or to continue to
perform a given structural function, or both.
Fire Retardant. A chemical or preparation of chemicals used to reduce
Flammability or to retard spread of a fire over the surface.
Flake. A small fiat wood particle of predetermined dimensions, uniform
thickness, with fiber direction essentially in the plane of the flake;
in overall character resembling a small piece of veneer. Produced by
special equipment for use in the manufacture of flakeboard.
Flakeboard. (See Particleboard.)
Flame Spread. The propagation of a flame away from the source of
ignition across the surface of a liquid or a solid, or through the
volume of a gaseous mixture.
Flat Grain. (See Grain.)
Flat Sawn. (See Grain.)
Flecks. (See Rays, Wood.)
Flitch. A portion of a log sawn on two or more faces-commonly on
opposite faces leaving two waney edges. When intended for resawing into
lumber, it is resawn parallel to its original wide faces. Or, it may be
sliced or sawn into veneer, in which case the resulting sheets of veneer
laid
together in the sequence of cutting are called a flitch. The term is
loosely used. (See Cant.)
Framing. Lumber used for the structural member of a building, such as
studs and joists.
Full-Cell Process. Any process for impregnating wood with preservatives
or chemicals in which a vacuum is drawn to remove air from the wood
before admitting the preservative. This favors heavy adsorption and
retention of preservative in the treated portions.
Furnish. The wood material which has been reduced for incorporation into
wood-based fiber or particle panel products.
Gap-Filling Adhesive. (See Adhesive,)
Gelatinous Fibers. Modified fibers that are associated with tension wood
in hardwoods.
Girder. A large or principal beam used to support concentrated loads at
isolated points along its length.
Gluability. (See Bondability.)
Glue. Originally, a hard gelatin obtained from hides, tendons,
cartilage, bones, etc., of animals. Also, an adhesive prepared from this
substance by heating with water. Through general use the term is now
synonymous with the term "Adhesive."
Glue Laminating. Production of structural or nonstructural wood members
by bonding two or more layers of wood together with adhesive.
Glueline. (See Bondline.)
Grade. The designation of the quality of a manufactured piece of wood or
of logs.
Grain. The direction, size, arrangement, appearance, or quality of the
fibers in wood or lumber. To have a specific meaning the term must be
qualified.
Close-Grained Wood--Wood with narrow, inconspicuous annual rings. The
term is sometimes used to designate wood having small and closely spaced
pores, but in this sense the term "fine textured" is more often used.
Coarse-Grained Wood--Wood with wide conspicuous annual rings in which
there is considerable difference between springwood and summerwood. The
term is sometimes used to designate wood with large pores, such as oak,
ash, chestnut, and walnut, but in this sense the term "coarse textured"
is more often used.
Cross-Grained Wood--Wood in which the fibers deviate from a line
parallel to the sides of the piece. Cross grain may be either diagonal
or spiral grain or a combination of the two.
Curly-Grained Wood--Wood in which the fibers are distorted so that they
have a curled appearance, as in "birdseye" wood. The areas showing curly
grain may vary up to several inches in diameter.
Diagonal-Grained Wood--Wood in which the annual rings are at an angle
with the axis of a piece as a result of sawing at an angle with the bark
of the tree or log. A form of cross-grain.
Edge-Grained Lumber--Lumber that has been sawed so that the wide
surfaces extend approximately at right angles to the annual growth
rings. Lumber is considered edge grained when the rings form an angle of
45~ to 90° with the wide surface of the piece.
End-Grained Wood--The grain as seen on a cut made at a right angle to
the direction of the fibers (e.g., on a cross section of a tree).
Fiddleback-Grained Wood--Figure produced by a type of fine wavy grain
found, for example, in species of maple; such wood being traditionally
used for the backs of violins.
Fine-Grained Wood- (See Grain.)
Flat-Grained Wood--Lumber that has been sawed parallel to the pith and
approximately tangent to the growth rings. Lumber is considered fiat
grained when the annual growth rings make an angle of less than 45° with
the surface of the piece.
Interlocked-Grained Wood--Grain in which the fibers put on for several
years may slope in a right-handed direction, and then for a number of
years the slope reverses to a left-handed direction, and later changes
back to a right-handed pitch, and so on. Such wood is exceedingly
difficult to split radially, though tangentially it may split fairly
easily.
Open-Grained Wood--Common classification for woods with large pores,
such as oak, ash, chestnut, and walnut. Also known as "coarse textured."
Plainsawn Lumber--Another term for fiat-grained lumber.
Quartersawn Lumber--Another term for edge-grained lumber.
Side-Grained Wood--Another term for fiat-grained lumber.
Slash-Grained Wood--Another term for fiat-grained lumber.
Spiral-Grained Wood--Wood in which the fibers take a spiral come about
the trunk of a tree instead of the normal vertical course. The spiral
may extend in a right-handed or left-handed direction around the tree
trunk. Spiral grain is a form of cross grain.
Straight-Grained Wood--Wood in which the fibers mn parallel to the axis
of a piece.
Vertical-Grained Lumber--Another term for edge-grained lumber.
Wavy-Grained Wood-Wood in which the fibers collectively take the form of
waves or undulations.
Green. Freshly sawed or undried wood. Wood that has become completely
wet after immersion in water would not be considered green, but may be
said to be in the "green condition."
Growth Ring. (See Annual Growth Ring.)
Gum. A comprehensive term for nonvolatile viscous plant exudates, which
either dissolve or swell up in contact with water. Many substances
referred to as gums such as pine and spruce gum are actually oleoresins.
