These commodity epoxy manufacturers mentioned above typically do not sell epoxy resins in a form usable to most end users, so there is another group of companies that purchase epoxy raw materials from the major producers and then compounds (blends, modifies, or otherwise customizes) epoxy systems out of these raw materials. This class of companies is typically known as "formulators". The vast majority of the epoxy systems sold are produced by these smaller formulators and they account for greater than 60% of the dollar value of the overall epoxy market. There are hundreds of ways that these formulators can modify epoxies — by adding mineral fillers (ex. talc, silica, alumina, etc.), by adding flexibilizers, viscosity reducers, colorants, thickeners, accelerators, adhesion promoters, etc. These modifications are made to reduce costs, to improve performance, and to improve processing convenience. As a result a typical formulator sells dozens, hundreds, or even thousands of formulations — each carefully tailored to the requirements of a particular application or market.

The applications for epoxy based materials are extensive and include coatings, adhesives and composite materials like carbon fiber and glass-reinforced plastic (although polyester, vinyl ester, and other thermosetting resins are also used for glass-reinforced plastic). The chemistry of epoxies and the range of commercially available variations allows cure polymers to be produced with a very broad range of properties. In general, epoxies are known for their excellent adhesion, chemical and heat resistance, good to excellent mechanical properties and very good electrical insulating properties, but almost any property can be modified (for example silver-filled epoxies with good electrical conductivity are widely available even though epoxies are typically electrically insulating).