4 Types of Resin You Need to Know

Resin is extremely versatile and can be molded into a variety of structures and shapes, especially when used in conjunction with epoxy. There are many pros and cons to using different types of epoxy resin and this blog post will give you an overview of them.

What is Resin

Resin comes in many forms, each with its own individual properties. It is often made up of two core components that are combined to set off a chemical reaction, causing the resin to set. These are the hardener, which is the catalyst, and the base resin.

What are the Different Types?

The most common types (and those which this post will cover) are polyurethane, polyester, UV, and epoxy resin. It is important to note that UV resin is slightly different to the others in that it sets after UV exposure, as the name suggests, and so only needs one component rather than two.

Polyester Resin

This form of resin is structurally strong and water resistant, making it a good option for model-making. It is especially used for the building of swimming pools, ponds, and boats with a buch of fiberglass to reinforce it.


Before using the resin, the two components must be integrated, and a hardener will need to be added beforehand. Mix these thoroughly to ensure neither of the two settles at the bottom. Adding more, or less, hardener will impact the curing time of the resin. After combining the components, you can then use the resin to make a mold. To avoid pockets of air getting trapped and creating bubbles, you must make sure to apply this resin to the glass fiber in one direction.

  • Highly affordable
  • Predictable drying-time (this depends on amount of hardener added)
  • Water-resistant
  • Strong, unpleasant odor
  • Technical and challenging mixing process

As a side note, polyester resin can also be used to laminate. If you choose to do this, you must first apply a layer of resin to the surface, then to a sheet of glass fiber. After this, you need to apply a third layer to ensure the glass fiber mat is flexible and can be shaped without resistance.

Epoxy resin

Highly versatile and more solid and durable, epoxy resin is generally the go-to for resin-based projects, like jewelry, river table, tumblers and etc. It’s inexpensive, easy to use, and very long-lasting, making it ideal for all skill levels.


How you use epoxy resin depends on what project you are undertaking. The resin should be applied a layer at a time, with each being allowed to dry before the next coat. Once dry, the resin can be sanded down—however, be aware that you should not attempt this between applying any further coats.

You can also use coating or casting epoxy resin to increase durability further. Briefly, here is a little more information on each.

Coating Resin: To increase an item’s strength and longevity, you can coat the item with a protective, glossy finish. It is especially recommended to treat concrete flooring with coating resin.

Casting Resin: With a thin consistency and low viscosity, casting resin is ideal for filling hollows in wood or other similar materials. You can either apply it in a coat, or fully submerge your item to better preserve it. Although very useful, casting resin does have a long drying time, which is a slight negative.

  • Easily customizable
  • Long-lasting
  • Highly durable
  • Inexpensive
  • Highly versatile (epoxy resin has a variety of uses)
  • Unsuitable for humid environments as it requires a dry atmosphere to properly set
  • Tends to yellow after direct exposure to sunlight

P.S. Epoxy resin also falls into 4 types, learn more here.

Polyurethane Resin

This resin is much more versatile. It is highly durable and is often used for casting molds as it becomes solid after heat is applied to it. Polyurethane resin is often used across multiple industries due to the variety of items it can be used to make. Primarily, this form of resin is found in the automotive industry, however there are a wide range of other appliances that contain polyurethane.


Depending on what you are using this resin for, the application process will differ. If you are making a cast, for example, two components will need to be combined prior to filling the mold with resin. Polyurethane resin can additionally be used to make surfaces less slick.

  • Heat resistant once set
  • Able to be used as an electrical encapsulate
  • Fast-setting
  • Easily mixable due to its great flow
  • True to size (there is very little shrinkage during setting)
  • Smells unpleasant when curing
  • Cannot be welded once set
  • Can foam due to moisture sensitivity
  • Is not adhesive (in comparison to epoxy)
  • Requires the use of an additional additive due to UV light sensitivity

UV Resin

Needing only one component, UV resin is a little different to the others. Furthermore, it only needs UV light to trigger the chemical reaction that causes setting, which it does quickly.


uv resin

UV resin is relatively easy to use as it only begins to set after exposure to UV light. The first step to using this resin is to add color to it, should you wish to. Then, you can coat the item of your choice with it. It’s best to keep in mind that both the thickness of the resin and the dimensions of the item you have coated will affect the drying time.

  • Incredibly fast drying time
  • Only begins to set after UV light exposure (giving you plenty of time to work with it)
  • Very easy to use as no mixing is required
  • Very limited shelf life (around six months)
  • Specifically requires a UV lamp, which can be costly
  • Compared to other resin, UV is particularly expensive
  • Cannot be used to cover large regions as it must be applied in thin layers


The type of resin you use should depend entirely on your chosen project. Once you have your project and its requirements in mind, then you can move on to tackling which resin to use. As this article explains, there are many benefits and downsides to each form of resin. However, resin’s greatest powers are its ability to camouflage over the item it is applied to, its durability, malleability, and ease of use.

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