Hardbond. A generic term for a panel manufactured primanly from
interfelted ligno-cellulosic fibers (usually wood), consolidated under
heat and pressure in a hot press to a density of 31 pounds per cubic
foot or greater, and to which other materials may have been added during
manufacture to improve certain properties.
Hardener (noun). A substance or mixture of substances added to an adhe-
sive to promote or control the curing reaction by taking part in it. The
term is also used to designate a substance added to control the degree
of hardness of the cured film. (See Catalyst.)
Hardness. A property of wood that enables it to resist indentation.
Hardwoods. Generally one of the botanical groups of trees that have
broad leaves in contrast to the conifers or softwoods. The term has no
reference to the actual hardness of the wood.
Heart Rot. Any rot characteristically confined to the hemwood. It
generally originates in the living tree.
Heartwood. The wood extending from the pith to the sapwood, the cells of
which no longer participate in the life processes of the tree. Heartwood
may contain phenolic compounds, gums, resins, and other materials that
usually make it darker and more decay resistant than sapwood.
Henricellulose. A celluloselike material (in wood) that is easily
decomposa-
ble as by dilute acid, yielding several different simple sugars.
Hertz. A unit of frequency equal to one cycle per second.
High Frequency Curing. (See Radiofrequency Curing.)
Hollow-Core Construction. A panel construction with faces of plywood,
hardboard, or similar material bonded to a framed-core assembly of wood
lattice, paperboard rings, or the like, which support the facing at
spaced intervals.
I-Ioneycomb Core. A sandwich core material constructed of thin sheet
materials or ribbons formed to honeycomblike configurations.
Honeycombing. Checks, often not visible at the surface, that occur in
the interior of a piece of wood, usually along the wood rays.
Horizontally Laminated Timber. (See Laminated Timbers.)
Hot-Setting Adhesive. (See Adhesive.)
Impreg. Wood in which the cell walls have been impregnated with
synthetic resin so as to reduce materially its swelling and shrinking.
Impreg is not compressed.
Increment Borer. An augerlike instrument with a hollow bit and an
extractor, used to extract thin radial cylinders of wood from trees to
determine age and growth rate. Also used in wood preservation to
determine the depth of penetration of a preservative.
Insulating Board. (See Structurai Insulating Board.)
Intergrown Knot. (See Knot. )
Interlocked-Grained Wood. (See Grain. )
Internai Stresses. Stresses that exist within an adhesive joint even in
the absence of applied external forces.
Interphase. In wood bonding, a region of finite thickness as a gradient
between the bulk adherend and bulk adhesive in which the adhesive
penetrates and alters the adherend's properties and in which the
presence of the adherend influences the chemical and/or physical
properdes of the adhesive.
Intumesce. To expand with heat to provide a low-density film; used in
reference to certain fire-retardant coatings.
Isotropic. Exhibiting the same properties in all directions.
Joint. The junction of two pieces of wood or veneer.
Adhesive Joint--The location at which two adherends are held together
with a layer of adhesive.
Assembly joint--Joints between variously shaped parts or subassemblies
such as in wood furniture (as opposed to joints in plywood and laminates
that are all quite similar).
Butt Joint--An end joint formed by abutting the squared ends of two
pieces.
Edge Joint--A joint made by bonding two pieces of wood together edge to
edge, commonly by gluing. The joints may be made by gluing two squared
edges as in a plain edge joint or by using machined joints of various
kinds, such as tongued-and-grooved joints.
End Joint- A joint made by bonding two pieces of wood together end to
end, commonly by finger or scarf joint.
Finger Joint- An end joint made up of several meshing wedges or fingers
of woed bonded together with an adhesive. Fingers are sloped and may be
cut parallel to either the wide or narrow face of the piece.
Lap Joint- A joint made by placing one member partly over another and
bonding the overlapped portions.
Scarf Joint--An end joint formed by joining with adhesive the ends of
two pieces that have been tapered or beveled to form sloping plane
surfaces, usually to a featheredge, and with the same slope of the plane
with respect to the length in both pieces. In some cases, a step or hook
may be machined into the scarf to facilitate alinement of the two ends,
in which case the plane is discontinuous and the joint is known as a
stepped or hooked scarf joint.
Starved Joint- A glue joint that is poorly bonded because an
insufficient quantity of adhesive remained in the joint.
Sunken Joint--Depression in wood surface at a joint (usually an edge
joint) caused by 'surfacing material too soon after bonding. (Inadequate
time was allowed for moisture added with the adhesive to diffuse away
from the joint.)
Joint Efficiency or Factor. The strength of a joint expressed as a
percentage of the strength of clear straight-grained material.
Joist. One of a series of parallel beams used to support floor and
ceiling loads and supported in turn by larger beams, girders, or beating
walls.
Kiln. A chamber having controlled air-flow, temperature, and relative
humidity for drying lumber, veneer, and other wood products.
Compartment Kiin--A kiln in which the total charge of lumber is dried as
a single unit. It is designed so that, at any given time, the
temperature and relative humidity are essentially uniform throughout the
kiln. The temperature is increased as drying progresses, and the
relative humidity
is adjusted to the needs of the lumber.
Progressive Kiln--A kiln in which the total charge of lumber is not
dried as a single unit but as several units, such as kiln truckloads,
that move progressively through the kiln. The kiln is designed so that
the temperature is lower and the relative humidity higher at the end
where the
lumber enters than at the discharge end.
Kiln Dried. (See Seasoning.)
Knot. That portion of a branch or limb that has been surrounded by
subsequent growth of the stem. The shape of the knot as it appears on a
cut surface depends on the angle of the cut relative to the long axis of
the knot.
Encased Knot- A knot whose rings of annual growth are not intergrown
with those of the surrounding wood.
Intergrown Knot--A knot whose rings of annual growth are completely
intergrown with those of the surrounding wood.
