Epoxy adhesives are a polymer-based resin that is part of the curable adhesive family, which means they require some outside chemical catalyst to create a hardened bond.  They are also known as a two-component adhesive, meaning that the ultimate cured bond requires the mixture of two components together to create the chemical reaction necessary for the curing to take place.  Usually it is two different resins that are mixed, but often it is a powder and a resin as well. 

This type of adhesive is one of the most versatile and powerful adhesives on the market.  It can be made to have a very high bonding strength and usually has a very quick set and cure time because of the near instantaneous mixing of the two parent compounds. Because of these features, it is common to use epoxies for bonding applications requiring a strong connective attachment.  This need exists especially within the aviation and auto industry, where durability, strength, and lifespan all are a safety and legal imperative.

In addition to their strength, they are also one of the most versatile adhesives available.  Epoxy glues exist for metal, plastics, wood, cloth, glass, and cement.