Test your gluing knowledge

Answer these true-or-false questions to see what you know about adhesives and gluing. 1997

Presented By: Custom-Pak Adhesives Inc.

True or False:

All glues are the same; they all work on wood. - TRUE or FALSE
There is not one great glue that will do it all. -TRUE or FALSE
All white/yellow glues are the same. - TRUE or FALSE
Yellow glue is strong-White glue is only used by schoolchildren. - TRUE or FALSE
There is no glue like the old hide glue. - TRUE or FALSE
Aliphatic glue is superior. - TRUE or FALSE
Formaldehyde glues are waterbased. - TRUE or FALSE
Water based glues are harmful because they will swell and twist wood. - TRUE or FALSE
Thick glue is better and fills gaps and voids. - TRUE or FALSE
More glue is better. - TRUE or FALSE
More pressure is better. - TRUE or FALSE
More catalyst is better. - TRUE or FALSE
No glues will take a stain. - TRUE or FALSE
Mechanical help such as biscuits or dowels is needed for best edge gluing strength. - TRUE or FALSE
Miters and other end grain can be glued with any thick glue. - TRUE or FALSE
Moisture content is important; gluing air dried lumber is not a good idea. - TRUE or FALSE
Pieces should be assembled as soon as possible after spreading the glue. - TRUE or FALSE
There are glues that will set in 3-5 minutes allowing very fast edge gluing of hardwoods. - TRUE or FALSE
It's OK to machine immediately from press/clamps. - TRUE or FALSE
Heating the glue line will not speed the cure. - TRUE or FALSE
"Water Resistant" on the label means the glue isn't affected by water. - TRUE or FALSE
Glues with toxic chemicals in them shouldn't be used. - TRUE or FALSE
Water based glues can be used as long as the temperature in the shop is above freezing. - TRUE or FALSE
Shops don't need to be humidified in the winter. - TRUE or FALSE
It's OK to glue bowed, bellied or twisted stock as long as it's pulled tight with clamps. - TRUE or FALSE
Glue performance can be easily tested in the shop. - TRUE or FALSE
Powdered glues that require water for mixing are more likely to bleed through veneers than PVAs. - TRUE or FALSE
Glues last forever; there is no shelf life. - TRUE or FALSE

Custom-Pak Adhesives Inc. - Supplying industrial adhesives and resins to the woodworking industry.

Answers:

False There are hundreds of different adhesives formulated for thousands of different applications. Choosing the correct glue for your project could determine its eventual success or failure.

True Although many glues have multiple applications there isn't one that can "do it all."

False White and Yellow glues (Poly-Vinyl Acetates) are formulated with different viscosities, solids contents and chemical modifications, for different applications.

False Color has nothing to do with a glue's strength or quality.

False There are few, if any, applications in which synthetic glues, such as PVA, can't outperform, hide glues.

False "Aliphatic" simply describes a broad family of organic chemicals that includes PVAs.

True Formaldehyde glues, although they have different chemical components, are water based just like PVAs.

False Most commonly used wood glues are water based and will not harm wood if high solids glues are used, assembly times allowed, and spreads are controlled.

False Many applications require a glue that is not thick. Although there are adhesives available that have gap filling qualities, just because a glue is thick doesn't mean it is capable of filling gaps and voids.

False Actually, too much glue can result in a thick glue line and, hence, a weaker bond.

False Too much pressure could result in a starved glue joint and a weaker bond.

False Catalyst levels depend on the glue and specific catalyst formulations. Some catalysts speed cure as they are increased; others slow down the cure rate.

True Although some glues appear to take stains better than others, there is no glue that is stainable.

False Using mechanical fastening devices when edge gluing tends to weaken the glue joint by disrupting a smooth true edge joint that will provide maximum strength. Devices such as biscuits or dowels should only be used to maintain alignment or to add strength in miters and butt joints.

False Gluing end grain may require sizing before gluing and the use of a high solids glue.

True Ideal moisture content for gluing is 6.8%, therefore, higher air dry moisture should be avoided. Higher moisture levels also result in wood movement after gluing with accompanying checks and splits. Lower moisture content may interfere with the glue's ability to properly wet the surface.

False Often, it is better to allow the glue to set for a little while before applying pressure.

False Although there are glues available that will set quickly, strength is often sacrificed.

False Regardless of the glue used, it is a good idea to allow it to cure for 24 hours before machining.

True When using conventional PVA the cure rate is not affected by heating the glue line, in fact, bond development may be slowed.

False Only glues that are "Waterproof" such as Resorcinol Resin will provide absolute protection from moisture.

False Most glues are made with some chemicals that may be considered toxic. With normal precautions, most glues are completely safe to work with.

False Although many glues are "freeze/thaw stable" many do not perform well at low temperatures.

False Many shops become excessively dry during the winter causing numerous gluing problems because of resulting moisture loss from the stock.

False Often, gluing bowed or twisted stock results in undue stress on the glue joint and glue lines that are either too thick or starved of adhesive.

False Because of the myriad factors involved in gluing and testing, the only way to accurately measure glue performance is through a laboratory testing facility.

False Once reconstituted, powdered glues actually have a higher solids content than many PVAs, and therefore are less likely to bleed through veneers.

False All glues have a definite shelf life after which their performance deteriorates significantly.

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