Adhesives and glues are used to bond substrates like metal, glass, plastic, and wood in a wide range of sealing, joining, and attaching applications. Depending on the surface material and adhesive type, different methods are used to create bonds. These methods include air drying, heat drying, and chemical reaction.
Drying adhesives include solvent-based adhesives like contact cements and construction adhesives. These types of adhesives harden as the solvent evaporates from the compound. Heat-activated adhesives include hot melts and some urethane adhesives. Reactive adhesives include methacrylate adhesives and epoxies. These adhesives are usually two-part systems where the bond forms through a chemical reaction once the two parts are mixed.
Adhesive strength is measured by shear strength and peel strength, also known as T-peel strength. Peel strength measures the strength needed to separate materials where the angle of separation is 180 degrees. Sheer strength measures the strength of the bond against the shearing of a surface.