top of page




The first step in the design process is choosing the correct blank. Most surfboards are made with polyurethane foam (PU) or expanded polystyrene (EPS). A good surfboard can be built using either one or the other. The past few decades have brought new, sophisticated and more eco-friendly components into surfing, or resurrected materials used in the past, but the foam / resin combination remains the most popular choice around the world. We will deal with these two blank options, on the basis of which choice, all other decisions will fall. Our suggestion is to evaluate the pros and cons of all materials, both from an economic point of view, the quantity of manpower and ease of processing and from the point of view of the final product.


Polyurethane Foam (PU) Blanks have been the foundation of the surf industry from the 1960s to the present day. Most PU blanks have a standard density (often various brands PU blanks offer various densities) of 3 pounds per cubic foot, approximately 48 kg / m3, much denser and heavier than Styrofoam blanks (2lb / ft3 or 30 -35 kg / m3), with a smaller cell structure. For this reason, boards built with PU blanks make the ride smoother in less than perfect conditions, absorbing chops and vibrations more effectively than EPS blanks.

The PU blanks are supplied with a wooden stringer already inserted and this saves time both in the processing phase and, as in the construction of longboards over 9 feet, in the search for suitable woods.

Another less concern when working with PU blanks is that the lamination can be done with either polyester or epoxy resin. Normally polyester resin is used as the use of epoxy resin on PU blanks, both much more expensive than their respective alternatives, will lead you to spend a significant amount.

Another feature of the PU blanks that make it preferable in this case to the EPS blank is the lower water absorption capacity. During a session it often happens to break the board, perhaps after bumping it against a rock. Well, with a PU blank you can easily, in less serious cases, stay in the water and maybe continue to use the board even in the following days, perhaps putting a piece with a good American tape. The absorption of water is minimal and you can safely dry the damaged part once the sweel is finished.

From the point of view of the shaper, working a PU blank will be much more satisfying due to the compactness of the foam which makes it pleasant to slide the tools. No cracks or blisters of foam leaving, the surface of a PU blank is firm and hard, and the activity is closer to that of the sculptor. A completely different feeling compared to the processing of EPS blanks, so much so that all shapers can agree in the simple phrase "a real PU blank is a whole other thing !!"

There are also internal differences between polyurethane blanks and polyurethane blanks. There are now many countries where companies have launched blankets for the surf industry. Not all donuts come out with the same hole. Almost all the shapers agree in giving extreme importance to the choice of the blank brand both from the point of view of processing and that of the final result. In processing, an excellent blank has a polyurethane foam formula that is the result of years of research applied to surfing. In addition, the dimensions are fundamental, a wide choice to accommodate the various projects and limit the roughing work. The squareness and precision of the surfaces is a fundamental element, so much so that not everyone is able to have satisfactory results in this sense. Excellent blanks can have different characteristics, some more useful for one purpose, others for another. For example, the hardness of the surface has consequences on workability and resistance to bumps. A good blank must be able to reach the right compromise between these two factors. Within this range, which includes the best brands of blanks, different philosophies are distinguished: those who prefer workability with a wink to the shaper, those who prefer hardness thinking more about the surfer.

The choice of an excellent blank is essential for a handshaper, especially if a beginner, focusing on blanks well made in the shape and formula of the foam, easier to sand and with a large catalog to help save time in working to get to the desired shape. We are proud to have brought the distribution of USBLANKS to Italy, undoubtedly the spearhead among the blanks in the world. Born from the bowels of Clark Foam, Usblanks is ideal for the beginner and for the professional and for the surfer who will take him into the water.


