• A
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• E
• F
• G
• H
• I
• J
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• O
• P
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• R
• S
• T
• U
• V
• W
• X
• Y
• Z

A

Abrasion resistance

Resistance to wearing from a mechanical action on a surface.

Abrasive Planer

A planer in which wood is removed by large sandpaper belts

ABS

Acrylonitrile Butadiene Styrene Resin. A high impact resistant plastic, good low and high temperature resistance, bonds well with many adhesive types.

Accelerated aging

A set of laboratory conditions designed to speed up the results of normal aging. Parameters included are temperature, light, oxygen and water. In recent years, the adhesives industry has come to rely more upon the “oxygen bomb” test to indicate the relative life expectancy of an adhesive.

Accelerator

Usually the second part of an adhesive formulation added just before application. It speeds up the curing process.

Accelerator (also see Catalyst)

Usually part B of an adhesive formula; it speeds up the curing process.

Acetone

A very volatile and flammable solvent that is very good for cleaning metal substrates.

Acrylic

A semi-rigid, two-part adhesive that bonds to a large variety of substrates. Acrylics have very good environmental resistance, fast setting speeds and flame retardant properties.

Activator

Chemicals that can be applied directly to a surface or mixed with an adhesive to speed up the setting time. Normally used in small proportions to increase the effectiveness of an accelerator.

Adhere

To cause two surfaces to be held together by adhesion.

Adhered

A body that is held to another body by an adhesive.

Adhesion

The bonding forces between two different materials (e.g. between an adhesive and substrate). Two main types of adhesion are explained below, mechanical and specific. See also Cohesion.

Adhesion Promoter

Material used to improve adhesion between materials. May be used in two different modes: by pre-treatment of a substrate, and as a component in adhesive formulation capable of enhancing adhesion durability due to the improvement in substrate wetting and formation of chemical bonds across the film/substrate interface.

Adhesion, mechanical

Adhesion between surfaces in which the adhesive holds the parts together by an interlocking action. E.G. Adhesive absorbed into the fibres of a paper based material.

Adhesion, specific

Adhesion between surfaces that are held together by valence (electronic) forces of the same type as those which give rise to cohesion.

Adhesive

Material that can be used to adhere or stick one surface to another. (see Adhesion)

Adhesive Failure

Loss of adhesion between the adhesive and substrate. The adhesive pulls cleanly away from the substrate.

Adhesive Tensile Strength

The tensile strength of a bond is the maximum tensile load per unit area, required to break the bond expressed in pounds per square inch. The load is applied at a right angle to the plane of the adhesive.

Adhesive, assembly

An adhesive that can be used for bonding parts together such as the manufacture of a boat, airplane, furniture, and the like.

Adhesive, cold-setting

An adhesive that sets at temperature below 20°C. Not to be confused with Low / Cool Melt Hot Melt Adhesives

Adhesive, contact

An adhesive that is dry to the touch and which will bond to itself instantly on contact; also called contact bond adhesive or dry bond adhesive.

Adhesive, dispersion

A two-phase system in which one phase is suspended in a liquid.

Adhesive, foamed

An adhesive, the apparent density of which has been decreased substantially by the presence of numerous gaseous cells dispersed throughout its mass. Same as cellular adhesive.

Adhesive, heat activated

A dry adhesive film that is rendered tacky or fluid by application of heat or heat and pressure to the assembly.

Adhesive, hot melt

An adhesive that is applied in a molten state and forms a bond on cooling to a solid state.

Adhesive, hot-setting

An adhesive that requires a temperature at or above 100°C to set.

Adhesive, intermediate temperature setting

An adhesive that sets in the temperature range of 31°- 99°C.

Adhesive, pressure sensitive

A visco-elastic material that in solvent-free form remains permanently tacky. Such a material will adhere instantly to most solid surface using very slight pressure.

Adhesive, room temperature setting

An adhesive that sets in the temperature range of 20°-30°C (68°-86°F).

Adhesive, separate application

A 2 part adhesive, one part applied to one substrate and the other part to the other substrate and the two brought together to form a joint.