Loose Knot--A knot that is not held froray in place by growth or
position and that cannot be relied upon to remain in place.
Pin Knot--A knot that is not more than 1/2 inch in diameter.
Sound Knot--A knot that is solid across its face, at least as hard as
the surrounding wood, and shows no indication of decay.
Spike Knot--A knot cut approximately parallel to its long axis so that
the exposed section is definitely elongated.
Laminate. A product made by bonding together two or more layers
(laminations) of material or materials.
Laminate, Paper-Base. A multilayered panel made by compressing sheets of
resin-impregnated paper together into a coherent solid mass.
Luminated Timbers. An assembly made by bonding layers of veneer or
lumber with an adhesive so that the grain of all laminations is
essentially parallel. (See Built-Up Timbers.)
Horizontally Luminated Timbers--Laminated timbers designed to resist
bending loads applied perpendicular to the wide faces of the
laminations.
Vertically Laminated Timbers--Laminated timbers designed to resist
bending loads applied parallel to the wide faces of the laminations.
Laminated Veneer Lumber (LVL). A structural lumber manufactured from
veneers laminated into a panel with the grain of all veneer running
parallel to each other. The resulting panel is normally manufactured in
3/4- to 1- I/2-inch thicknesses and ripped to common lumber widths of
1-1/2 to 11-1/2 inches, or wider.
Lap Joint. (See Joint.)
Latewood. The portion of the annual growth ring that is formed after the
earlywood formation has ceased. It is usually denser and stronger
mechanically than earlywood.
Latex Paint. A paint containing pigments and a stable water suspension
of synthetic resins (produced by emulsion polymerization) that forms an
opaque film through coalescence of the resin during water evaporation
and subsequent curing.
Layup. The process of loosely assembling the adhesive-coated components
of a unit, particularly a panel, to be pressed or clamped.
Lbs/MSGL. Abbreviation for rate of adhesive application in pounds of
adhesive per thousand square feet of single glueline (bondline). (See
Spread.) When both faces of an adherend are spread as in some plywood
manufacturing processes, the total weight of adhesive applied may be
expressed as Lbs/MDGL (pounds per 1,0{30 square feet double glueline).
Lignin. The second most abundant constituent of wood, located
principally in the secondary wall and the middle lamella, which is the
thin cementing layer between wood cells. Chemically it is an irregular
polymer of substituted propylphenol groups, and thus no simple chemical
formula can be
written for it.
Longitudinal. Generally, parallel to the direction of the wood fibers.
Loose Knot. (See Knot.)
Lumber. The product of the saw and planing mill not further manufactured
than by sawing, resawing, passing lengthwise through a standard planing
machine, crosscutting to length, and matching.
Boards--Lumber that is nominally less than 2 inches thick and 2 or more
inches wide. Boards less than 6 inches wide are sometimes called strips.
Dimension--Lumber with a nominal thickness of from 2 up to but not
including 5 inches and a nominal width of 2 inches or more.
Dressed Size--The dimensions of lumber after being surfaced with a
planing machine. The dressed size is usually 1/2 to 3/4 inch less than
the nominal or rough size. A 2- by 4-inch stud, for example, actually
measures about l-l/2 by 3-1/2 inches.
Factory and Shop Lumber--Lumber intended to be cut up for use in further
manufacture. It is graded on the basis of the percentage of the area
that will produce a limited number of cuttings of a specified minimum
size and quality.
Matched Lumber--Lumber that is edge dressed and shaped to make a close
tongued-and-grooved joint at the edges or ends when laid edge to edge or
end to end.
Nominal Size--As applied to timber or lumber, the size by which it is
known and sold in the market; often differs from the actual size. (See
Lumber.)
Patterned Lumber--Lumber that is shaped to a pattern or to a molded form
in addition to being dressed, matched, or shiplapped, or any combination
of these workings.
Rough Lumber--Lumber that has not been dressed (surfaced) but which has
been sawed, edged, and trimmed.
Shiplapped Lumber--Lumber that is edge dressed to make a lapped joint.
Shipping-Dry Lumber--Lumber that is partially dried to prevent stain and
mold in transit.
Shop Lumber-See Lumber.)
Side Lumber--A board from the outer portion of the log--ordinarily one
produced when squaring off a log for a tie or timber.
Structural Lumber--Lumber that is intended for use where allowable
properties are required. The grading of structural lumber is based on
the strength or stiffness of the piece as related to anticipated uses.
Surfaced Lumber--Lumber that is dressed by running it through a planer.
Timbers--Lumber that is nominally 5 or more inches in least dimension.
Timbers may be used as beams, stringers, posts, caps, sills, girders,
purlins, etc.
Yard Lumber--A little-used term for lumber of all sizes and patterns
that is intended for general building purposes having no design property
requirements.
Lumen. In wood anatomy, the cell cavity.
Manufacturing Defects. Includes all defects or blemishes that are
produced in manufacturing, such as chipped grain, loosened grain, raised
grain, tom grain, skips in dressing, hit and miss (series of surfaced
areas with skips between them), variation in sawing, ntiscut lumber,
machine bum, machine
gouge, mismatching, and insufficient tongue or groove.
Mastic. A material with adhesive properties, usually used in relatively
thick sections, that can be readily applied by extrusion, trowel, or
spatula. (See Adhesive.)
Matched Lumber. (See Lumber.)
Medium-Density Fiberboard. A panel product manufactured from
ligno-cellulosic fibers combined with a synthetic resin or other
suitable binder. The panels are manufactured to a density of 31 pcf
(0.50 specific gravity) to 55 pcf (0.88 specific gravity) by the
application of heat and pressure by
a process in which the interfiber bond is substantially created by the
added binder. Other materials may have been added during manufacturing
to improve certain properties.
