Wooden surfboards are heavy, like, really bloody heavy. The way I went about it here still weighs a ton, but I think it has legs for another attempt at some point.
SO, when you look at the world of boating, the clever sods have figured out a way of making really smooth complex curves out of wood. I’ve heard it said that a lot of people choose this method as it’s stiffer and stronger than GRP, and cheaper than carbon.
The method i’m talking about is known as Could-Moulding. The technique is pretty simple, where you glue layers of wood veneer over a form, at alternating 45 degree angles. What you end up with is a stiff 3D surface structure. The angled wood veneers give strength and stiffness across all axes. Adding a layer of fibreglass cloth and resin to the finished structure locks it all in and weatherproofs the whole thing.
I had a google and a look around, but couldn’t find any instances of anyone trying to make a surfboard like this. (I’m not saying they don’t exist, just that my low-effort search didn’t find anything.) So, I figured that I would have a pop.
I started with some leftover plywood. With a jigsaw, I roughcut a stringer to the rocker line I was looking for, and tidied it up with a hand plane. For the ribs, I used some thinner plywood, with cross-sections spray mounted as cutting guides. I cut these flush with a pull saw. I cut slots into all of these skeleton pieces, a little dab of glue, and it was ready to figure out how to mount the rails.
The outline needed smooth curves. I glued some thin pine strips to the outside corners of the ribs. With string I lashed it down while the glue cured. For now we can ignore the rails, they can be sorted when the deck and base are both in place.
We have the rough shape of the board now, and enough wood locked in to stick the top and bottom too. the first layer goes on pretty easy. With polyurethane (PU) glue along all of the contact areas, I clamped down the veneer strips. They were cut and clamped over length, then trimmed back with a pull saw.
For the next layer, I had planned to vacuum bag the veneer down, again with polyurethane glue. But. When I was vacuuming a test piece, there was a loud bang, and a lot of smoke.
Vacuuming wasn’t an option anymore. Instead, I got a bit creative with my box of spring clamps, and managed to bodge together an arrangement that just about handled it.
I was a little worried about the ribs being a little too thin. (Rightly so, they were flimsy as fuck.) So I filled the skeleton with expanding foam. This took the load off the ribs, and added some more overall stiffness.
The base went on pretty similarly, but with only a single layer of veneer. As the glue I’m using here is gap filling polyurethane, the space between the expanding foam and the veneer is pretty well dealt with. I chose to only use a single layer as it wouldn’t need to deal with a me-sized lump constantly stomping on it.
Once trimmed, there was some inconsistency with the surfaces and edges. Although this can be tickled with a wood file and an orbit sander before moving on to the rails.
Building the rail blanks is really fun.
To build them I used the same gap filling PU glue from before, and clamped together three strips of 8mm thick cork sheet. Where the sheet width didn’t match the overall board length I just staggered the join lines in the layers.
Once I had the rail blanks ready to go, they were stuck to the sides of the board with the same sticky stuff as before. Clamping was done with some left over pine strip and bungee cables.
When the glue had done its thing, the rails were trimmed flush to the deck with a pull saw and a wood file.
There were some gaps left at this point, both at the joins of the rails, and at some points between the pieces of wood veneer. I made some filler by mixing some salvaged cork shavings with the PU glue.
The rail shaping was the natural progression from this point, and was achieved with just a wood file and sand paper.
The tail block used a pretty similar method as the rails, but as its a pretty tricky angle to clamp to, masking tape proved good enough.
It would be a bit of a stretch to do laminating in the dining room. Luckily, where I work has a big composites tent. The timings worked out that I could sneak in after work and laminate the board in the evenings. Glassing and fin box install was done in the traditional way.
Shortly after finishing it, I took this plank with me on a Christmas trip to Morocco. For the most part, it worked pretty well. But, there were some issues.
Firstly, it’s heavy. That’s not such an issue on the water, but you get sick of carrying it. Secondly, it needs a vent plug. I was concerned about it popping on the plane, luckily that didn’t happen, but I could definitely feel it inflate under the midday sun!
Finally, I didn’t really gel with the shape. Using this method does carry some risks, and cutting the internal structure by hand can lead to errors that can’t be fixed later on. For this project, the main drawback was how thin I ended up making the tail. The board paddled really well, and providing the wave is steep, takes off well. The skinny tail though had a habit of bogging down when the waves were small. I’m going to try again with an evolution of this construction at some point. It works, but there are definitely improvements to be made!
NB. I was rushing to get this thing finished and ready for the trip, but the whole project took around three weeks of working on it most evenings and weekends.
Callum McCullough 