Adhesive, solvent

An adhesive having a volatile organic liquid as a carrier (thinner).

Adhesive, solvent activated

A dry adhesive film that is rendered tacky just prior to use by application of a solvent.

Aerobic

An epoxy that requires exposure to oxygen to cure.

Aging

The progressive change in the chemical and physical properties of an adhesive.

Aliphatic resin glue

Yellow glues, which offer higher tack for shorter press times, and offer better water resistance and heat resistance than traditional white glues.

Alligatoring

Cracking of a surface into segments so that it resembles the skin of an alligator.

Ambient

The normal surrounding conditions.

Ambient temperature

Temperature of the surrounding air.

Anaerobic

Adhesive that cures in the absence of oxygen. Designed for locking screws, nuts, and bolts etc.

Antioxidants

Compounds that slow down the rate of oxidation of a polymer.

Aqueous

Made with water.

Assembly

A group of materials or parts, including adhesive, which has been placed together for bonding or which has already been bonded together.

Assembly Time

The time period from the application of adhesive until the final application of pressure. This term includes both Closed and Open Assembly Times.

A-stage

An early stage in the reaction of certain thermosetting resins in which the material is fusible and still soluble in certain liquids. See B & C-stages

ASTM

American Society for Testing and Materials.

Auto Tune

A circuit installed in a RF generator designed to maintain the optimum amount of power during a RF cure cycle.

B

Backer

A material bonded to the opposite (back) side of a panel to ensure dimensional stability.

Balanced Construction

A plywood construction in which construction on one side of the panel is similar or identical to the other side.

BASA

British Adhesives & Sealant Association

Blank

The name of the rough end product. Rectangular in shape, they go to the finish machine room. These parts come from specified width ripping. Sometimes called solid parts.

Blocking

Adhesion between touching layers of materials when moderate pressure is applied during storage or use. This is not normally wanted.

Bond

Same as adhere

Bond face

The part or surface of a material that serves as a substrate for an adhesive.

Bond Line

The gap between two substrates that contains the adhesive.

Bond Strength

The unit load that is required to break an adhesive assembly with failure occurring in or near the plane of the bond. This can be affected differently depending upon the speed and direction of the load applied.

B-stage

An intermediate stage in the reaction of certain thermosetting resins in which the material softens when heated and swells when in contact with certain liquids, but may not entirely fuse or dissolve. The resin in an uncured thermosetting adhesive is usually in this stage. See A & C-stages

C

Catalyst (also see Accelerator)

A substance that initiates or speeds up a chemical reaction. Usually part B of a two-part adhesive system.

Cellular material

A material containing many small cells dispersed throughout it. The cells may be either open or closed.

Centipoises (cPs)

A measure of viscosity (water has a cPs of 1), also equivalent to milli-pascals per second (mPas). Other examples for comparison – Blood 10 cps, Heinz Tomato Ketchup 50,000 – 70,000cps and Window Putty 100,000,000cps

Chalking

Chalk-white appearance of a layer of adhesive that has dried too cold. An adhesive which dries below this critical “chalk point” does not fuse together properly and the resulting bond is likely to fail. Normally associated with emulsion adhesives.

Checking

Slight cracks in the surface of an adhesive.

Chemical cure

Curing by chemical reaction, normally involving the cross-linking of a polymer.

Clamp Carrier

A series of clamps arranged and used like a Ferris wheel. This allows large number of panels to be clamped and stored within a small area.

Clamp Time (press time)

The period of time required for a joint to gain enough strength to permit it to be removed from pressure with no decrease in long-term strength.

Clamping Force

The force exerted by a clamping device over a glue line.

Closed Assembly Time

Period of assembly time when the adhesive film is not exposed to the air (when the second substrate is in contact), but before the time that pressure is applied.

Closed cell

A cell enclosed by its walls and therefore not connected to other cells.

Cohesion

The molecular attraction that holds the body of an adhesive together. The internal strength of an adhesive.

Cohesive Failure

Loss of adhesion as a result of the adhesive splitting apart, leaving adhesive on both substrates involved in the bond.