Millwork. Planed and patterned lumber for finish work in buildings,
including items such as sash, doors, cornices, panelwork, and other
items of interior or exterior trim. Does not include flooring, ceiling,
or siding.
Mineral Streak. An olive to greenish-black or brown discoloration of
undetermined cause in hardwoeds.
Modified Wood. Wood processed by chemical treatment, compression, or
other means (with or without heat) to impart properties quite different
from those of the original wood.
Moisture Content. The amount of water contained in the woed, usually
expressed as a percentage of the weight of the ovendry wood.
Moulded Plywood. (See Plywood.)
Moulding. A wood strip having a curved or projecting surface, used for
decorative purposes.
Monomer. A relatively simple molecular compound which can react at more
than one site to form a polymer.
Mortise. A slot cut into a board, plank, or timber, usually edgewise, to
receive the tenon of another board, plank, or timber to form a joint.
Naval Stores. A term applied to the oils, resins, tars, and pitches
derived from oleoresin contained in, exuded by, or extracted from trees,
chiefly species of pines (genus Pinus). Historically, these were
important items in the stores of wood sailing vessels.
Nominal-Size Lumber. (See Lumber.)
Oil Paint. A paint containing a suspension of pigments in an or§anic
solvent and a drying oil, modified drying oil, or synthetic polymer that
forms an opaque film through a combination of solvent evaporation and
curing of the oil or polymer.
Old Growth. Timber in or from a mature, naturally established forest.
When the trees have grown during most if not all of their individual
lives in active competition with their companions for sunlight and
moisture, this timber is usually straight and relatively free of hots.
Oleoresin. A solution of resin in an essential oil that occurs in or
exudes from many plants, especially softwoods. The oleoresin from pine
is a solution of pine resin (rosin) in turpentine.
Open Assembly Time. (See Time, Assembly.)
Open Grain. {See Grain.)
Orthotropic. Having unique and independent properties in three mutually
orthogonal (perpendicular) planes of symmetry. A special case of
anisotropy.
Ovendry Wood. Wood dried to a relatively constant weight in a ventilated
oven at 102 to 105 °C.
Overlay. A thin layer of paper, plastic, film, metal foil, or other
material bonded to one or both faces of panel products or to lumber to
provide a protective or decorative face or a base for painting.
Paint. Any pigmented liquid, liquifiable, or mastic composition designed
for application to a substrate in a thin layer that converts to an
opaque solid film after application.
Pallet. A low wood or metal plafform on which material can be stacked to
facilitate mechanical handling, moving, and storage.
Paperboard. The distinction between paper and paperboard is not sharp,
but broadly speaking, the thicker (over 0.012 in), heavier, and more
rigid grades of paper are called paperboard.
Papreg. Any of various paper products made by impregnating sheets of
specially manufactured high-strength paper with synthetic resin and
laminatin§ the sheets to form a dense, moisture-resistant product.
Parenchyma. Short cells having simple pits and functioning primarily in
the metabolism and storage of plant food materials. They remain alive
longer than the tracheids, fibers, and vessel segments, sometimes for
many years. Two kinds of parenchyma cells are recognized-those in
vertical strands, known more specifically as axial parenchyma, and those
in horizontal series in the rays, known as ray parenchyma.
Particleboard. A generic term for a material manufactured from wood
particles or other ligno-cellulosic material and a synthetic resin or
other suitable binder.
Extruded Particleboard--A particleboard made by ramming binder-coated
particles into a heated die, which subsequently cures the hinder and
forms a rigid mass as the material is moved through the die.
Flakeboard--A particle panel product composed of flakes.
Mat-Formed Particleboard--A particleboard in which the particles (being
previously coated with the bindin§ agent) are formed into a mat having
substantially the same length and width as the finished panel. This mat
is then duly pressed in a heated fiat-platen press to cure the
binding agent.
Mende-Process Boaed---A particleboard made in a continuous ribbon from
wood particles with thermosetting resins used to bond the particles.
Thickness ranges from 1/32 to 1/4 inch.
Multilayer Panicleboard- A type of construction in which the wood
particks are made or classified into different sizes and placed into the
preprocessed panel configuration to produce a panel with specific
propenies. Panels which are destined for primanly nonstructural uses
requiring smooth faces are configured with small particles on the
outside and coatset particles on the interior (core). Panels designed
for structural application may have flakes aligned in orthogonal
directions in various
layers which mimic the structure of plywood. Three- and five-layer
constructions are most common.
Oftented Strand Board--A type of particle panel product composed of
strand-type flakes which are purposefully alined in directions which
make a panel stronger, stiffer, and with improved dimensional properties
in the alinement directions than a panel with random flake orientation.
Waferboard--A pardcle panel product made of wafer-type flakes. Usually
manufactured to possess equal properties in all directions parallel to
the plane of the panel.
Particles. The aggregate component of particleboard manufactured by
mechanical means from wood. These include all small subdivisions of wood
such as chips, curls, flakes, sawdust, shavings, slivers, strands,
wafers, wood flour, and wood wool.
Peck. Pockets or areas of disintegrated wood caused by advanced stages
of localized decay in the living tree. It is usually associated with
cypress and incense-cedar. There is no further development of peck once
the lumber is seasoned.
Peel. To convert a log into veneer by rotary cutting.
Phloem. The tissues of the inner bark, characterized by the presence of
sieve tubos and serving for the transport of elaborate foodstuffs.
Pac. A long, heavy timbor, round or square, that is driven deep into the
ground to provide a secure foundation for structures built on soft, wet,
or submerged sites; e.g., landing stages, bridge abutments.
