Camber Surfboards are available in a variety of materials and construction technologies. Every material combination has certain strengths and limitations in terms of weight, durability and price. A lighter board will have a lower rotational inertia (swing weight) and change direction more quickly and easily. However, each pound that is taken out of a surfboard is exponentially more expensive because it must be replaced by stronger, lighter materials. The best choice is a balance between your budget and material performance. You really do get what you pay for. Here is some background to help you make an informed decision.
Polyurethane Foam / Polyester Resin
PU/PE has been the industry standard for many years. It is the undisputed favorite of shapers because it is easy to work with. It is also the least expensive alternative at about $100 less than a board made from EPS foam/epoxy resin. From a durability standpoint, polyurethane foam is good so long as an appropriate density is used. If too light a density is used, the cells are friable under load which means they crush and do not return to their original shape which leads to dents in the deck. When the board bends under the rider’s weight, the fiberglass skin on the deck experiences compression loads along the length of the board. The deck of a surfboard should have a smooth surface to effectively withstand these loads. Dents in the deck create an undulating surface which poorly transmits the loads. That is why a new board with no dents in the deck has a nice crisp feel whereas a board with dents feels mushier and mushier as more dents appear. In summary, polyurethane foam at a proper density laminated with a reasonable weight cloth is a good alternative at a reasonable price point.
EPS Foam / Epoxy Resin
EPS foam has slightly higher compression strength than polyurethane foam of the same density. One of the primary differences between EPS foam and polyurethane foam is that EPS foam is resilient and returns to its original shape so long as the EPS is not overstressed under load. Over time, after many cycles of applying pressure, EPS foam with single skin lamination (not sandwich construction discussed below) may also succumb to pressure dents and the board will start to feel mushier and not as crisp as it was originally. Epoxy resin is stronger than polyester resin but a stronger resin alone in single skin construction will not prevent deck dents that degrade performance. The two basic trade-offs for an EPS/Epoxy board versus a PU/PE board for a slightly higher cost are (1) the EPS/Epoxy board can be the same weight as the PU/PE board but slightly stronger, or (2) the EPS/Epoxy version can be lighter than the PU/PE board but it will have the same strength as the PU/PE board.
Wood is beautiful. If you like the look of wood, by all means get a stringer. However, there is a reason why there is no wood on a Formula One racecar, a Boeing 747, or on an America’s Cup race boat. Wood is a relatively low tensile material and is not very efficient from a strength-to-weight ratio. In order to build the lightest, strongest structure, the goal is generally to place the strongest/stiffest materials as far away as possible from the neutral axis.
If the weight of the stringer and glue line is eliminated, that weight can be put back in the skins with a thicker glass laminate, which is important because resistance to dents is a function of laminate thickness. Stringerless construction has been mentioned over the years as a way to save weight or increase flex. Our approach is just the opposite because our goal is to take all the unnecessary weight out of the center of the board and use the weight savings to make the outer shell stronger where it is the most effective. By removing the stringer, we can take the weight savings and use a heavier laminate so the board retains that crisp new feeling longer, unlike a board with a dented deck that has a less effective load path and feels mushier and mushier as more and more dents appear.
Stringers have traditionally provided laminators with a method to maintain rocker on the glassing racks. The use of a rocker jig and a little extra attention during laminating insures that the designed rocker will be maintained.
A stringerless board with a thicker laminate will be less prone to denting. However, in single skin construction it is difficult to completely eliminate heel dents without going to a much heavier blank and laminate schedule.
All of our personal boards are made using sandwich construction. They are 20% to 30% lighter than a single skin board but are significantly more labor intensive to build and incorporate aerospace grade materials. However, once your ride one, you will never want to go back. The increased cost is offset by far greater durability. Ask your retailer to see a Camber Surfboards sample. Custom order only.
When Clark Foam closed, Doug and Scott started working on sandwich structures that took advantage of Scott’s Master’s degree in engineering and Doug’s sandwich structure experience building ULDB’s at P Squared. We built numerous test panels to try various combinations of laminate, resin and sandwich core. Dozens of boards were built and were weighed at each stage of construction.
Sandwich construction entails using the lightest possible core on the inside that is covered with proprietary high strength skins. EPS foam is clearly superior for superlight interior cores, because it is resilient even at the lightest densities so long as the load is spread appropriately by high efficiency skins. Marko’s pressure molded super-fused EPS blanks prevent water from migrating between the beads if the board is dinged. In summary, the weight is taken out of the inner core, and put in a high performance shell that efficiently spreads the load so that it can be absorbed by the inner core without failing.
Choose a material combination that is within your budget, but make sure the foam and glass are heavy enough to last a reasonable amount of time.