Build a Hollow Wood Surfboard

Building a Hollow Wood Surfboard

Hollow Wood Surfboard Build
The Hollow Redwood Mini-Simmons Surfboard

Building a hollow wood surfboard can be a good first step into exploring alternative surfboard materials and manufacturing processes for yourself.

Making a hollow wood board yourself also gives you a better understanding and appreciation for some of the really, really nice wood boards you can find online, on Instagram, or out in the water.

There is some serious craftsmanship that can go into these things that results in a piece of art that you can surf.

You don’t have to go crazy though – you can make a fairly decent looking hollow wood surfboard fairly simply.

Success or failure of your first wood board really comes down to planning, measuring, patience, and sanding.

This page will serve as a guide to building your own hollow wood surfboard as I recall some of my experiences with it.

These steps assume you want to build one from scratch – no kits, no guides, nothing – just your imagination, a little prep, some lumber, some tools, and some time.

There are plenty of hollow wood surfboard kits out there – they typically contain either all or some of the following:

  • Print-out templates
  • Pre-cut spine and ribs
  • Pre-cut bead/cove rails
  • Fiberglass and resin
  • Venting hardware

Chances are you’ll need to source most of the wood for your deck and bottom yourself. Some good choices for a hollow wood board include:

  • Redwood
  • Ceder
  • Pine
  • Paulownia
  • Balsa

What is a Hollow Wood Surfboard?

I covered this a bit before on my overview of the different types of wood boards, but as a quick recap:

A hollow wood surfboard describes a board that’s planked on top and bottom over an internal framework.

For me, it didn’t really feel like I was shaping a surfboard until all the wood was glued together – up until that point, building a hollow wood board felt more like putting a giant puzzle together.

I guess that’s the biggest disclaimer before you jump into it – making a hollow wood board is a completely different feeling and process than shaping a foam blank or even a chambered wood board. If you’re interested in that sensation, building a hollow wood board might not be for you.

That said – your first hollow wood surfboard is probably going to be a little heavy and a bit clunky to surf, but it’s going to look pretty cool, you’re going to be real stoked about it, and once you’re able to figure out how to surf it properly, it’s going to feel like nothing you’ve experienced before.

Materials & Tools for Building a Hollow Surfboard

You don’t need a whole lot to build a hollow wood board – in fact, for your first time, I’d recommend keeping it as simple as possible.

The materials list for your hollow board consists of:

  • ⅛” or ¼” thick plywood for the internal frame.
  • ¼” thick x 1”-3” wide wood planks for making the deck, bottom, and rails.
    • The wood you use doesn’t really matter as long as it’s relatively light and pliable.
    • You can usually find some 8’ redwood planks in the lumber or outdoor section of your local big box hardware store – it’s the kind used for garden borders and such. This is what I used for my first board.
  • Waterproof wood glue.
  • Fiberglass cloth.
  • Fiberglass rope.
  • Epoxy resin.
  • Vent – (screw, brass thread insert, o-ring).

The tools you’ll need are a little open to interpretation, but I used:

  • Computer and printer – to design the board and print the frame template.
  • Jigsaw.
  • Bandsaw or table saw.
  • Router table.
  • Iron – for steam-bending rails.
  • Belt sander.
  • Planer.
  • Variable speed sander.
  • Sandpaper.
  • Lots and lots of clamps. – Bar clamps of various sizes as well as spring clamps of various sizes. Pay a visit to Harbor Freight.

Step 1: Designing Your Hollow Wood Surfboard

Planning and prep is the name of the game when it comes to building a hollow wood surfboard.

The more accurate your templates and measurements, the easier your board is going to be to put together.

The design step can be as simple or as complex as you’d like. On the simple end of the spectrum, you could search online for some pre-made templates or you could buy some plans.

On the more complex side, you could design the board and internal frame by hand.

I settled for something in the middle – I borrowed some dimensions from an existing surfboard design (a Mini-Simmons shape), designed it using BoardCad, and made a template with a javascript program.

BoardCad is an open source cad/cam program made specifically for designing surfboards.

For my purposes, I had some dimensions in mind for my hollow wood board, used an image of a Mini-Simmons to help guide the outline, and then I fumbled my way around BoardCad by dragging control points and adjusting curves until I got something close to what I was imagining.

I found it a bit clunky my first time, but it seems like a pretty versatile software once you get the hang of it.

Once you’ve got your outline and rocker design in BoardCad, you just need to save it.

Next, I found a link to download a javascript program designed to take a BoardCad file and make the rib and spine pattern for the internal frame on an old Swaylocks thread.