Pin-Knot. {See Knot.)
Pitch Pocket. An opening extending parallel to the annual growth rings
and containing, or that has contained, pitch, either solid or liquid.
Pitch Streaks. A well-defined accumulation of pitch in a more or less
regular streak in the wood of certain conifers.
Pith. The small, soft core occurring near the center of a tree trunk,
branch, twig, or log.
Pith Fleck. A narrow streak, resembling pith on the surface of a piece;
usually brownish, up to several inches in length; results from burrowing
of larvae in the growing tissues of the tree.
Plainsawed. (See Grain.)
Planing Mill Products. Products worked to pattern, such as flooring,
ceiling, and siding.
Plank. A broad board, usually more than 1 inch thick, laid with its wide
dimension horizontal and used as a beanng surface.
Plasficizing Wood. Softening wood by hot water, steam, or chemical
treatment to increase its moldability.
Plywood. A glued wood panel made up of relatively thin layers of veneer
with the grain of adjacent layers at right angles, or of veneer in
combination with a core of lumber or of reconstituted wood. (See
Composite Panel.) The usual constructions have an odd number of layers.
Cold-Pressed Plywood--Refers to interior-type plywood manufactured in a
press without external applications of heat.
Exterior Plywood--A general term for plywood bonded with a type of
adhesive that by systematic tests and service records has proved highly
resistant to weather; micro-organisms; cold, hot, and boiling water;
steam; and dry heat.
Interior Hywood--A general term for plywood manufactured for indoor use
or in construction subjected to only temporary moisture. The adhesive
used may be interior, intermediate, or exterior.
Marine Plywood--Plywood panels manufactured with the same glueline
durability requirements as other exterior-type panels but with more
restrictive veneer quality requirements.
Molded Plywood--Plywood that is glued to the desired shape either
between curved forms or more commonly by fluid pressure applied with
flexible bags or blankets (bag molding) or other means.
Posfformed Plywoed--The product formed when flat plywood is reshaped
into a curved configuration by steaming or plasticizing agents.
Pocket Rot. Advanced decay that appears in the form of a hole or pocket,
usually surrounded by apparently sound wood.
Polymer. A compound formed by the reaction of simple molecules having
functional groups which permit their combination to proceed to high
molecular weights under suitable conditions. Polymers may be formed by
polymerization (addition polymer) or polycondensation (condensation
poly-
mer). When two or more different monomers are involved, the product is
called a copolymer.
Polymerizatlon. A chemical reaction in which the molecules of a monomer
are linked together to form large molecules whose molecular weight is a
multiple of that of the original substance. When two or more different
monomers are involved, the process is called copolymerization.
Pore. (See Vessels.)
Porous Woods. Hardwoods having vessels or pores large enough to be seen
readily without magnification.
Postformed Plywood. (See Plywood.)
Post Cure (noun). A treatment (normally involving heat) applied to an
adhesive assembly following the initial cure, to complete cure, or to
modify specific properties.
Post Cure (verb). To expose an adhesive assembly to an additional cure,
following the initial cure, to complete cure or to modify specific
properties.
Pot Life. (See Working Life.)
Precure. Condition of too much cure, set, or solvent loss of the
adhesive before pressure is applied, resulting in inadequate flow,
transfer, and bonding.
Preservative. Any substance that, for a reasonable length of time, is
effective in preventing the development and action of wood-rotting
fungi, borers of various kinds, and harmful insects that deteriorate
wood.
Pressure Process. Any process of treating wood in a closed container
where by the preservative or fire retardant is forced into the wood
under pressures greater than 1 atmosphere. Pressure is generally
preceded or fol1owed by vacuum, as in the vacuum-pressure and empty-cell
processes respectively; or they may alternate, as in the full-cell and
alteruating-pressure processes.
Progressive Kiln. (See Kiln.)
Psychrometer. An instrument for measuring the amount of water vapor in
the atmosphere. It has both a dry-bulb and wet-bulb thermometer. The
bulb of the wet-bulb thermometer is kept moistened and is, therefore,
cooled by evaporation to a temperature lower than that shown by the
dry-bulb
thermometer. Because evaporation is greater in dry air, the difference
between the two thermometer readings will be greater when the air is dry
than when it is moist.
Radial. Coincident with a radius from the axis of the tree or log to the
circumference. A radial section is a lengthwise section in a plane that
passes through the centerline of the tree trunk.
Radiofrequency (RF) Curing. Curing of bondlines by the application of
radiofrequency. energy. (Sometimes called high-frequency curing.)
Rafter. One of a series of structural members of a roof designed to
support roof loads. The rafters of a flat roof are sometimes called roof
joists.
Raised Grain. A roughened condition of the surface of dressed lumber in
which the hard latewood is raised above the softer earlywood but not tom
loose from it.
Rays, Wood. Strips of cells extending radially within a tree and varying
in height from a few cells in some species to 4 or more inches in oak.
The rays serve primarily to store food and transport it horizontally in
the tree. On quartersawed oak, the rays form a conspicuous figure,
sometimes re-
ferred to as flecks.
Reaction Wood. Wood with more or less distinctive anatomical characters,
formed typically in parts of leaning or crooked stems and in branches.
In hardwoods, this consists of tension wood and in softwoods of
compression wood.
Relative Humidity. Ratio of the amount of water vapor present in the air
to that which the air would hold at saturation at the same temperature.
It is usually considered on the basis of the weight of the vapor but,
for accuracy, should be considered on the basis of vapor pressures.
Resilience. The property whereby a strained body gives up its stored
energy on the removal of the deforming force.