Cohesive strength

The ability of the adhesive to stick within itself during the wet stage. The term cohesive strength also applies to the internal strength of dried adhesive.

Cold Press

A hydraulic or pneumatic press designed to press face-glued or veneered panels without the addition of heat.

Cold pressing

A bonding operation in which an assembly is subjected to pressure without the application of heat.

Combustible

Materials that will burn.

Composite

A combination composed of two or more different materials.

Compression strength

An object’s resistance to rupture under inward pressure.

Compression time

The amount of time required to hold the bond while the hot melt adhesive cures. Compression is very important in achieving good bonds with hot melt adhesives.

Crazing

Fine cracks that may extend in a network on or under the surface of or through a layer of adhesive.

Creep

The deformation of a material with time under constant load.

Crossband

A veneer oriented at right angles to a face veneer in order to ensure dimensional stability in a plywood panel

C-stage

The final stage in the reaction of certain thermosetting resins in which the material is relatively insoluble and infusible. Certain thermosetting resins in a fully cured adhesive layer are in this stage. See A & C-stages

Cure

To set up or harden by means of a chemical reaction.

Cure Cycle

The period of time that an adhesive is being cured in a radio frequency press.

Cure Inhibition

A poisoning of the catalyst in an addition cure product, such that there is a lack of a complete cure, usually at the interface of the adhesive and the other material.

Cure time

Time required to affect a complete cure at a given temperature.

Curing agent

A chemical that is added to affect a cure in a polymer. See Hardener.

Curing time

The time required to cure or “set” an adhesive.

Cyanoacrylate

Known as Super-Glue, a one-part adhesive that cures instantly on contact with mated surfaces. High strength, excellent adhesion to a wide variety of substrates, especially plastics.

D

Delamination

The separation of layers in a laminate because of failure of the adhesive, either in the adhesive itself or at the interface between the adhesive and the substrate, or because of cohesive failure of the substrate.

Degradation

A change in the chemical structure of a hot melt adhesive, demonstrated by damage to its appearance or physical properties.

Density

Ratio of weight (mass) to volume of a material- i.e. grams per cubic centimetre or pounds per gallon. Also called See Specific Gravity

Dilatant Fluid

A fluid whose viscosity increases with increased shear rate- the opposite of thixotropic.

Diluent

An ingredient added to dilute an adhesive that reduces the concentration of bonding materials.

Doctor (bar or blade)

Device that controls the amount of adhesive applied.

Dowel

A cylindrical pin used to reinforce the strength of an assembly joint.

Durometer

A device used to determine the hardness of a material.

Durometer Hardness

A measure of the hardness of a material as measured by a durometer. The resultant numerical rating of hardness in Shore A softer material (30 or 40) to higher numbered, harder material (80 to 90).

Dwell Cycle

The period of time after a panel has been cured in a radio frequency press, but before pressure is released to allow further curing and equalizing.

E

Elasticity

The ability of a material to return to its original shape after removal of a load.

Elastomer

A rubbery material that returns to approximately its original dimensions in a short time after a relatively large amount of deformation.

Elongation

The amount a material will stretch before breaking. Normally expressed as a percentage of its original length.

Emulsion

A dispersion of fine particles in water.

Encapsulate (also see Potting)

The enclosure of an object in an adhesive. Often used in the electronics industry to protect components.

Epoxy

A two-component structural adhesive with high strength and low shrinkage during cure. Epoxies are tough and known for their resistance to chemical and environmental damage.

Equilibrium Moisture Content

The moisture content eventually attained in wood exposed to a given level of relative humidity and temperature.

Ethylene vinyl acetate

(also known as EVA) is the copolymer of ethylene and vinyl acetate. The weight percent vinyl acetate usually varies from 10 to 40%, with the remainder being ethylene

Evaporation Rate

The rate at which a material will vaporize compared with a known substance.

Exothermic

A chemical reaction that gives off heat.

F

Film Tension

The greatest longitudinal stress a cast film (125 mils thickness) can bear without tearing apart.

