Surfers Guide to Epoxy Surfboard Construction

Isle Surfboards manufactures the highest quality epoxy surfboards and epoxy stand up paddle boards. This is a helpfull guide to explain sometimes confusing details between the different surfboard construction methods

The phrase "epoxy" and "fiberglass" surfboard - what does it mean?

Lets get our surfboard terms straight - In order to speak like you know a thing or two about surfboards you need to learn and understand these below terms and what they mean -

EPOXY - This is a hard type of resin used in the construction of epoxy surfboards with an EPS foam core
EPS- Acronym for Expanded Polystyrene, This is a lightweight beaded foam used in the production of all epoxy surfboards
POLY- Acronym for Polyester resin used in the production of the (traditional ) polyurethane foam core surfboard
PU - Acronym for Polyurethane blank used as the core of a board glassed with polyester resin
FIBERGLASS CLOTH - Weight cloth used in the construction of epoxy glassed surfboard and poly glassed surfboards.

All boards use fiberglass cloth for the most part and its main construction is determined by the core and resin you choose. So the industry standards are EPOXY/EPS and POLY/PU. Both of these methods of construction are laid up with FIBERGLASS CLOTH. So when you say the phrase "fiberglass surfboard" it is not correct. You need to specify EPOXY/EPS or POLY/PU. Now you are light years ahead of the general public.

What is an Epoxy surfboard? How is it different from a traditional fiberglass board?

Epoxy resin is used in many applications other than surfboard building such as boats, electronics and aerospace parts. The epoxy resin is stronger and more ding resistant than polyester resin. Epoxy resin can only be used with polystyrene foam , and boards made in this fashion are referred to as epoxy surfboards based on the use of the epoxy resin with this foam. The epoxy boards have been associated with names like Surftech, Boardworks, Firewire etc.

We know it's a bit confusing since there are so many different types of epoxy surfboards in the market. So first we will explain the traditional fiberglass surfboard construction and then go on to explain the different types of epoxy surfboards and brands. But first let's explain the difference….

Traditional Vs. Epoxy

1. Traditional Fiberglass (POLY/PU) Surfboard Technology:
   Poly or polyester represents a traditional fiberglass surfboard. PU or polyurethane foam is the foam of the traditional fiberglass board. When you think of this type of surfboard you think of Clark Foam. A traditional fiberglass board is hand shaped or CNC machine shaped out of a polyurethane foam core. The foam core is laid up with weighted fiberglass cloth and laminated with polyester resin. The board is cured and then sanded to a desired smoothness and viola! you have a traditional “fiberglass” surfboard or PU. These types of surfboards are most notable for their performance and specific flex properties and have been around since the 1960s.
2. Epoxy Surfboard Technology (EPOXY/EPS):
   Before we get into the different types of epoxy surfboards, let's first explain the 2 different types of epoxy foam used in the construction of these boards…

There are 2 types of polystyrene foam cores used with Epoxy Resin

1. Expanded Polystyrene:
   The EPS is beaded foam and the foam is much like that of your beer coolers in the grocery store or inside your bumper on your Mazda Miata. Since the foam maintains a structure based on an open cell it will absorb water like a sponge if exposed to water. Some limitations are the poor strength, low resistance to compression, and difficulty of shaping due to the small round spheres. If you are buying a lower priced epoxy board you can basically count on it to be expanded polystyrene in the core. These epoxy boards hold up well when paired with epoxy resin. Just make sure that if you crack your expanded polystyrene epoxy board, that you repair it before taking it back into the water! Isle ECORE Epoxy surfboards are constructed of EPS foam.
2. Extruded Polystyrene Core:
   This is a closed cell core and since it is “closed” it repels water and is more resistant to compression and damage. One of the most notable differences from the Expanded Styrene Cores is the flex patterns are greatly enhanced due to its closed cell structure which will allow for greater response under pressure. All your higher end epoxy boards utilize this type of construction. Examples of this type of epoxy construction is Isle XPS Epoxy boards.

Hand Shaped Epoxy Vs Molded Epoxy

1. Hand Shaped Epoxy Surfboard:
   Our Isle Ecore Epoxy Surfboards and XPS Epoxy Surfboards are both hand shaped. This type of epoxy surfboard is quite similar to the fiberglass board as explained above. The only difference is the polyester resin is substituted for epoxy resin and the polyurethane core is substituted for a polystyrene core. The styrene is hand shaped or machine shaped and then laminated with epoxy resin and fiberglass cloth. In the aftermath of the Clark foam shutdown, many shapers quickly switched to this method as polystyrene foam cores are readily available in the marketplace in order to meet demand when traditional polyurethane foam was unavailable. They are very common amongst big brand name shapers and are widely available and customizable due to the fact they are all finished by hand.
2. Molded (POP-OUT) Epoxy Surfboard:
   In this type of epoxy rather than hand shape the polystyrene core, a mold is created based on the dimensions of a traditional fiberglass plug. The hollow mold is then injected with the polystyrene foam to mold it into shape based on the master, and then covered with several layers of fiberglass cloth, epoxy resin, and typically a layer of high density foam to reinforce the structure and placed in a vacuum or press to compress all the materials together, hence the term sandwich construction. Typically a heating element can be built into the mold to allow the epoxy resin to cure at a higher temp increasing the strength. The techniques employed during these steps can be varied by different companies to get the desired strength, flex, weight, etc..
3. Hand Shaped Epoxy with High Density PVC Compression Step:
   Surftech Epoxy surfboards represent this type of technology. This is very similar to the 1st type of epoxy surfboard as explained above. The difference is a very strong PVC layer is compressed onto the EPS and glassed with epoxy resin. This compression step adds tremendous extra strength. It is much more difficult to build as the boards are not built in mold hence the phrase pop-out. These boards are all hand shaped and refined to duplicate the master copy it is being modeled after.