Resin. Inflammable, water-soluble, vegetable substances secreted by
certain plants or trees, and characterizing the wood of many coniferous
species. The term is also applied to synthetic organic products related
to the natural resins.
Resin Ducts. Intercellular passages that contain and transmit resinous
materials. On a cut surface, they are usually inconspicuous. They may
extend vertically parallel to the axis of the tree or at tight angles to
the axis and parallel to the rays.
Retention by Assay. The determination of preservative retention in a
specific zone of treated wood by extraction or analysis of specified
samples.
Rheology. The study of the deformation and flow of matter.
Ring Failure. A separation of the wood during seasoning, occurnng along
the grain and parallel to the growth rings. (See SHAKE.)
Ring-Porous Woods. A group of hardwoods in which the pores are
comparatively large at the beginning of each annual ring and decrease in
size more or less abruptly toward the outer portion of the ting, thus
forming a distinct inner zone of pores, known as the earlywood, and an
outer zone
with smaller pores, known as the latewood.
Ring Shake. (See Shake.)
Rip. To cut lengthwise, parallel to the grain.
Roll Spreading. Application of a film of a liquid material to a surface
by means of rollers.
Room-Temperature-Setting Adhesive. (See Adhesive.)
Rot. (See Decay.)
Rotary-Cut Veneer. (See Veneer.)
Rough Lumber. (See Lumber.)
Sandwich Construction. (See Structural Sandwich Construction.)
Sap Stain. (See Stain.)
Sapwood. The wood of pale color near the outside of the log. Under most
conditions the sapwood is more susceptible to decay than heartwood.
Sash. A frame structure, normally glazed (e. g., a window), that is hung
or fixed in a frame set in an opening.
Sawed Veneer. (See Veneer.)
Saw Kerr. (1) Grooves or notches made in cutting with a saw; (2) that
portion of a log, timber, or other piece of wood removed by the saw in
parting the material into two pieces.
Scarf Joint. (See Joint.)
Schedule, Kiln Drying. A prescribed series of dry- and wet-bulb
temperatures and air velocities used in drying a kiln charge of lumber
or other wood products.
Seasoning. Removing moisture from green wood to improve its
serviceability.
Second Growth. Timber that has grown after the removal, whether by
cutting, fire, wind, or other agency, of all or a large part of the
previous stand.
Semitransparent Stain. A suspension of pigments in either a drying
oil/organic solvent mixure or a water/polymer emulsion, designed to
color and protect wood surfaces by penetration without forming a surface
film, and without hiding wood grain.
Set. A permanent or semipermanent deformation. In reference to
adhesives, to convert an adhesive into a fixed or hardened state by
chemical or physical action, such as condensation, polymerization,
oxidation, vulcanization, gelation, hydration, or evaporation of
volatile constituents.
Shake. A separation along the grain, the greater part of which occurs
between the rings of annual growth. Usually considered to have occurred
in the standing tree or during felling.
Shakes. In construction, shakes are a type of shingle usually hand cleft
from a belt and used for roofing or weatherboarding.
Shaving. A small wood particle of indefinite dimensions developed
incidental to certain woodworking operations involving rotary
cutterbeads usually taming in the direction of the grain. This cutting
action produces a thin chip of varying thickness, usually leathered
along at least one edge and thick at another and generally curled.
Shear. A condition of stress or strain where parallel planes slide
relative to one another.
Sheathing. The structural covering, usually of boards, building
fiberboards, or plywood, placed over exterior studding or rafters of a
structure.
Shelf Life. (See Storage Life.)
Shiplapped Lumber. (See Lumber.)
Shipping-Dry Lumber. (See Lumber.)
Shop Lumber. (See Lumber.)
Side-Grained. (See Grain. )
Side Lumber. (See Lumber.)
Siding. The finish covering of the outside wall of a frame building,
whether made of horizontal weatherboards, vertical boards with battens,
shingles, or other material.
Slash-Grained. (See Grain.)
Sliced Veneer. (See Veneer.)
Soft Rot. A special type of decay developing under very wet conditions
(as in cooling towers and boat timbers) in the outer wood layers, caused
by cellulose-destroying microfungi that attack the secondary cell walls
and not the intercellular layer.
Softwoods. Generally, one of the botanical groups of trees that in most
cases have needlelike or scalelike leaves, the conifers, also the wood
produced by such trees. The term has no reference to the actual hardness
of the wood.
Solid Color Stains (Opaque Stains). A suspension of pigments in either a
drying oil/organic solvent mixture or a water/polymer emulsion designed
to color and protect a wood surface by forming a film. Solid color
stains are similar to paints in application techniques and in
performance.
Solids Content. The percentage of weight of the nonvolatile matter in an
adhesive.
Solvent Adhesive. (See Adhesive.)
Sound Knot. (See Knot.)
Specific Gravity. As applied to wood, the ratio of the ovendry weight of
a sample to the weight of a volume of water equal to the volume of the
sample at a specified moisture content (green, air-dry, or ovendry).
Spike Knot. (See Knot.)
Spiral Grain. (See Grain.)
Spread. The quantity of adhesive per unit joint area applied to an
adherend, usually expressed in pounds of adhesive per thousand square
feet of joint area. (See Lbs/MSGL.)
Single spread---Refers to application of adhesive to only one adherend
of a joint.
Double spread--Refers to application of adhesive to both adherends of a
joint.
Springwood. (See Earlywood.)
Squeezeout. Bead of adhesive squeezed out of a joint when pressure is
applied.
Stain. A discoloration in wood that may be caused by such diverse
agencies as micro-organisms, metal, or chemicals. The term also applies
to materials used to impart color to wood.