Finished Dimension

The dimension of a furniture part after it has been machined to its final size either by a moulder or a trim operation in the rough end.

Fixture Time

The time at which an adhesive will hold a part in place. Fixture time is application specific and varies greatly depending on such parameters as part size and configuration, part weight, the particular adhesive used, thickness, temperature and relative humidity.

Flammable

Describes any material that will ignite easily and burn rapidly.

Flash point

The lowest temperature at which the vapours given off by a substance can be ignited.

Flat Sawn

Grain orientation in wood in which annual rings are approximately parallel to the wide surface. Also called Tangential or Plain Sawn.

Flow

Movement of an adhesive during the bonding process before the adhesive sets.

Freeze/thaw stability

The ability of a product to maintain its qualities after it has been frozen and then thawed out.

FRP

Fibreglass Reinforced Plastic.

G

Gel

The state of an adhesive as it hardens from liquid to solid. More often a solid than a liquid.

Gel Time

The time taken by a specific quantity of mixed resin and hardener to become unworkable.

Glass Transition

The reversible change in a substance from a pliable, rubbery condition to a relatively hard and brittle condition or vice-versa.

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 Backup

Occurs when an operator attempts to extrude adhesive from a glue gun before it has reached the correct molten temperature. The adhesive which has cooled in the nozzle has not reached molten temperature. Consequently adhesive is forced back along the barrel through the gap between the adhesive and the barrel wall by trigger pressure. Can cause serious burns!

Glue line

The layer of adhesive that bonds two substrates.

Glue Reel

A series cold clamps arranged and used like a Ferris wheel. This permits a large number of panels to be clamped and stored within a small area.

Green strength

This refers to the relative cohesive strength an adhesive in the wet state. Same as green grab or initial tack. See also tack.

Gum

A substance either exuded by or prepared from plants, tacky when moist, composed of complex carbohydrates and organic acids, which are soluble or swell in water.

H

Hardener

A substance or mixture of substances added to an adhesive to promote or control the curing reaction by taking part in it. It can also denote a material used to alter the degree of hardness of the cured system. Same as curing agent. See also catalyst.

Hardness

A material’s resistance to indentation, scratching or cutting.

Hardwood

Wood from deciduous trees (i.e. oak, maple, cherry, etc.)

Heat Resistance

The temperature at which a bond subjected to a load fails.

Hollow Joints

A machine problem caused by poor alignment of the feed rollers in the head of the straight-line rip. The joint is unable to fit intimately, even when sufficient pressure is applied to the glue joint.

Hot Press

A laminating or veneering press in which the panel assembly is placed between heated platens.

Hot Tack

The holding power of hot-melt adhesives while in the liquid hot state.

Humectant

A hygroscopic substance added to a water-based adhesive to slow the loss of moisture and therefore extend the drying time.

Hydrolysis

Decomposition of a substrate by reaction with water.

Hygroscopic

The ability to absorb and retain atmospheric moisture.

I

Impact Strength

The ability of a material to withstand a shock load.

Inflammable

Capable of being easily set on fire and burning violently.

Inhibitor

A substance that slows down a chemical reaction to prolong storage or working life.

Interface

The common boundary surface between two substances.

IR Pyrometer

A device designed to measure surface temperature by Infrared emissions.

J

J Roller

A hand roller used to apply pressure on a bonded surface such as a plastic laminate.

Joint

The location at which two substrates are held together with a layer of adhesive.

Joint, lap

A joint made by placing one substrate partly over another and bonding together the overlapped area.

Joint, scarf

A joint made by cutting away similar shaped segments out of two materials and then bonding them with the cut areas slotted together.

Joint, starved

A joint that has an insufficient amount of adhesive to produce a good bond.

L

Laminate, (noun)

A product made by bonding together two or more layers of materials.

Laminate, (verb)

To bond layers of material with adhesive.

Laminated, cross

A laminate in which some of the layers are at right angles to the remaining layers with respect to the grain or strongest direction in tension.

