Wood glue

Wood glue is an adhesive used to tightly bond pieces of wood together. Many substances have been used as glues.

Several wood glues have poor "gap-filling" ability, meaning they either soak into the wood and leave the gap empty, or remain to fill the gap but have little structural integrity. Therefore, woodworkers commonly use tight-fitting joints that need surprisingly little glue to hold large pieces of wood. Most wood glues need to be clamped while the glue sets. Epoxy resins and some other glues can be thickened with structural fillers (or with thicker formulations of the resin) to help fill gaps, however it is preferable to try to minimize gaps in the first place.

Fine Woodworking magazine ran a number of tests to evaluate the mechanical resistance of wood joints with different glues:

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