EPS Blanks have also been used in surfboards for decades, but their use was put aside when Clark Foam in Polyurethane Foam was invented. Australia followed the invention so the market was literally diverted to PU Blanks. Never completely abandoned, EPS blanks have only come back into fashion in the last 10/15 years, coinciding with the closure of the Clark Foam factory in 2005 in the American context. Always starting from the USA, the rediscovery of polystyrene as a base for surfboards led to a study of the techniques and benefits that this material could offer to the surf industry. These boards have demonstrated a higher strength / weight ratio than polyurethane, allowing for increased strength and reduced weight. Right now the most popular surfboard brands, Firewire, Lost, Heyden Shape use polystyrene blanks to produce their boards, as well as some of the best surfers in the world, use EPS boards in both freesurfing and racing in the World Tour. Currently the EPS is particularly popular for small-medium wave boards, where buoyancy and weight are important factors, but they are also gaining popularity in big-wave guns and performance longboards, where the drag ratio / weight is very important. Furthermore, a polystyrene blank is significantly cheaper than a PU blank.

The cons of this material were the greater water permeability inside the polystyrene cells, a greater amount of work compared to a roughly pre-shaped clarkfoam and the mandatory use of expensive and "difficult" epoxy resin. It is essential to know that when laminating on an EPS blank (or XPS, we will explain this material to you below) epoxy resin must be used. Epoxy resin is needed as its alternative, polyester resin, contains Styrene, a solvent capable of dissolving polystyrene. Not bad since epoxy resin is much more resistant than polyester resin.

Let's see in the list the main reasons why the EPS / EPOXY combination was abandoned:

1) From an economic point of view, the savings obtained with polystyrene will be entirely lost on the higher cost of epoxy resin, two or three times as much.

2) The epoxy resin is also much more in need of care and "affection" than a polyester. It requires precision and attention in the mix of the two components, greater control of temperature and humidity, long, often very long hardening times, greater protection from dust and dirt. In short, not really an "easy" subject.

3) A polystyrene blank is also more difficult to work, as compared to polyurethane it is more fragile and it is very easy to ruin it with the probable detachment of parts or blisters that will have to be subsequently repaired.

4) Furthermore, the amount of work to be spent in the shape and glassing phase will be greater. The project was obtained starting from a parallelepiped block. A stringer had to be added to reinforce the break. In addition, it should not be underestimated that the epoxy resin has much longer hardening times than a polyester, so that it will be necessary to wait a long time between one processing and the other. All this is absolutely not functional to industrial production.

5) Last and biggest flaw, it is the air space between the closed cell pearls that traps and holds water. By itself, polystyrene of good density would not absorb water. Try to leave it outside during a non-stop rainy day. The problem arises when the polystyrene is closed in a fiberglass "skin". The sensitivity to the change in pressure and heat, caused by the presence of air between the closed cells that make up the block, causes absorption when the board breaks. After absorbing heat on the beach or in the car, contact with colder water and a simultaneous break in the fiberglass coating causes water to be absorbed inside. The more water absorbed, the harder it is to escape, causing weight gain and yellowing.

6) Always linked to the same cause, the thrust towards the outside of the air inside, stressed by the heat, can cause a detachment of the laminate, that is the phenomenon more commonly called delamination. Being a matter of internal / external pressure difference compared to the surfboard, even a trip by plane can be very dangerous.

Another type of polystyrene, or more commonly polystyrene, is Extruded Polystyrene (XPS), produced precisely through an extrusion process. Unlike its similar, it behaves much better with respect to water absorption, but compared to it it is more prone to delamination. This material is also more expensive and difficult to find, although in some construction companies it is possible to find parts according to your needs. Only if you adapt to the available colors and sizes can you save a lot. With this solution the costs will be even higher than the previous two combinations PU / POLY and EPS / EPOXY, since also in this case epoxy resin will have to be used.


We will not give any final judgment on which is the best material, but on the elements on which everyone can evaluate from time to time based on their project. First of all we come to the advantages that the EPS / Epoxy combination has compared to its more famous alternative.