Laminated, parallel

A laminate in which all of the layers are oriented parallel with respect to the grain or strongest direction in tension.

Lap Shear

Shear stress acting on an overlapping joint.

Legging

Stringing that occurs when adhesive-bonded substrates are separated.

Linear Shrinkage

The shrinkage encountered in an adhesive in one direction.

Load

The force applied to a body, joint or bond.

Longitudinal Grain

Grain orientation in which wood fibres are parallel to the length of the tree.

Lumber

Raw material obtained from the dry kiln, still in rough form.

Lumber Yield

The percent of usable, defect-free lumber that can be cut from a rough cutting, board, or bundle of lumber.

LVL

Laminated Veneer Lumber

M

MDF

Medium Density Fibreboard.

Mechanical Adhesion

Adhesion between surfaces in which the adhesive holds the parts together by interlocking action.

Mega

Prefix meaning one million (M).

Melt-Back

Occurs when glue has been over-softened and is forced back along the barrel of the applicator by trigger pressure. If your glue gun is left on for more than 30 minutes without being used either turn the tool off or dispense a small amount of adhesive, this will help prevent melt-back. Melt-back can cause serious burns!

Membrane Press

A hot press design which permits foils, laminates or veneer to be bonded to an uneven surface, by using a flexible rubber membrane that is inflated with a hot fluid.

Meter Mix and Dispense Machine

A machine designed to bring accurately measured amounts of material together from separate sources for mixing and dispensing.

Methacrylate

A modified acrylic adhesive.

MFFT

Minimum Film Forming Temperature. The minimum temperature that an emulsion based adhesive can successfully form into a homogeneous film when drying. At lower temperatures, a chalky white brittle film is formed with poor adhesion.

Micro

Prefix meaning one-millionth part.

Migration

Movement of substances from the interior to the surface of a plastic.

Milli

Prefix meaning one thousandth part (m).

Modifier

A chemically inert ingredient added to an adhesive that changes its properties.

Moisture Content

Percent moisture content is equal to the weight of water divided by the weight of bone-dry wood x 100.

Moisture Meter

An electronic device used to determine the moisture content of wood stock.

Molecular Weight

The sum of the atomic weight of all atoms in a molecule.

Monomer

A simple compound whose molecules can join together to form polymers

Motionless Mixer (also see Static Mixer)

A mixing device with no moving parts, used to combine two or more substances. Commonly found attached to cartridge systems or meter mix equipment.

MSDS

Material Safety Data Sheet.

Mucilage

An adhesive made from a gum and water. Also in a more general sense, a liquid adhesive which has a low bond strength.

N

Nano

Prefix meaning one-billionth.

Newtonian Fluid

A fluid whose viscosity is not affected by changes in shear rate. See thixotropic and dilatant.

Nip Roller

A roller system for applying high pressure for an instant, over a small area. This system is frequently used for hot melt, fast-set adhesives, or contact cements.

Non-flammable

Incapable of being easily ignited or burned.

Non-porous substrate

A substrate that does not allow materials to pass through, usually related to liquids but includes gases and some solids.

Nylon

A generic name for a specific family of thermoplastic polyamides invented by DuPont.

O

Open time

The time that the glue may be left open to the air after application. Same as working time. Same as open assembly time.

Oxygen bomb test

An aging test for adhesives. Five hundred hours exposure to the conditions in this test indicate whether a product will provide useful service over a much longer time period.

P

Polyamide (PA)

A higher performance polymer that is used to formulate adhesives with better resistance to temperature extremes. Typically -60C to 130C. These adhesives are more chemical resistant but tend to be slightly less sticky than adhesives based on EVA.

Polypropylene (PP)

Used to formulate adhesives with specific adhesion properties and delayed setting time. Often used for spray formulations. Service temperatures -30C to 110C depending upon formulation.

Polyvinyl Acetate

Polyvinyl acetate is a component of a widely-used type of glue, referred to variously as wood glue, white glue, carpenter’s glue, school glue or PVA glue

Post cure, verb

Exposure of an adhesive assembly to additional curing, following the initial curing process, for the purpose of modifying specific properties.

