How to Build a Hollow Wood Surfboard (with 80 Pictures)

This post comes courtesy of Reddit user Tico20 who did an incredible job documenting his woodworking project of building a hollow wood surfboard from scratch. We’ll walk through the hollow wood surfboard woodworking guide step by step so you can follow along with your own build, or just enjoy the quality workmanship of this build.

Building a high quality hollow wood surfboard from scratch is considered an advanced woodworking project to take on. If you aren’t at this skill level yet this post can be an excellent example and learning tool for you. Additionally, we recommend browsing our other woodworking projects.

9'4" diy bunya pine hollow wood surfboard

Here is the 9’4″ hollow frame wooden surfboard I built spanning over the past 6 months. The following pictures and build guide explain step by step how I built it. Enjoy!

The first step was to make the thin sheets that would be the top and bottom of the board called the skins, these were made of bunya pine cut to be 120mm wide, 7mm thick, and 3m long. I used a table saw to make the appropriate cuts.

All the bunya pine planks were cut and then one side was passed through the thicknesser to get one side perfectly flat. This would be the inside of the board – I wanted them flat so they would have good adhesion to the wood surfboard frame.

Once thicknessed they were glued together to make two skins, one for the top, and one for the bottom. They were laid edge to edge flat on a hollow core door and clamped from the sides with weights put on the middle of the skin to keep them flat.

The glue I used was sikabond techgrip which was recommended to me by another surfboard maker because it is waterproof and is an expanding foam glue so it fills gaps.

There was a fair amount of squeeze-out but this is a good thing and easy to clean up later.

9'4" diy bunya pine hollow wood surfboard

The surfboard skin was roughly cut using a jigsaw to the outer-most dimension of the board with some allowance for future shaping.

9'4" diy bunya pine hollow wood surfboard

Next I needed to build the skeleton which would consist of 14 ribs and one stringer or spine.

These are the measurements I built from, I measured them loosely from a friends board, they show the width, thickness, and height from the ground of the board if its sitting on a flat surface. I added extra thickness to the measurements I took to ensure that the wood surfboard would float.

I found the center of each rib and marked what part needed to be cut out so that they could lapped with the spine.

To build the spine I needed to join multiple pieces to get the length and width of wood I needed so I made this jigsaw joint which is in the middle of the board, later on I reinforced it by gluing smaller piece on either side of it.

Now the slots needed to be cut in the ribs and the spine, this was done with a jigsaw.

The first test fit, a lot of the ribs needed adjusting in either depth or width of slot.

This one i tried to hard to make fit and it split the spine, so i added more reinforcing and corrected the fit of the rib.

All the ribs were fitted to the spine.

Before I glued them in place I needed to make multiple adjustments. To the bottoms of the ribs I added a slight concave which determines the shape of the bottom of the board. Then a slight convex was added to the top of the ribs to give the top of the wood surfboard a slightly rounded shape.

Holes were cut in each of the ribs, these serve two purposes, one, to reduce the wight of the frame, and two, to allow air to move between the compartments once it is fully sealed. Also holes were drilled through the spine to let air flow. Finally notches were added to each of the corners of the ribs which would be a spot for some of the frame to glue onto.

Each rib was glued in place with a square to ensure they were all straight.

This is the table I built to glue the bottom skin onto the wood surfboard, it is special because it follows the length wise curve of the board (called the rocker), and the side to side curve of the board which will be the concave. Also in this photo you can see I added the extra reinforcing for the frame to the notches in the corner of each rib.

Finally I was ready to glue the bottom skin on, the skin was laid on the table and the frame placed on top with glue on every part of the frame. Then spare pieces of wood were laid over the frame and clamped, or strapped on either end, this ensured the skin was pressed evenly onto the frame while it dried.

If you want to build a hollow wood surfboard this is a critical step in the process and precision is key.

The clamps and straps were removed and then the board flipped, this is the result, notice the dip in the middle of the board, that is the concave I’ve been talking about.

This is what it looks like from the other side.

Next up is building the rails which are the sides of the board, usually this is done either with very light weight wood, or they are made hollow using a fancy method called bead and cove. But I’m using just one type of wood and I didn’t know how to do bead and cove at the time so here’s my hacked methods which I wouldn’t recommend unless you’re confident you can wing it.

Using 1cm*1cm sticks that were 3m long I slowly built up the sides, the sticks were thin so that they could fit the curve of the board.

One by one I glued them side by side and then eventually on top of one another to slowly build up the sides.

Eventually they got big enough to reach the top of the frame.

This is what the ends look like. And here’s a few more detailed pictured in case you are wanting to build a hollow wood surfboard for yourself:

Now that they were high enough I planed them down to be flush with the rest of the frame.

I also trimmed the ends at this stage so i could put a nose and tail block on.

This is a solid piece of bunya pine being glued onto the front, the same was done on the tail.

And here is the frame done with nose and tail block installed. This was an exciting moment because this is the first time it actually looked like a wood surfboard.

Then I glued on the top skin using the same method as before.

Now it was a sealed vessel and the shaping could begin.

