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TwitterEpoxy Surfboard Construction Guide
Introduced only a couple of decades ago, epoxy resin is a relatively new trend in the surfboard industry. Traditionally, surfboards have been treated with polyester resin; however, many shapers are now turning to epoxy for its incredible strength and durability. This article talks about the differences between polyester and epoxy resins, the types of boards made using epoxy, the foam options for epoxy construction, as well as its benefits and problems.
Traditional vs. Epoxy Construction
The typical modern surfboard is made using polyurethane foam and polyester resin. While this combination proved successful as the standard for many years, the industry couldn’t turn its back to the benefits of epoxy resin and has begun to embrace the idea.
To begin with, epoxy resin is a healthier alternative to polyester. When working with polyester resin, glassers must wear masks to ensure that the harmful chemicals won’t damage their respiratory system. For years, manufacturers have struggled to come up with a method of making surfboards that would be less destructive, both to their health and the environment. It seems that epoxy might fit the bill. Epoxy emits 50-75% fewer VOCs (volatile organic compounds) than polyester resin, which means a decrease in harmful chemicals in the shop and the environment in general. In fact, epoxy is a common household item, safe to use without a mask and with only moderate ventilation.
One possible difference between the two types of resin applications is their ability to withstand the test of time. Since the epoxy technology has only been part of the mainstream market for a few years, it’s hard to gauge how it compares to polyester. Some experts, such as those from the Surfrider foundation, say that the added durability from the epoxy translates to a longer-lasting board, while proponents of polyester claim that the epoxy yellows and fails over time, especially when left too long in the sun. While further research and development is necessary to know for sure, epoxy boards seem to last at least as long as their polyester counterparts when cared for properly.
On a final comparative note, epoxy is lighter than polyester. Under most circumstances, resin makes up a large part of a completed board’s overall weight. Not only is epoxy lighter than polyester, but less is needed per coat. This ends up meaning a lighter surfboard – a big plus for most surfers.
Epoxy-Compatible Foams
As discussed above, most surfboards are made with polyurethane foam as their core. Polyurethane (PU) foam has many benefits that have made it a front-running choice for so long: it is very easy to handle and shape, it is inexpensive, and it can be found in several shapes and sizes. Unfortunately, making PU foam requires the use of highly toxic materials, not to mention that it is also highly susceptible to water damage during storage.
While PU is the most common type of foam used in surfboard construction (it was the only type sold by former blank giant Clark Foam for over 40 years), epoxy resin isn’t compatible with it. Instead, shapers use polystyrene foam, an alternative foam that is lighter weight and not as chemically harmful to those who handle it. Polystyrene foam comes in two varieties – expanded and extruded – each compatible with epoxy resin, and each with its own positives and drawbacks.
EXPANDED (beaded foam, Styrofoam)
Expanded, or beaded, foam (EPS) is a relatively inexpensive and incredibly lightweight surfboard core. Manufacturers produce sheets of EPS by feeding tiny polystyrene spheres into a machine, then introducing steam coupled with a trace amount of pentane gas to expand the beads and mold them to one another. The end result is an open cell foam, meaning that is very water absorbent. To combat this issue, shapers who use EPS foam must add extra layers of fiberglass and epoxy resin to prevent any dings from penetrating deep enough to reach the foam.
Pop-out boards are made using EPS foam, because the beads can be formed into specific molds. The soft outer portion of a pop-out is an ideal match for the EPS foam, keeping dings to a minimum and preventing leaks from entering the foam core. However, very few hand shapers use EPS foam, because it is difficult to work with and nearly impossible to fine-tune with shaping tools (the beads retain their spherical shapes so well that any sanding causes whole chunks of foam to fall off, leaving the edges jagged).
EPS foam is cheap, light and can be molded into various shapes and sizes. However, in addition to being highly moisture absorbing, beaded foam has a few other noteworthy drawbacks: EPS foam blanks have poor flex patterns and they are more susceptible to dents caused by compression. Again, the extra layers of fiberglass and resin work to prevent these problems from affecting the finished board.
EXTRUDED (closed cell)
Extruded foam (XTR) is made using expensive machinery and computers. The machines melt polystyrene crystals down, using additives and a blowing agent to essentially deflate and combine all of the ingredients together. The result is a fluid that expands as it cools, forming solid blocks of XTR foam. The foam is closed cell, so it blocks out moisture – a big plus in the watery world of surfing.