Blue Stain- A bluish or grayish discoloration of the sapwood caused by
the growth of certain dark-colored fungi on the surface and in the
interior of the wood; made possible by the same conditions that favor
the growth of other fungi.
Brown Stain--A rich brown to deep chocolate-brown discoloration of the
sapwood of some pines caused by a fungus that acts much like the
blue-stain fungi.
Chemical Brown Stain--A chemical discoloration of wood, which sometimes
occurs during the air drying or kiln drying of several species,
apparently caused by the concentration and modification of extractives.
Sap Stain (See Stain.)
Sticker Stain--A brown or blue stain that develops in seasoning lumber
where it has been in contact with the stickers.
Starved Joint. (See Joint.)
Static Bending. Bending under a constant or slowly applied load;
flexure.
Staypak. Wood that is compressed in its natural state (that is, without
resin or other chemical treatment) under controlled conditions of
moisture, temperature, and pressure that practically eliminate
springback or recovery from compression. The product has increased
density and strength
characteristics.
Stickers. Strips or boards used to separate the layers of lumber in a
pile and thus improve air circulation.
Sticker Stain. (See Stain. )
Storage Life. The period of time during which a packaged adhesive can be
stored under specific temperature conditions and remain suitable for
use. Sometimes called shelf life.
Straight Grained. (See Grain.)
Strength. (1) The ability of a member to sustain stress without failure.
(2) In a specific mode of test, the maximum stress sustained by a member
loaded to failure.
Strength Ratio. The hypothetical ratio of the strength of a structural
member to that which it would have if it contained no strength-reducing
characteristics (knots, slope-of-grain, shake, etc).
Strass-Wave Timing. A method of measuring the apparent stiffness of a
material by measuring the speed of an induced compression stress as it
propagates through the material.
Stressed-Skin Construction. A construction in which panels are separated
from one another by a central partition of spaced strips with the whole
assembly bonded so that it acts as a unit when loaded.
Stringer. A timber or other support for cross members in floors or
ceilings. In stairs, the support on which the stair treads rest.
Structural Insulating Board. A generic term for a homogeneous panel made
from lignocellulosic fibers (usually wood or cane) characterized by an
integral bond produced by interfelting of the fibers, to which other
materials may have been added during manufacture to improve certain
properties, but which has not been consolidated under heat and pressure
as a separate stage in manufacture, said board having a density of less
than 31 pcf (specific gravity 0.50) but having a density of more than 10
pcf (specific gravity O. 16).
Structural Lumber. (See Lumber.)
Structural Sandwich Construction. A layered construction comprising a
combination of relatively high-strength facing materials intimately
bonded to and acting integrally with a low-density core material.
Structural Timbers. Pieces of wood of relatively large size, the
strength or stiffness of which is the controlling element in their
selection and use. Examples of structural timbers are trestle timbers
(stringers, caps, posts, sills, bracing, bridge ties, guardrails); car
timbers (car framing, including
upper framing, car sills); framing for building (posts, sills, girders);
ship timber (ship timbers, ship decking); and crossarms for poles.
Stud. One of a series of slender wood structural members used as
supporting elements in walls and partitions.
Substrate. A material upon the surface of which an adhesive-containing
substance is spread for any purpose, such as bonding or coating. A
broader term than adherend. (See Adherend.)
Summerwood. (See Latewood.)
Surfaced Lumber. (See Lumber.)
Symmetrical Construction. Plywood panels in which the plies on one side
of a center ply or core are essentially equal in thickness, grain
direction, properties, and arrangement to those on the other side of the
core.
Tack. The property of an adhesive that enables it to form a bond of
measurable strength immediately after adhesive and adherend are brought
into contact under low pressure.
Tangential. Strictly, coincident with a tangent at the circumference of
a tree or log, or parallel to such a tangent. In practice, however, it
often means roughly coincident with a growth ring. A tangential section
is a 1ongitudinal section through a tree or limb perpendicular to a
radius. Flat-grained lumber is sawed tangentially.
Temperature, Curing. The temperature to which an adhesive or an assembly
is subjected to cure the adhesive. Note: The temperature attained by the
adhesive in the process of curing (adhesive curing temperature) may
differ from the temperature of the atmosphere surrounding the assembly
(assembly curing temperature).
Temperature, Setting. (See Temperature, Curing.)
Tenon. A projecting member left by cutting away the wood around it for
insertion into a mortise to make a joint.
Tension Wood. Abnormal wood found in leaning trees of some hardwood
species and characterized by the presence of gelatinous fibers and
excessive longitudinal shrinkage. Tension wood fibers hold together
tenaciously, so that sawed surfaces usually have projecting fibers, and
planed surfaces
often are torn or have raised grain. Tension wood may cause warping.
Texture. A term often used interchangeably with grain. Sometimes used to
combine the concepts of density and degree of contrast between earlywood
and latewood. In this handbook, texture refers to the finer structure of
the wood (see Grain) rather than the annual rings.
Thermoplastic Glues And Resins. Glues and resins that are capable of
being repeatedly softened by heat and hardened by cooling.
Thermosetting Glues And Resins. Glues and resins that are cured with
heat but do not soften when subsequently subjected to high temperatures.
Timbers, Round. Timbers used in the original round form, such as poles,
piling, posts, and mine timbers.
Timber, Standing. Timber still on the stump.
Timbers. (See Lumber.)
Time, Assembly. The time interval between the spreading of the adhesive
on the adherend and the application of pressure or heat, or both, to the
assembly. Note: For assemblies involving multiple layers or parts, the
assembly time begins with the spreading of the adhesive on the first
adherend.
Open Assembly Time-The time interval between the spreading of the
adhesive on the adherend and the completion of assembly of the parts for
bonding.