In terms of performance, the board made of EPS / EPOXY will be more resistant and at the same time lighter. The weight / resistance ratio will be so much better than the PU / POLY combination that it will be possible to obtain greater performance while improving resistance at the same time. The weight difference of the final product is evident, thanks first of all to an extremely different foam density. With this type of difference, in the case of an EPS board, you can decide to increase the amount of fiberglass for lamination by increasing its resistance while always remaining below the standard weight of a PU / POLY board.

The lower density of the blank also entails greater buoyancy which in a glassy or slightly agitated situation will give speed and greater glide over the water. This certainly represents an advantage when you need a board capable of giving greater satisfaction in not very demanding conditions, improving ease of rowing, advance in take off, speed in soft sections. But it can also represent an advantage for those who require extreme performance, as it is more agile and light, so much so that the use of Eps boards among the characters of the World Tour is increasingly evident both in free surf and during contests.

The structure of the foam, which unlike fixed cell polyurethane foam, is made up of closed cells fused together in a steaming process, results in a higher elastic and memory quality than PU. Although the research of some brands has led to an evolution of polyurethane foam PU in terms of resilience, making it much more similar to expanded polystyrene, EPS in general is less subject to the phenomenon of crushing.

We have seen the advantages of the EPS / EPOXY combination from the point of view of performance, now we are going to evaluate those from the point of view of the shaper. First of all, the complete freedom to make unusual shapes that would be impossible with an already roughly pre-shaped PU blank. From a polystyrene block you can bring out boards with very wide tails, flat or very high rockers, indulge yourself as you like without having to fit your ideal project into the blanks. EPS unleashes the creativity of any shaper without chaining it to foam industry projects.

One of the advantages of EPS blanks is that they have a constant density throughout its volume. PU blanks are denser and harder on the surface and tend to be softer as you go down to the inner core. For this reason, with the PU we must be careful to stay as close as possible to the pre-shaped mold and then choose the blank well according to your project to preserve the most durable component. If you go too far, it is easier to get dents when using it in the water.

No less important, especially for a beginner shaper or icer, the fact that the epoxy resin has a longer processing time, that is the useful time before the hardening phase begins, which unlike polyester does not happen suddenly, but very gradual. This facilitates the work of those who are beginners, and also involves greater accuracy in avoiding waste of resin to be thrown on the ground. In fact, you don't mess with polyester! You have to be fast and for this reason it is always better to abandon the quantity of resin to be poured, especially during the lamination phase. This results in a lower resin requirement per board when using epoxy.

Another element, which we will mention here only to be taken up later in a broader sense and from the point of view of environmental sustainability, is the low intensity of odor emission, which will avoid you when working in the garage or garden or even at home. a lot of quarrels with those who live close to you.

However, what we have described above is not enough to explain how polystyrene has recovered compared to polyurethane in today's market. As we have mentioned, many of the top brands and surfers use EPS Styrofoam as their blank material. The development of materials and construction techniques have allowed the polystyrene boards to equalize many of what were considered to be deficiencies towards PU, and to maintain instead the advantages of the EPS / EPOXY combination. To explain ourselves better, let's take the points presented above as defects, trying to integrate them by describing the current situation with the evolution of the materials.

1) Higher cost of epoxy resin;

From this point of view, no improvement, epoxy resin, in its most qualitative forms, continues to be much more expensive, eliminating all the savings achieved with the choice of the EPS blank. On the other hand, epoxy resins have had a greater development in the search for a more functional product for the production of surfboards, more effective and less and less toxic.


2) The epoxy resin is also much more in need of care: precision and attention in the mix, greater control of temperature and humidity, long, often very long hardening times, greater protection from dust and dirt.

The continuous research on this material has led to the production of resins with superior quality and closer to the needs of the surfboard manufacturer. Our particular search for the best materials led us to come across the Epoxy Resin produced by Resin Research , an American industry that has absolutely thunderstruck us. Fortunate to be the only distributors in Italy of this fantastic product.