The key is to remember to add cross sections to your BoardCad model where you want your ribs to be. In my experience, I think you need less ribs than you think you do.

Run the Hollow Wood Template Maker program, get a PDF of the results, and print them out on a million pieces of paper.

Carefully cut and tape your templates together – keeping track and labeling as necessary.

For the notches, you’ll want to make sure they are deep enough in the spine so the rib sits flush with it. And you’ll want them to be the width or the plywood you’re using or just a hair thinner.

Other things to keep in mind when designing your hollow wood board:

  • The wood you use for the deck and bottom are going to add thickness.
  • Wood is heavier than foam – maybe you want to thin out the thickness of the board to cut down on weight.

Step 2: Preparing Your Wood

This step can either be tackled at the start, so you can just worry about assembly and finish work, or you can prep your wood as you go.

First, you’ll need to cut out and get your internal frame ready for gluing.

If you’ve got a large format CNC router – you can turn your template into G-code and automate the template cutting to ensure accuracy.

But, you can also get away with cutting out your template with a jigsaw.

Once you’ve got the spine, which dictates the board’s final rocker, and the ribs, which will form the rails, clean up your edges and ensure the ribs fit in the notches.

Drill or cut some relief holes in the ribs and spine to cut down on some weight and ensure there will be airflow to and from each section of the internal frame once it’s all glued up.

For your deck and bottom planks, you’ll want to clean them up a bit with some sanding and make sure the edges are straight and flush.

Lay out the boards in the order you want them and make some rough cuts to size them to the final outline – leave them a little bigger than they need to be.

On the bottom, you can get away with wider planks. On the top, you’ll want something small enough that it will be able to bend to both the rocker and rail contours.

Once the bottom and top planks and cleaned up and straightened you can label the order you want them in and set them aside.

It can be helpful to pre-bend the planks so they don’t fight the rocker when you glue them. You can do this with gravity by sitting them on the rungs of a step ladder.

For your rails, you’ve got some options.

  • You can do solid rails once the deck and bottom are glued up. This is achieved by gluing up square planks thick enough on the sides of the board and then shaping the rails afterwards.
  • You can do block rails, by building up ¼” x ¼” square strips around the rib outlines and cleaning them up as you go.
  • Or you can do bead and cove rails, which is often how wooden canoes are built. You’ll need the proper router bit and a router table.

I went with the bead and cove rails. If you’re doing block rails, the prep is the same.

hollow wood surfboard rails methods

You’ll need anywhere from 20-40 long, thin strips of wood for your rails. A little bigger than ¼” x ¼”.

You’ll either need to find wood strips of this size, or you can resaw your redwood planks on a bandsaw or table saw.

To re-saw your wood, you’ll need to set up a fence on your bandsaw or table saw and rip your wood through until you end up with enough strips.

Set up the fence so you wind up with strips of the proper thickness – you’ll need to account for the width of the blade when you’re measuring and setting things up.

That’s pretty much it as far as prep goes. This can often be the most tedious, repetitive, and labor intensive step in the entire process. If you feel your attention wandering, take a break.

Step 3: Building the Internal Framework

Hollow wood surfboard spine and rib table

To build the internal frame, I first set up a table with pegs where I temporarily glued the spine to float above the surface. The spine and ribs remain here until the bottom is glued up.

You’ll want to square up a center line and glue little blocks of wood around each rib location that will hold the spine and ribs as you glue them up and add the bottom planks.

Once the blocks are in place, you can hot glue or drill your spine in place.

From here, you’ll start gluing up the ribs.

You’ll want to make sure they remain square as the glue up.

Do a dry run first to get everything in place and check where you’ll need to block or clamp to keep the ribs square to each side of the spine.

Step 4: Building the Decking, Bottom & Rails

Gluing up the hollow wood board

With your internal frame glued up, you can begin the planking process.

The general process goes like this (if you’re using block or bead and cove rails):

  • Glue up all the bottom planks.
  • Remove the frame from the block supports and flip it.
  • Glue up the rails.
  • Glue up the deck.

It’s not too difficult, but this is going to take a long time.

Gluing the Bottom

Your hollow wood surfboard now starts to take shape.

To glue the bottom planks:

  • Glue your center plank first – this will ensure everything sits where it needs to and stays straight.
  • From there, you can glue up two planks at a time – one on each side of the center plank.
    • The first few rounds are easy – you’ll have plenty of room and surfaces to clamp to.
  • You’ll want to glue on the spine, ribs, and mating edges of the planks and ensure all of these surfaces are clamped snugly as the glue dries.
  • As you get towards the outer planks, you’ll need to get creative with your clamping – you may need to weigh things down with concrete blocks or sandbags – whatever you’ve got on hand.

