Epoxy coatings are composed in two parts, an epoxy resin and a curing agent or hardner, that are mixed prior to application. Epoxy coatings are formulated based upon the performance requirements for the end product. When properly catalyzed and applied, epoxies produce a hard, chemical and solvent resistant finish. They are typically used on concrete and steel to give resistance to water, alkali and acids. It is the specific selection and combination of the epoxy component and the hardener component that determines the final characteristics and suitability of the epoxy coating for a given environment. Important factors to understand how to choose the right epoxy are based on the substrate type, the environmental factors and surface prep. The curing agent contributes largely in how the epoxy turns out when it’s cured. There are numerous curing agent recipes, but one of the more common is a combination of amides and polyamides (which amounts to a variation of ammonia—the difference being the replacement of a hydrogen atom with a carbon + oxygen pair).
Epoxies are often used due to chemical resistance, low porosity and adhesion and bonding properties. Epoxies are also known for their heat resistance and insulating abilities for electrical components and can also be formulated to work in underwater applications.