Epoxy Resin Research has very short complete hardening times compared to other epoxy resins, while maintaining reasonable processing times. The latest addition to Resin Research, the Kwik Kick epoxy, further shortens the complete hardening times while maintaining reasonable processing times. At room temperature of 21C °, it has a working time before the hardening process starts of 18 minutes and reaches the solid state after only 90 minutes !!! By increasing the temperature these times are reduced even more !! This means the possibility of building a board in two / three days in summer temperatures. (In winter, however, we recommend heating the environment to optimize the fluidity of the resin). This feature will allow you to build your super tough board in just a few days, just like you would a polyester board. This feature makes it attractive both for the beginner who needs more time to complete the lamination, and for professionals who require shorter hardening times.

Another defect of the epoxy was that of the impossibility of use at temperatures below 20 degrees. It is absolutely not recommended, but the Kwik Kick formula can be used and achieves hardening even in cold temperatures. You won't have to heat the entire room to do a touch-up or repair.

Compared to other epoxy resins , Kwick Kick Resin Research keeps heat production low during hardening, lending itself better than any other resin to the attachment of plugs fins or leashs !!!! Epoxy resins can reach high temperatures during hardening, and in castings it can even melt its surroundings. Kwik Kick reduces this effect, but it is always better to be careful with the shims.

Epoxy resin has always been more sensitive to impurities, often resulting in the release of annoying bubbles or uncovered parts of fabric. Resin Research has developed a particular ingredient that concretely helps to reduce the possibility of these occurring when the resin hardens. The revolutionary Additive F makes the resin easily sandable and free from annoying bubbles caused by impurities !!! An additive exclusively invented for Resin Research and incompatible with other epoxy resins (DO NOT USE ADDITIVE F ON OTHER RESINS! IT COULD CAUSE SERIOUS DAMAGE !!!), which allows to reduce the problems and disadvantages of epoxy resin compared to polyester and to maintain all the advantages in terms of strength, flexibility and workability that epoxy has compared to polyester resin. Additive F makes Resin Research indisputably the most used in the USA and the most desired in the rest of the world.

3) Fragility of the foam and greater difficulty in processing;

EPS blocks are typically available in densities of 25, 30, and 35 kg / m3. Most shapers choose 30/35 kg / m3 blocks, as they are easier to shap while providing a strong yet lightweight board. Lower densities, 15/25 kg / m3 are used in Stand Up Paddleboards. As we have written above, another defect characteristic of EPS compared to PU is the larger cellular structure; this makes it more difficult to shape and obtain completely smooth surfaces. In fact, the surface is more resistant to the tool and often, even when you are gentle and attentive, you can create small holes. To remedy this defect, once the shape phase has been completed, the entire surface of the board can be sealed with a putty by mixing a little resin with ultra-light organic microspheres . This step, not mandatory but strongly recommended, will allow you to have a perfectly smooth surface, which can be painted easily and above all it will allow you to use less quantity of epoxy resin in lamination, as the filler will clog all the pores sealing the blank. The final product will be perfectly smooth and free of cracks and even the annoying visual effect of the polystyrene will disappear.

4) Greater amount of processing in shaping and glassing.

The processing times of the Eps block compared to a roughly shaped PU blank are generally longer. Now it is possible to skip the production and gluing phase of the stringer using Unidirectional carbon bands (or other more ecological materials such as Basalt) which combined with the greater resistance of the epoxy resin will guarantee greater flexibility and resistance to breakage as well as a decrease in weight compared to to the wooden stringer option. If you are not obsessed with wood cores, some material choices can save you effort, weight and money and gain flexibility and performance. You can make car crush proof boards using "S-glass" type fiberglass instead of the more common "E-Glass" in addition to carbon tape instead of wood.

