What are epoxies and how do they work?

An epoxy is a material, typically an adhesive or a plastic, that is composed of man-made polymers that contain epoxide groups. Epoxies are created by thermosetting, which means that their curing is dependent on the temperature of their surroundings.

Curing is a process that involves using a large amount of energy to cross-link polymer chains and create a hard substance.

Mechanism of action

In order to create an epoxy, an epoxy resin is reacted either with a hardener or with the resins themselves. Epoxy resins are designed to be stable when they are at room temperature and only cure in the presence of a curing agent.

Uses for epoxies

A key feature of epoxies is that once curing occurs, it cannot be undone. This makes them an excellent option for creating permanent adhesions. Epoxies can be used to adhere challenging materials. For example, epoxies such as those available at http://www.ct1ltd.com/product-applications/metal-to-metal-adhesive/ can be used as a metal bonding adhesive.

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Types of epoxies

Bisphenol A

These can be available in a wide range of molecular weights, which gives them a large number of applications. Bisphenol A can be cured by several curing agents and is frequently used for flooring systems and solid coatings.

Bisphenol F

These epoxies are not as viscous as those made from Bisphenol A and are considerably more expensive. Bisphenol F resins are more resistant to chemicals than Bisphenol A resins and have lower viscosity.


These epoxies are formed in a similar way to Bisphenol F epoxies due to the fact that Bisphenol F is a type of Novolac resin. Novolac requires a higher curing temperature than those mentioned above, and the epoxy is more delicate. These epoxies are more cross-linked than either Bisphenol A or Bisphenol F. Novolac epoxies have a higher level of viscosity than Bisphenol A or Bisphenol F, which results in higher functionality and greater overall crosslink.

100 percent solid putty epoxies

These are created by adding additional ingredients to liquid epoxies, which bulks them to a putty consistency. They are typically applied at a thickness of 3mm to 12mm. These epoxies can be very useful because they have high water resistance, which means they can be mixed and used underwater. However, the additional fillers required to create them can make them prone to reactions with other chemicals.