Titebond Wood Glues: Product and Application Technical Guide II
Common Gluing Terms
ANSI / HPVA
American National Standard Institute / Hardwood Plywood & Veneer Association
Bond Strength
The unit load applied in tension, compression, flexure, peel, impact, cleavage or
shear, that is required to break an adhesive assembly with failure occurring in or
near the plane of the bond. Typically reported in pounds per square inch (psi).
Clamp Time
The period of time that the substrates being glued together need to remain clamped.
Closed Assembly Time
The period of time between putting the glued substrates together and clamping.
This time allows for moving the pieces into their final position.
Chalk Temperature
When glue dries, the loss of water pulls the adhesive particles together with
enough force to form a continuous film. If the drying temperature is below a
critical point, water evaporation is not sufficient to pull the particles together,
leaving them in the joint. The dried film in the joint will appear whiter than
normal. This is known as “chalking” and the critical temperature is the “chalk
temperature.” When chalking occurs, the glued joint loses strength and could
result in a failed bond.
Crackling
A faux finish that creates a weathered or “antique” appearance on wood substrates.
Freeze-thaw Stability
The ability of a product to remain usable after it has been frozen and thawed.
Some wood glue will have a “cottage cheese” look after freezing. If this happens,
shake/stir glue to original form.
Open Assembly Time
Period of time between initial glue application and putting the substrates together.
Polyvinyl Acetate (PVA) Glue
Any glue consisting primarily of polyvinyl acetate polymer. This category
includes most traditional white glues and more advanced yellow aliphatic resin
glues. Although PVA glues can vary in strength, flexibility, water-resistance and
sandability, they offer good performance, cleanup with water and are non-toxic.
Because PVA glues tend to “creep”, or slowly stretch under long-term loads,
they are not recommended for structural applications.
Porous Substrate
A substrate that is permeable by air, water, etc.
Speed of Set
The rate at which an adhesive can build strength.
Squeeze-out
Adhesive pressed out at the bond line due to pressure applied on the substrates.
Starved Joint
A joint in which there is not enough glue for a proper bond to form.
Stepped Joint
A joint in which there is a small change in height of adjacent pieces of wood
caused by changes in moisture content.
Storage Life
The period of time during which a packaged adhesive can be stored under
specified temperature conditions and remain suitable for use.
Sunken Joint
A joint where the wood at the joint is lower or has “sunken” when compared to
the surrounding wood; caused by machining the piece before water from the
glue has completely evaporated.
Tack
The property of an adhesive that enables it to form a bond of measurable
strength immediately after the adhesive and substrate are brought into contact
under low pressure.
Total Assembly Time
The period of time between the initial glue application and clamping.
Volatile Organic Compound (VOC)
A compound of carbon which participates in atmospheric photochemical
reactions. The VOC is a measured or calculated number that reflects the amount
of volatile organic material that is released from a product as it dries.