The process of making XTR foam is time-consuming and costly. The price of the foam itself, coupled with the fact that most XTR epoxy boards are hand-shaped, does unfortunately lead to a more expensive finished board – but one with several benefits for discerning surfers. Not only is the foam core moisture-wicking and stronger than other types of foam, it is also extremely resistant to dings and compression-caused dents. XTR foam also has a good flex pattern, so it’s responsive on the water.
The problem with closed cell foam is two-fold. First, as mentioned above, it is expensive. You will almost always pay more for an XTR board than one made from EPS. Second, there have been reports of bubbles and delamination in the decks of some closed cell boards, caused by gas build-up between the foam, fiberglass and resin layers. However, some companies (such as Channel Islands) have made huge developments in XTR-constructed boards, finding ways to allow the gases to escape without compromising the integrity of the surfboard.
Types of Epoxy Boards
Like regular surfboards, epoxy boards are manufactured using several methods and materials. Here we take a look at the most common types of epoxy boards:
HAND-SHAPED/COMPUTER-ASSISTED
Hand-shaped epoxy boards are made using roughly the same construction method as regular polyester boards. The difference lies in the type of foam used (see “Epoxy-Compatible Foams” above) and in the glassing process. Rather than using polyester resin mixed with a hardening agent, the glasser applies coats of epoxy to bind the fiberglass to the foam. The entire process is faster when epoxy is used, because the waiting period between coats is shorter.
Some shapers will start with a rough block of foam, cutting and shaping it by hand from start to finish. Others will feed their design into a computer-assisted machine, which cuts the foam to size. However, they still fine-tune the shape by hand. Any hand-shaped or hand-tuned board, especially when it’s customized, will be relatively expensive. The shaper spends a lot of time working with each board, so the end result is usually worth the added cost.
Anacapa and Channel Islands are just a couple of the surfboard manufacturers that produce hand-shaped or hand-tuned boards.
MOLDED/POP-OUT/SANDWICH
Rather than shape the blank by hand, some companies with high volume sales will make a mold of a surfboard design for repeated use. These molds are injected with polystyrene foam, which forms to the desired shape and can then be glassed. Once the fiberglass cloth, epoxy resin and an added layer of high-density foam are added, the entire thing can be placed into a vacuum or press to compress it into its final shape. Because molds and compression are used, these surfboards are termed pop-out or sandwich style. They tend to be the cheapest type of surfboard, used primarily by beginners. The top manufacturers of pop-out surfboards are Bic, NSP (New Surf Project) and South Point.
There are also boards that are shaped by hand, but are first subjected to a compression machine, which sandwiches a layer of PVC into the polystyrene foam. These are more expensive and of a higher quality than the pop-out sandwich boards, because a shaper designs the boards individually rather than using a mold. SurfTech, for example, uses this process for their surfboards.
Cutting-Edge Technologies
TL2
SurfTech has taken their Techlite core (fused cell foam, virtually waterproof) technology to a new level with their TL2 surfboard design. The Techlite core is further improved upon with the addition of an Acrylite skin, which is glassed onto the board using epoxy resin. The Acrylite skin and the epoxy coating work with the core material to create an incredibly strong, responsive surfboard. The extra strength means that no stringer is needed, so the board is more flexible and springy in the water as well. Like all epoxy boards, the TL2 is made using chemicals that are much less harmful to the environment, which is always a good thing. They are incredibly lightweight and drive hard, giving experienced surfers the performance characteristics they require to go big.
S CORESalomon recently debuted the S Core blank technology, which combines airplane wing structures in the core with ultra-lightweight materials to create a seriously sturdy board. The carbon composite, extruded polystyrene blanks are stronger and more flexible than traditional PU versions. They are not made using sandwich construction; rather, each board is formed using computer-assisted machines, then hand-tuned to shaper specifications. The result is a quick, responsive board that is easy to pick out in a crowd – they are all bright blue!
Epoxy: Pros and Cons
Here is a summarizing list of the pros and cons of using epoxy resin on surfboards, as opposed to traditional polyester resin:
| PROS | CONS |
| Stronger More expensive (can be) | Lighter Less customizable flex patterns |
| Safer to breathe Slower in the water (can be) | Environmentally friendly |
| Clear finish | Less resin required per board |
Now that you understand the basics on surfboard manufacturing, you’re ready to learn about wetsuits.