Pot life

The period of time during which an adhesive, after mixing with catalyst, solvent, or other compounding ingredients, remains suitable for use.

Pot Life (also see Work Life)

The length of time an adhesive remains usable for mixing.

Potting

Enclosing an article in an envelope of adhesive. See encapsulate.

PPE

Personal Protective Equipment.

PPM

Parts per million.

Press time

The period required for a joint to be held under pressure.

Primer

A coating applied to a surface, before the application of an adhesive, to improve the adhesive performance.

Psi

Pounds per square inch.

PVA

See Polyvinyl Acetate

PVC (Polyvinyl Chloride)

A polymer of vinyl chloride.

Pyrometer

A device for measuring surface temperature.

R

Radio Frequency Gluing System

Radio Frequency Gluing is a process in which high frequency radio waves are used to heat substrates, causing the adhesive between them to dry.

Reactivity

Tendency of a substance to undergo a chemical reaction with itself or another material with the release of energy.

Release paper

A coated sheet (usually silicone based), used to package an adhesive film or mass, which can be easily removed prior to use.

Resin

A class of organic products of both natural and synthetic origin, usually possessing high molecular weights with no definite melting point. Resins are generally insoluble in water and have little or no tendency to crystallize. However, certain resins, such as some polyvinyl alcohols are dispersible in water. Others, such as polyamides are readily crystallised.

Resistance

The opposition to current flow through a material measured in Ohms.

Resistivity

The ability of a material to resist passage of electrical current either through its bulk or surface.

Rheology

The study of the flow of matter.

Ring & Ball Softening Point

A method of measuring the temperature at which the adhesive softens, quoted in degrees. Not to be confused with Heat Resistance

Rosin

A resin obtained as a residue in the distillation of crude turpentine from the sap of the pine tree (gum rosin) or from an extract of the stumps and other parts of the tree (wood rosin).

RTV (Room Temperature Vulcanising)

The tendency of an adhesive to cure at room temperature. Changing from a liquid/paste to a solid, flexible rubber.

S

Sealant

An adhesive that prevents the passage of gases, dust, liquids, etc. into or out of the assembly at that point.

Sensitisation

A state of bodily immune response in which further exposure to a substance (sometimes at very low levels) produces an immune or allergic response.

Set

To convert an adhesive into a fixed or hardened state by chemical or physical action.

Set Time

The time taken to reach a bond strength capable of handling.

Setting Temperature

The optimum temperature to promote the setting of an adhesive.

Shear

The effect of forces acting in opposite but parallel directions.

Shear Strength

The maximum shearing force, per unit area, an adhesive bond will endure before breaking. A shearing force is created when the two substrates bonded together are forced in opposite directions in the same plane as the bond.

Shelf-Life

The usable storage time of a material. Each adhesive will have its shelf life specified by the manufacturer.

Silicone

Used mainly as a sealant, Silicone is known for its high and low temperature resistance (-100°F to +600°F). Silicone is reliable and relatively easy to handle.

Sizing

The application of a material to a surface in order to fill pores and thus reduce the absorption of an adhesive/coating applied afterwards. Also to modify the surface properties of the substrate to improve the adhesion.

Slippage

The movement of substrates with respect to each other during the bonding process.

Softwood

Wood from coniferous trees (i.e. pine, fir and spruce).

Solids content

The percentage by weight of the non-volatile materials in an adhesive formulation.

Solvent

A liquid that can dissolve other substances.

Specific Gravity

The density of a substance divided by the density of water. Since water has a density of 1 gram/cm3, and since all of the units cancel, specific gravity is the same number as density but without any units.

Specific Heat

The quantity of heat needed to raise the temperature of a mass of material as compared with the same amount of water.

Speed of Set

The rate at which an adhesive attains handling strength

Speed of set test

A series of tests run to determine how fast a given glue can build strength under ideal conditions.

Squeeze out

Adhesive pressed out at the bond line due to pressure applied on the substrates.

Stability

The ability of a material to remain unchanged.