If, on the other hand, you want to reduce the work to be dedicated to extracting the project from the polystyrene parallelepiped, you can ask the polystyrene factory near you for the precise cut of your project. On our site you can take advantage of the opportunity to get your Blank Preshaped already made in outline and rocker profile. In this case you just have to work on the details, that is the rails, the curve of the deck, the concave, tail, channels and everything you want to do on your blank. All you have to do is send us your project made through CAD programs optimized for surfing such as AKU SHAPE or SHAPE 3D and tell us whether or not you want to insert the stringer, and the thickness. You will have skipped the most tiring and "dusty" part (in addition to making well orthogonal surfaces you need good and expensive tools), and you will have to work on the most exciting and original part of the manual shape: the rails, the deck, the concave ones, the tail and possibly channel or other

5) The biggest flaw, the air space between the closed cell beads that traps and holds water.

First of all, the biggest problem (for those who do not use the board professionally) that is the absorption of water in conjunction with a break, remains a great burden for the EPS !! New developments in cell density and compactness decrease the absorption capacity so much that it is no longer a big enough problem to discard its use. The new EPS SUPERFUSED Blanks, derived from a fusion process of EPS cells, further improve resistance to absorption. Nevertheless, the advice remains that if you should have a break during a session, it is still important to go out and use products for instant and temporary repair, such as Solarez Epoxy, FCS Epoxy mastic , or simple American type cloth tape, which you can use perhaps to finish your surf trip or wait for the swell to finish. The advice then is to dry the board well and repair it before taking it back into the water. It is important to carry out a complete drying of the inside of the table, helping you by giving heat to the table and then carry out a repair to perfection. Complete repair kits are available on our site with all the top-quality everything you need to complete the task.

6) Delamination phenomenon.

As we have already explained, in cases of strong heat or pressure changes, the thrust of the air trapped between the EPS cells can cause the laminate to detach from the surface of the blank. This is a very serious problem. Precautions can be taken, avoiding coloring the blank, using sealing pastes that react to water or heat, avoiding dark colors, especially black. All of this lowers the chances, but doesn't eliminate the problem behind delamination.

Extreme variations in temperature or pressure release the release of gases that cause an outward pressure causing delamination. The installation of a relief valve capable of letting air out of the core towards the outside of the table, preventing the entry of water, prevents the accumulation of pressure by uniforming and constantly balancing the pressure difference between the inside of the table and the surrounding environment. The vent works by allowing air and other gases to pass freely through the membrane preventing liquids from entering.

We have so far left out the environmental aspect that we consider very important, but for this it does not mean aligning ourselves with the "strong" environmentalist discourse of the moment which considers everything that is Bio as Eco Friendly. Our Resin Research resin has a high Bio content and is indicated together with a few other resins as a vehicle to receive the now famous rice paper sticker from the ECOBOARD PROJECT Association. Furthermore, EPS is completely recyclable as opposed to polyurethane foam.

But our main axiom is that anything that lasts longer is more Eco Friendly . We do not go into complex and political issues here that would lead to divergences, so let's get back to the concrete immediately.

Epoxy resin, especially in its more recent forms, does not emit those annoying odors that pollute the environment to neighboring neighbors. The use of epoxy resin is almost odorless, the opposite of polyester resin. The latter could seriously annoy people within a hundred meters, especially your mother or father or boyfriend.

More concrete still is the question of worker safety , that is, of those who use the resin. The vapor emission of most epoxy systems is much lower than that of polyester resins. Resin Research are all highly solid and have 1/50 the vapors of polyester resins. Furthermore, epoxy is NOT carcinogenic unlike styrene contained in polyester. The only effect of our epoxy on health is the possibility of causing dermatitis on the skin, which is simply avoidable through the use of good gloves. Another issue is Additive F, carcinogenic and dangerous as it contains Toulene, but the quantity in this case is minimal.

You now have many more tools to decide. There is no advice for everyone, but everyone will have to evaluate for themselves, for their goals and their skills and availability. If you have doubts about the choice, know that you will have to choose if you also want to make a board with your own hands.

bottom of page