Closed Assembly Time--The time interval between completion of assembly
of the parts for bonding and the application of pressure or heat, or
both, to the assembly.
Time, Curing. The period of time during which an assembly is subjected
to heat or pressure, or both, to cure the adhesive.
Time, Setting. (See Time, Curing.)
Toughness. A quality of wood which permits the material to absorb a
relatively large amount of energy, to withstand repeated shocks, and to
undergo considerable deformation before breaking.
Tracheid. The elongated cells that constitute the greater part of the
structure of the softwoods (frequently referred to as fibers). Also
present in some hardwoods.
Transfer. In wood bonding, the shanng of adhesive between a spread and
an unspread surface when the two adherends are brought into contact.
Transverse. Directions in wood at right angles to the wood fibers.
Includes radial and tangential directions. A transverse section is a
section through a tree or timber at right angles to the pith.
Treenail. A wooden pin, peg, or spike used chiefly for fastening
planking and ceiling to a framework.
Trim. The finish materials in a building, such as moldings, applied
around openings (window trim, door trim) or at the floor and ceiling of
rooms (baseboard, cornice, and other moldings).
Truss. An assembly of members, such as beams, bars, rods, and the like,
so combined as to form a rigid framework. All members are interconnected
to form triangles.
Twist. A distortion caused by the turning or winding of the edges of a
board so that the four corners of any face are no longer in the same
plane.
Tyloses. Masses of parenchyma cells appearing somewhat like froth in the
pores of some hardwoods, notably the white oaks and black locust.
Tyloses are formed by the extension of the cell wall of the living cells
surrounding vessels of hardwood.
Ultrasoulcs. (See Stress-Wave Timing.)
Vapor Retarder. A material with a high resistance to vapor movement,
such as foil, plastic film, or specially coated paper, that is used in
combination with insulation to control condensation.
Veneer. A thin layer or sheet of wood.
Rotary-Cut Veneer--Veneer cut in a lathe which rotates a log or bolt,
chucked in the center, against a knife.
Sawed Veneer--Veneer produced by sawing.
Sliced Veneer--Veneer that is sliced off a log, bolt, or flitch with a
knife.
Vertical Grain. (See Grain.)
Vertically Laminated Timbers. (See Laminated Timbers.)
Vessels. Wood cells of comparatively large diameter that have open ends
and are set one above the other to form continuous tubes. The openings
of the vessels on the surface of a piece of wood are usually referred to
as pores.
Virgin Growth. The growth of mature trees in the original forests.
Viscoelasticity. The ability of a material to simultaneously exhibit
viscous and elastic responses to deformation.
Viscosity. The ratio of the shear stress existing between laminae of
moving fluid and the rate of shear between these laminae.
Wane. Bark or lack of wood from any cause on edge or corner of a piece
except for eased edges.
Warp. Any variation from a true or plane surface. Warp includes bow,
crook, cup, and twist, or any combination thereof.
Water Repellent. A liquid that penetrates wood which, after drying,
materially retards changes in moisture content and in dimensions without
adversely altering the desirable properties of wood.
Water-Repellent Preservative. A water repellent that contains a
preservative which, after application to wood and drying, accomplishes
the dual purpose of imparting resistance to attack by fungi or insects
and also retards changes in moisture content.
Weathering. The mechanical or chemical disintegration and discoloration
of the surface of wood caused by exposure to light, the action of dust
and sand carried by winds, and the alternate shrinking and swelling of
the surface fibers with the continual variation in moisture content
brought by changes in the weather. Weathering does not include decay.
Wet-Bulb Temperature. The temperature indicated by the wet-bulb
thermometer of a psychrometer.
Wettability. A condition of a surface that determines how fast a liquid
will wet and spread on the surface or if it will be repelled and not
spread on the surface.
White-Rot. In wood, any decay or rot attacking both the cellulose and
the lignin, producing a generally whitish residue that may be spongy or
stringy rot, or occur as pocket rot.
Witness point- A point of a vibrating string of which a
non-vibrational anomaly or node has been created at a point where the
string anchors, passes over, or terminates.
Wire-Wrap Construction- A method of constructing integrated
circuits in which wires are used to connect two points with junction
and terminals; created by wrapping wire around those stakes instead of
soldering to thru-holes.
Wood Failure. The rupturing of wood fibers in strength tests of bonded
joints usually expressed as the percentage of the total area involved
which shows such failure. (See Failure, Adherend.)
Wood Flour. Wood reduced to finely divided particles approximately those
of cereal flours in size, appearance, and texture, and passing a 40-100
mesh screen.
Wood Substance. The solid material of which wood is composed. It usually
refers to the extractive-free solid substance of which the cell walls
are composed, but this is not always true. There is no wide variation in
chemical composition or specific gravity between the wood substance of
various species, the characteristic differences of species being largely
due to differences in extractives, and variations in relative amounts of
cell walls and cell cavities.
Wood Wool. Long, curly, slender strands of wood used as an aggregate
component for some particleboards.
Workability. The degree of ease and smoothness of cut obtainable with
hand or machine tools.
Working Life. The period of time during which an adhesive, after mixing
with catalyst, solvent, or other compounding ingredients, remains
suitable for use. Also called pot life.
Working Properties. The properties of an adhesive that affect or dictate
the manner of application to the adherends to be bonded and the assembly
of the joint before pressure application, i.e. viscosity, pot life,
assembly time, setting time, etc.
Xanthine. A yellow non-water-soluble pigment found in yellow plants and used as one of the dyeing agents in aniline dyes.
Xylem. The portion of the tree trunk, branches, and roots that lies
between the pith and the cambium.
No glossary terms in the Y catagory.
No glossary terms in the Z catagory.