Phenolics are available as liquids that cure by evaporation of the solvents. For greatest bonding strength, the solvents are allowed to evaporate before the parts are joined under heat and pressure. Phenolic adhesives are also available in thin sheets that are applied to the surfaces to be bonded; sheet bonding may be done under heat and pressure, as for joining plywood.
The commonly used phenol-formaldehyde adhesive provides good adhesion to wood and other porous materials. Other phenolic blends as phenolic-epoxy, phenolic-polyamide, etc., are used to bond metals or glass.