Static Mixer

A device that consists of a series of internal elements within a plastic tube. As adhesive components are forced through the mixer, the components are repeatedly divided and then mixed together, thus creating a complete and uniform mixture. See meter mix

Step Joint

A small change in height of adjacent staves in a panel caused by changes in moisture content. Also known as planking.

Storage life

The period of time that an unopened container of adhesive can be stored under specified temperature conditions and remain suitable for use. Same as shelf life.

Strength, dry

The strength of an adhesive joint tested immediately after drying under specified conditions or after a period of conditioning in the standard laboratory atmosphere.

Strength, wet

The strength of an adhesive joint tested immediately after removal from a liquid in which it has been immersed under specified conditions.

Stress

Force per unit area.

Stringiness

The formation of threads when adhesive transferred between surfaces is pulled apart.

Structural Adhesive

A bonding agent used for transferring required loads between substrates exposed to service environments typical for the structure involved.

Substrate(s)

Material(s) to be bonded.

Sunken Joint

A depression at the joint between two pieces of wood caused by machining of the panel before the joint has fully set.

Surface preparation

The physical and /or chemical preparation of a substrate to make it suitable for adhesive joining.

Synthetic

Something produced by chemical means that does not occur naturally.

T

Tack

The property of an adhesive that allows it to form a bond of measurable strength immediately after adhesive and substrate are brought into contact.

Tack, dry

The property of certain adhesives to adhere on contact to themselves even though they appear dry to the touch.

Tackifiers

Are added to an adhesive to increase the wet-tack of the adhesive. It works by forming cross-linking bonds across the Polymer chains.

Tackiness

The stickiness of the surface of an adhesive.

Tannic acid

A compound that is most commonly found in oak, cherry, cypress and redwood trees.

Telegraphing

A condition in a laminate in which irregularities of an inner layer are visibly transmitted to the surface.

Temperature, setting

The temperature to which an adhesive or an assembly is subjected to set the adhesive.

Tensile Strength

The maximum stress a material subjected to stretching can withstand without tearing.

Thermolabel

A self-adhesive thermometer strip that can be placed on a panel before pressing to measure the maximum press or panel temperature.

Thermal Conductivity

Ability of a material to conduct heat.

Thermoplastic

A material capable of being repeatedly softened by heat and hardened by cooling.

Thermosetting

Having the property of undergoing a chemical reaction by the action of heat, catalysts etc., which cannot be reversed.

Thinner

A volatile liquid added to an adhesive to reduce its viscosity.

Thixotropic

A material with a thick consistency at rest but flows under pressure or agitation

U

Urethane

A family of polymers ranging from rubbery to brittle. Usually formed by the reaction of a di-isocyanate with a hydroxyl.

UV

Ultraviolet Light.

V

Vacuum Press

A laminating or veneering press in which the panel is placed inside of a flexible bag connected to a vacuum pump.

Vehicle

The liquid component of a material.

Veneer

A thin (usually less that 1/8″ thick) piece of wood.

Viscosity

The measure of the resistance of a fluid to flow usually expressed in centipoises or milli-Pascals per second (mPas-1). A higher reading indicates a thicker material.

VOC

Volatile Organic Compound.

Voids

Gas or air pockets trapped within a material.

Volatile Organic Compounds (VOC)

Any organic molecules that evaporate easily.

Volatility

Measure of a liquid’s tendency to evaporate at room condition.

Vulcanisation

Rubber is reacted with Sulphur to produce increased tensile strength and resistance to swelling and abrasion, and is elastic over a greater range of temperatures.

W

Warp

A significant variation from the original, true, or plane surface.

Webbing

Filaments or threads that may form when adhesive transfer surfaces are separated.

Wetting

The flow of an adhesive over a surface.

Wicking

The flow of a liquid along a surface into a narrow area.

Wood failure

The rupturing of wood fibres in strength tests on bonded specimens, usually expressed as the percentage of the total area involved which shows such failure.

Working life

The period of time that an adhesive, after mixing with a hardener or catalyst, remains suitable for use.

Working-Time

Same as Gel Time.