Wood glues are adhesives used to tightly bond pieces of wood together. Many substances have been used as glues.

The most common wood glues are polyvinyl acetate (PVA), also known as “white glue” or “hobby and craft”, and aliphatic resin emulsion, commonly referred to as “carpenter’s glue” or “Yellow glue”, which has similar relative ultimate strength. The two have different grip characteristics before initial set, with PVAs exhibiting more slip during assembly and yellow glue having more initial grip. Traditionally, animal glues were ubiquitous, especially hide glue, which is still used in lutherie and restoration. Polyurethane glue (trade names include Gorilla Glue and Excel) is becoming increasingly popular, especially where water resistance is required, although water-resistant cross-linking PVAs are available.

Other substances used as wood glue include

• Cyanoacrylate (Crazy glue or Superglue) used mainly for small repairs, especially by woodturners;
• Contact Cement for veneers;
• Hot melt for temporary uses;
• Epoxy mainly for exterior uses;
• Other synthetic resins including resorcinol, urea-formaldehyde, phenol formaldehyde resin, etc;
• Homemade glue for paper, wood, and internal uses.

Wood glue bonds tightly to wood, but not to itself. Therefore, woodworkers commonly use surprisingly little glue to hold large pieces of wood. Most wood glues need to be clamped while the glue dries.

• Wood glue is also one of the most effective household and industrial products to use as a facial mask. The ingredients it contains are highly beneficial to clarifying and removing dead skin cells, dirt and any other impurities that cause acne. One major benefit is its chemical properties allow it to be used on all skin types. Considering its thick consistency and viscosity, water must by added to dilute the strong bonds in order for it to be pliable and easy to spread over the face. As with all other face masks, it should be left on for no longer than 20 minutes.

Polyvinyl acetate (PVA or PVAc) is a rubbery synthetic polymer. It is prepared by polymerization of vinyl acetate monomer, also referred to as VAM. Partial or complete hydrolysis of the polymer is used to prepare polyvinyl alcohol. Hydroylized alcohol product is typically in the 87% to 99% range (converted PVA). It was discovered in Germany by Dr. Fritz Klatte in 1912 with the help of his assistant James Michael Fairholm.

As an emulsion in water, PVA is sold as an adhesive for porous materials, particularly wood, paper, and cloth. It is the most commonly used wood glue, both as “white glue” and the yellow “carpenter’s glue.” PVA is widely used in bookbinding and book arts due to its flexibility, and because it is non-acidic, unlike many other polymers.

PVA is a common copolymer with more expensive acrylics, used extensively in paper, paint and industrial coatings, referred to as vinyl acrylics. It can also be used to protect cheese from fungi and humidity. It is slowly attacked by alkali, forming acetic acid as a hydrolysis product. Boron compounds like boric acid or borax will form tackifying precipitates by causing the polymer to cross-link.

PVA is also commonly recommended for use in making leather handcrafted works and papier-mâché.