Here’s where I realized I had made a big mistake; if you’re following along to build a hollow wood surfboard of your own then make sure you don’t make the same mistake.

The rails weren’t going to be thick enough to shape properly so I needed to glue on extra pieces to the side so that i could shape it without worrying about busting through to the inside of the board. This took a really long time to do as I could only glue on one stick at a time and i needed to do 5 on each side.

Once the extra pieces were glued on I could begin shaping the board and give it the rounded edges.

Slowly and painstakingly I shaped the entire board with a palm plane by hand.

Once I was close to the shape I wanted I began using a belt sander with 80 grit paper to smooth out the plane marks.

Once it was fully sanded down to 240 grit I burnt my logo onto the middle of the wood surfboard using a cast aluminium branding iron.

It’s a shark with a hook in it based on the book Tico the Shark Hunter.

Here is is ready to be fiberglassed.

This is how I made the fin. First I made a small panel out of some scraps then I then traced a fin I liked onto it and cut the shape out. I then snapped the end of the fin off intentionally.

This left me with a gap at the top which I would be able to fill with resin so that I would have a somewhat clear half of the fin. I made this little mold out of painters tape and slowly built up the fin with layers of fiberglass and resin.

I accidentally snapped the very bottom corner off as i took it out of my mold.

After giving it a sand it looked pretty cool.

I tidied it up a bit and added some more resin to the bottom to fill in the gap. I then sanded the whole thing flat and then began to shape it which is called foiling, in that it is giving it the profile of a wing: fat at the leading edge and then slimming towards the back. Once this was done I put another layer of fiberglass over the whole thing this time.

I trimmed the fiberglass back.

Then I sanded the edges down to neaten them up and the fin was ready to be glassed onto the board.

I got the supplies from a local surf shop called Thomas Surfboards, the guys there were really friendly and helpful and ended up giving me 10L of poly resin with catalyst and wax in styrene, and 20ft of 6oz fibreglass for $230.

I laid the cloth out over the board and made a tape apron around the bottom, now I was ready to wet it out. It was very helpful to have an extra pair of hands at this stage.

This is how it looked after the laminating coat, this coat is simply to fill in the weave of the fiberglass and attach it to the wood of the board. There isn’t any wax in styrene in this mixture as you dont want it to go really hard, by not adding it it essentially isnt fully cured and therefore can chemically bond to the next layer of resin that gets put down.

Next the top side was laminated.

Once the whole thing had a layer of lam resin on i could make all the little modifications that are needed for a board. Because this is a hollow wood surfboard the air inside needs to be able to breath so it needs a vent, which in my case will be a nut embedded in the resin with a bolt and O ring to seal it. So I drilled a hole in my perfectly good board.

I then place d the nut in the hole and filled the hole in the nut with blu tack so that I could resin over it and then pick out the blu tack leaving the threads clean.

The next step to building a hollow wood surfboard was to attach the fin, I had no idea where to place so I called up my friend and asked him to measure his board and then placed it roughly in the same spot.

roving fiberglass for wood surfboard

To attach the fin I needed roving which is long single strands of fiberglass, you can buy it or pull fiberglass cloth apart, it takes a while but it saves having to spend more money when you already have the cloth.

The roving was soaked in a pot of resin and then laid around the base of the fin, then on top of that small patches of fiberglass cloth were laid over to add more strength.

I also added a legrope loop to the tail. I did this by putting a pencil covered in painters tape on the board and then laying roving over it. Mine turned out too thin and when I went to reinforce it it snapped completely so I ended up grinding it flat and then putting a small lump of wood there and layering it over with a small patch of fiberglass cloth and resin which has held up well.

resin and fiberglass layer on diy hollow wood surfboard

I then tidied up the roving once it was set as well as lightly sanding the lap of glass all around the side. Then i could do the hot coat which is just a thick layer of purely resin, no fiberglass.

wood surfboard resin layer

This was done for both sides.

I then needed to sand all the little bumps out of the hot coat which I did with 120 grit sandpaper. In a few spots I sanded through to the fiberglass underneath and needed to patch these area, so i put little borders around them and just put enough resin to cover the little patch.

attaching a wood surfboard fin with fiberglass roving

I did the same for the fin which made it a lot smoother and the base a lot nicer.

sanding a hollow wood surfboard

Finally I could begin working my way through the grits, I went 120, 240, 320 wet, 600 wet, and 800 wet, which came out with a very nice glossy finish.

wood surfboard on roof of car

Time to test it out!

bunya pine hollow wood surfboard sticking in sand with wax

All waxed up and ready to go.

upside down hollow wood surfboard in water

It has a load of imperfections and it doesn’t ride all that great but its the only board I’ve ever owned and I love it to bits, I’m learning a lot about surfing with it and I learned even more about woodworking.

two surfers with wood surfboards on rocks
man surfing on wood surfboard
wood surfboard with wax
man surfing on homemade surfboard

If you enjoyed this post on how to build a hollow wood surfboard then be sure to check out our other woodworking projects and build guides.

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