Epoxy adhesives

Epoxies are adhesive systems made by a complex chemical reaction. Various resins are made synthetically by reacting two or more chemicals. The resultant resin can then be reacted or cured by the addition of another chemical called a hardener, or catalyst. The basic epoxy resin systems are further modified to change their physical properties by the addition of such things as flexibilizers for impact resistance and flexibility, diluents or solvents to reduce the viscosity fillers and reinforcements like glass fibre, alumina, silica sand, clay, metal powders and flakes to change properties such as heat and electrical resistance, fire retardance, strength and adhesion to certain substrates or materials.

Sources/Properties:
Epoxy adhesives are available in one part, two part and film form and produce extremely strong durable bonds with most materials.
They allow great versatility in formulation since there are many resins and many different hardeners.
Epoxy adhesives can be used to join most materials.
These materials have good strength, do not produce volatiles during curing, and have low shrinkage. However, epoxies can have low peel strength and flexibility and can be brittle.

Common Uses:
Epoxy adhesives can bond a wide variety of substrates with high strength particularly metals.
They have been used to replace some traditional metalworking methods of joining like nuts and bolts, rivets, welding, crimping, brazing and soldering.
High strength epoxies are used to construct rotor blades of helicopters, attach aluminum skins to the struts of aircraft wings and tail sections.
Skis are laminates of plastics, wood, and metal joined with an epoxy.
The heads of golfclubs are bonded with an epoxy.