PU or Epoxy: Which one is best?
When ordering your next board, you are going to have to make a decision between going with standard PU/PE (polyurethane blank, polyester resin) or EPS/Epoxy (Expanded Polystyrene, otherwise known as styrofoam).
Since Clark Foam (leading PU blank manufacturer in it’s time) closed it’s doors in 2005, EPS had a jump forward as an option while board builders had to wait and test through the issues of new PU foam formulas from new blank manufacturers.
EPS had been used by some since around the 70’s or earlier, but it took this major blank disaster to get the majority of board builders start using the alternative.
Working on the deck of a PU Chemistry Surfboards model.
This day in age, however, EPS foam blanks have become a regular option for most of the surfboard industries brands. The performance attributes, though slightly different than PU, are just as notable.
Now, even the top level elite surfers will sometimes prefer to use EPS/Epoxy boards over PU/PE for certain waves or conditions.
They are both great options, but for us regular surfers who can’t afford an endless quiver, we need to think about these differences and make an informed decision before ordering our next board.
To start, let’s take a look at the standard construction of a Polyurethane blank with fiberglass and polyester resin or PU/PE.
This has long been the standard for most brands, and is the most widely and affordable options still out there. It was into the late 50’s that Hobie Alter began playing around with different PU formulas to make a blank that would be easier to shape and produce than using Balsa wood.
This became a turning point in surfboard manufacturing as the foam was much easier to shape and more constant to work with. The weight of boards dropped and the performance levels went through the roof.
Soon after that, Hobie had a full blown factory pumping out PU blanks and had appointed Gordon Clark to help with the endeavors. Eventually, Gordon would take over the blank manufacturing so Hobie could focus on building surfboards, and as a result, Hobie Surfboards had become the first full on mass surfboard manufacturer paving the path for the surf industry as we see it today.
Asher Pacey easing into his bottom turn on his DHD Twin Fin in PU construction.
Now, PU/PE boards are a little more affordable than their EPS/Epoxy counterparts. They sit a little lower in the water, helping to keep your rail under, giving you a nice “knify” feel when slicing through the waves face.
They are a touch heavier than Epoxy boards so they do tend to handle choppy conditions better and are less prone to being bounced around. Also, as a result of them sitting lower in the water, they make great barrel machines in hollow waves as the rail will sit more in the water instead of on top of it.
They still have the best flex characteristics which we are constantly trying to mimic in EPS/Epoxy boards through different applications of reinforcements, etc, that we will touch on at a later time.
Close up of the Super Brand Superflex construction.
You can’t go counting EPS out as an option though.
EPS is a standard option for many brands these days and for a number of good reasons. One of the most notable difference between EPS and PU is the weight.
EPS foam is much lighter than PU which makes for a great option for the surfers that love to take it to the air. They are easier to whip around quickly making them great in the air as well as on a wave that lets your perform quick snappy turns.
Jack Freestone coming up for some air on his PU DX 1.
They seem to have a more buoyant feel to them, as if they sit a little more on top of the wave instead of in the wave. This can be beneficial as you can get up to planing speed faster, and it becomes easier to clear through flat sections on clean days. The combination of these factors has made them a great option for small wave boards.
The foam has a more consistent density throughout which allows your shaper to carve out his masterpiece a little more freely without having to worry so much about taking too much of the dense foam away, exposing softer foam under your foot, which can happen with PU blanks.
PU blanks become less dense the deeper you cut, so shapers do have to pay attention to how much they are going to take off especially from the deck. EPS, however, is a little harder to shape out clean compared to PU. The materials are also a little more expensive for the manufacturers which results in EPS/Epoxy boards costing a little more than your standard PU/PE.
Many retail shops you will find the same board model around $100+ more when EPS/Epoxy. Don’t let that scare you off though, that extra cost can very much be worth while.
Epoxy resin (the only resin that can be used on EPS foam) is a little stronger than Polyester. It is more flexible and can snap back into shape better than Polyester which is a little more brittle and can lead to cracking.
But you do need to wait longer before riding your board so the Epoxy can fully cure or else you will be looking at foot wells that form under your feet when surfing.
(Some surfers use this as an advantage, helping to keep their feet locked into the sweet spot)
A demo fleet of Stamps Surfboards almost ready to go.
EPS for the Environmentally friendly
They are more environmentally sustainable than your standard PU/PE board.
Some more than others, but essentially EPS foam can be made from recycled material. Your next flatscreen T.V. will be packed with styrofoam which you can take to many drop off points and have that packaging sent to plants where they break down the styrofoam and repurpose it into massive foam blocks which can be cut into blanks that are just as good as “virgin” foam.
Epoxy resins take less energy to produce, and there are even brands that are finding alternatives to using petrochemicals as their base. Options like tree sap for example, reducing even further the carbon footprint of standard epoxy resin.
Combining recycled foam with tree sap based resin gives you a board that is much more environmentally friendly and just as durable as the status quo.
The manufacturing process for board builders involves less chemicals like acetone, etc. and they almost emit 0 VOC’s in the air compared to their highly toxic PU/PE cousins.
, they are healthier to produce for the manufacturers as well, but with one disclaimer.
They must wear the proper protection as one of the hazards that Epoxy has is the ability for a person to become “sensitized” to some of the chemicals used in the hardener. Once this is in your system is it with you for life and you can have bad allergic reactions to it.
Polyester on the other hand can still make you sick, but with some time away from it you can get it out of your system. So it is highly important to take the proper precautions no matter what construction someone is working with.
But which one’s for you?
There are so many other factors that can be touched on but for our purpose here, we are trying to give you a better idea of which basic construction and attributes you may want out of your board.
This will be determined by what you are looking for in the characteristics of your board. Both options have strong advantages and really can’t be compared when put side by side as they perform so different.
It will just come down to what you prefer in the end.
A rack full of the SUPERbrand Fling model in both EPS and PU/PE constructions.
As most of us can’t afford a large quiver of boards, one really solid option you can consider is looking at having your board made with PU foam and Epoxy resin. This will give you the trusty feel and performance of your standard board, but with the added strength of epoxy resin instead of polyester.
On the other hand, Polyester resin works much better with colors and gloss coats, which can give your board the aesthetic charm that you may be after.
The Panda Surfboards Fried Till You Die in PU construction with a nice resin tint.
Unfortunately, you can not glass an EPS board with Polyester resin as it will melt the foam, so your color work becomes limited except in the best hands, and this can increase the cost.
If you really just need a small wave ripper, the EPS/Epoxy works great as the buoyancy and it’s light weight make it a dream to catch smaller waves and make it a breeze to snap a lot of turns in a tight area.
Essentially giving you a nice light whippy feel.
The most important thing
The end result really is to stay as stoked as possible.
Some people can afford the luxury of ordering many boards and can even have the same model in both constructions to have on hand for them to choose from. The Pro’s, for one, can easily make use of both but the average surfer needs to think a little more about what they want for an all round go to board.
Album Surfboards Ledge model hanging out ready to go.
Our goal is to help inform you so you can make the right decision for your next custom surfboard and make sure you are as stoked as possible.
There is a lot more to go into with Surfboard Constructions and many brands that will use specific glassing techniques depending on what they intend a board to perform like.
From Hydroflex, Future Flex, Carbon Wrap, parabolic stringers, Carbon Vector Net or strips, and many more. Stay tuned to learn more about the different constructions available…
While you’re here check out some other articles on board design to learn more:
Are you surfing the wrong board?
Selecting the perfect surfboard
The Fin Guide
Surfboard Shapes – Tails Rails and Noses
Surfboard Bottom Contours