Despite a history that dates back several centuries, modern surfboards are remarkably technological. They start off as delicate pieces of foam, as breakable as a disposable coffee cup, and end up propelling their rider across the face of a churning wave, withstanding the crushing power of the ocean. The trust that a surfer holds in his surfboard under such intense conditions is an essential part of the sport, so it's important to have some idea of its construction and design. Here's a glimpse into the process.
(Most of the following article pertains to surfboards made by hand shapers, though the process is similar even when companies mass-produce their boards using machines.)
To look at a pile of foam slabs, it's hard to believe that such flimsy, brittle material can be fashioned into high-performance equipment capable of taking on the enormous force of a breaking wave. But that's how it all begins – a sheet of foam cut into a brick just a bit larger than the surfboard it will one day become.
Polyurethane foam is the most common material used in building boards, though some shapers prefer to use Styrofoam, extruded polystyrene or expanded polystyrene to make their blanks. Additionally, foam slabs come in a number of densities, thicknesses and weights, with shapers deciding which specifications provide the best foundation for the board they're designing.
Foam slabs become blanks in just a few steps. First, the shaper adds one or more wooden stringers, giving increased strength to the foundation. These stringers are roughly the same thickness as the slab, and are often rounded at the nose and tail to give the board shape and increase its rocker. To insert the stringer, the shaper must first cut the foam lengthwise down the center with a hotwire (a very thin, red-hot cable with a handle on either side). He then glues the stinger in between the two halves and tightens straps around the block of foam to secure the stringer while the glue hardens.
Once the drying process is complete, templates are fastened into mirroring positions down both sides of the slab. To see them from the side, the templates resemble the profile of a kayak: long, narrow and upturned a bit at the end. These provide a guide for the shaper as he hotwires off the excess foam along the top and bottom.
The final step is to attach the "bird's eye view" template to the top of the slab, centered over the stringer. This template, like those used on the sides, is made of a flexible wood that rests flush against the now-concave surface of the board, secured into place using clamps. Running the hotwire along the template's edge, the shaper cuts the foam into the outline of a surfboard, finally turning a simple foam slab into a blank.
As you can see, blanks are not terribly complicated to make, but they are the basis for a lot of the resulting surfboard's integrity and strength.
(To be complete, I'll note that this process varies quite a bit from shaper to shaper. Some people prefer to use saws rather than hotwires, or they'll add extra stringers to the foam. In fact, not all shapers make their own blanks; there are many who prefer to spend their time on the more technical aspects of making surfboards, so they buy pre-fashioned blanks from foam supply companies.)
The art of shaping requires a keen attention to detail and a dedication to progression. Shapers are tasked with transforming blanks from foundational blocks of rugged foam into precisely articulated surfing machines, factoring in design elements to achieve particular performance characteristics.
Shaping by hand demands a throng of tools, a well-ventilated area to work and a good eye for symmetry. To begin shaping, a planer is used to shave off and even out the foam along the deck and base of the board. Many people will start out using a rough setting on their planer, to remove any imperfections or lumps in the foam, before using a finer cut to allow for more detailed tuning. Before moving on, the shaper uses a sanding block to smooth out and refine the surfaces of the surfboard.
The rails come next. To give themselves a guide as they sand, shapers will use a pencil or pen to mark out their "lines" along the sides of the blank, the degree to which they will shape the rails down. The angle of the rails is the basis for the board's turning ability, steadiness and performance, so the measurements must be precise (not to mention identical on either side to ensure balance in the finished product). The nose rails are often tuned to 50/50, meaning the line runs dead even between the base and the deck of the board. As the marking line moves toward the center rails, the tuning eases closer to a 70/30 measurement (where the line is drawn 70% from the top, 30% from the bottom). Typically, the last third of the board gets tuned to 100/0, so the deck is shaped down to the bottom. These guidelines are incredibly subjective, and every shaper has his or her own ideas about the most functional way to shape the rails. Once the line is in place, the shaper uses a sanding block to file down the rails, finishing off with a fine-gauge paper for the final touches.
Last but not least, a small hole is made for the leash plug and the grooves for one or more fin box are carved out. These pieces will be added a little later, during the glassing process.
(This section describes the process used by hand shapers, but there are plenty of bigger companies who have machines that can do most of a board's shaping. Using Computer Assisted Design (CAD) software, these businesses are able to design the shape of the board on the computer, feeding the information into specialized equipment that then cuts the board down to size. There is no replacement for the human touch, however – these boards are still finished by hand.)
The shape has been completed, and it's now time to glass the board. Before glassing, painted graphics may be added by spraying or painting directly onto the board. Cut-out graphics are also added at this point if they're desired.
With the graphics finished, the glasser gets to work. Several layers of cloth fiberglass are laid out across the deck, cut to match the shape of the board, and treated with a hardening agent to give them strength. The weight and the number of layers of the cloth vary depending on the size of the board (and to some degree, the size of the person riding it). Usually, a deck receives two or three layers of cloth – 4oz weight on shortboards, heavier on longboards – while the bottom is layered with one or two sheets. Before any resin is added, the glasser makes cut-outs in the cloth where the fin box(es) and leash plug will be inserted, eventually squeezing them into place after a layer of hardener has been applied.
This is the time to acknowledge the differences between the various foams used in creating surfboards, as different types of foam require the use of different types of hardening agents. When the blank is made from polyurethane foam, the cloth fiberglass is coated with a layer of polyester resin. Conversely, shapers who use Styrofoam blanks glass and coat them with epoxy to give them the durability they need. For a more detailed discussion of epoxy resin technologies, take a look at this article.
The resin adds a lot of weight to the surfboard, so after it dries, the shaper/glasser takes a hand sander and removes a lot of the build-up. While this may seem counterproductive (didn't they just apply the stuff?), the resin has already done its job, seeping into the upper parts of the foam and activating the strength of the fiberglass cloth. The extra stuff on the surface of the board is unnecessary. With the sanding complete, a spray or brush-on finish can be added to make the board look glossy.
After that's done, the fins and leash are put on and it's down to the beach for a test ride!