Focus on epoxy resin and polyester resin: what characteristics and how to choose?

Used as floor coverings, in the manufacture of furniture or in the production of all kinds of objects, resins are very versatile and have properties that make them interesting products to work with. You want to use resin for your project but you hesitate between epoxy resin and polyester resin? Here is an overview of these two types of resins that should help you make your choice.

Epoxy resin and polyester resin: the common points 

As you can see, epoxy and polyester resins both belong to the same family of thermosetting resins. This common belonging gives them some common points, of which here are the main illustrations.

- Both epoxy and polyester resins can be laminated. This process, commonly used in shipbuilding or ship repair, involves adding several layers of fibers to the resin to increase its strength. These layers are also called "strata", hence the name.

- Both epoxy and polyester resin can be pigment, powder or sand filled depending on the nature of the project.

- Like epoxy resin, polyester resin should also be processed at a temperature between 15 and 25 degrees.

- Both types of resins can be used on different substrates such as wood, metal, plastic or composite materials.

Epoxy resin and polyester resin: the differences

You now know the main similarities between these two resins. However, you will discover that although similar in some respects, these two products have unique characteristics.

Polyester resin

Polyester resin is the less expensive of the two resins and also the more commonly used. There are two types of polyester resins:

- Orthophthalic polyester resin.

This first category of resin is the best known and least expensive. Very versatile, it is nevertheless very sensitive to humidity which can compromise its resistance over time. 

- Isophthalic polyester resin.

Although it is not waterproof, this type of resin is less sensitive to humidity and therefore allows a more diversified use as well as a more important durability.

It should be noted, however, that polyester resin is more brittle than its counterpart, which is why lamination is often necessary in order to increase its resistance.

Epoxy resin

If the epoxy resin is thermosetting like the polyester resin, it is composed of a kit including the base and the hardener. A mixture must therefore be made by respecting the volumes indicated on the product label.

More versatile and efficient than polyester resin, epoxy allows both bonding and solid assembly. With its increased resistance and adhesion, epoxy adapts to all types of supports and is suitable for all kinds of projects, including those subject to significant mechanical or chemical stress. Contrary to polyester resin, this resin is also waterproof, which further expands its field of possibilities in terms of work.

Good to know: Whether you are handling epoxy resin or polyester resin, it is essential that you wear proper equipment for your safety and health. This equipment must include body, respiratory and eye protection.

Do you have an upcoming project? Would you like more information on these two types of resins? We will answer all your questions.