Gluing the Rails

Hollow wood rails

Once the bottom it glued, you can disconnect from the table blocks and flip the board over. It should feel pretty sturdy at this point. Take the time to clean up any glue drips from the underside of the bottom – you’ll gradually lose access.

To glue up your rails:

  • Start with a guide rail on both sides.
    • Make a notch in the bottom of each rib so a square strip will sit flush all the way around the outline of the board.
  • You don’t need a continuous strip of wood anywhere on the rails – especially if you have any tight corners in the nose and tail.
    • As you’re building up the rails, you can butt shorter strips together to make your way around.
  • Add your first rail – it should be glued to the guide rail and the underside of your bottom planks.
  • Lots and lots of spring clamps of home-made PVC pipe clamps are necessary here.
  • Continue building up rail strips and keeping things clean as you go.
  • As you get to tight curves and as you near the top, you’ll likely need to steam bend the rails.
    • Heat up an iron, get a damp cloth, and hold it against the rail you want to bend. Go slow, glue it up, and clamp.
  • As you near the top of your rails, you’ll need to start creating a flat surface that the edges of the board’s deck will eventually glue to.

Deck Planking

Remember, once the deck is glued up – you can’t get into the interior of the board any more. It’s a good time to make sure you’ve cleaned up all the glue you wanted to and get rid of any sawdust or stray wood chips. Otherwise you’ll have little things rattling around in there.

Gluing the deck proceeds the same way as the bottom.

Start with the center strip and glue two strips at a time on each side after that.

Clamping is a little more difficult on the top than the bottom.

Step 5: Clean Up & Sanding

At this point, if you’ve kept your patience and interest in the project, you’ve got yourself something that resembles a surfboard! Woohoo! You’re in the home stretch now.

Take your time planing down any high spots, making sure mating edges are level, and sanding things smooth.

A block planer, belt sander, variable speed or orbital sander, and sandpaper will come in handy here. Start with 80 grit if things are really rough and work up through there.

Keep an eye out for high spots or low spots.

If you have any gaps or holes, fill them with small pieces of wood and glue and clean up the patch with sanding.

Installing the Vent Hole

Make your own hollow wood surfboard vent
Hollow wood surfboard vent

A hollow wood board built like this should be vented.

External temperature is going to cause the air pressure inside the board to expand if it’s hot and contract if its cold.

Hollow wood boards should only have their vent closed shut when they are in the water – otherwise, leave the vent open and allow it to breath.

You can buy a vent online or you can make your own.

To make your own hollow wood surfboard vent:

  • Find a thread insert and a hex or thumb screw that will sit flush in the insert.
  • Grind a slit or notch at the bottom of the screw.
  • Add an o-ring to the screw.
  • Drill a hole near the nose of the board so the insert can sit flush with the deck.
  • Set the screw aside and tape the insert’s hole shut.

When you’re ready to fiberglass the board, you’ll put some epoxy in the hole around the outside of the insert and around and flanges near the top. Do not get any epoxy inside the threads.

Step 6: Fiberglassing & Sanding

Fiberglassing, hot coating and sanding proceeds just like any glassing job.

Layout your fiberglass cloth and cut. I went with 2 layers of 4oz on top and 1 layer of 4oz on the bottom.

Do a cheater coat of epoxy on the wood before you lay your glass down.

Glassing on Fins & Leash Loop

Before you’re ready for the hot coat, you can glass on your fins and a leash loop.

Again, these steps follow just like any type of surfboard. For the fins:

  • Tack your fins in place with some epoxy.
  • Add some glass rope extending slightly around each side of the base.
  • Cut some fiberglass that will extent around each side of the base and around the template of the fin.
  • Glass it up, let it cure, clean it up with some sanding.

To make a leash loop:

  • Cut and combine a few lengths of glass rope so their about 4 inches or so.
  • Cut some fiberglass cloth patches.
  • Wet the glass rope and shape it into a loop – you can use a pencil or something to help hold the shape as it cures. Just remember to remove it before it fully cures.
  • Flare out each ends of the rope and lay down a patch of cloth over them.
  • Let it cure and clean it up.
Hollow wood surfboard leash loop

At this point you’re ready for your hot coat and final sanding.

Step 7: Surfing Your Hollow Wood Surfboard

After all that time – days, weeks – however long it took, you’re now ready to surf your creation.

Mine turned out a lot heavier than I expected. But I was pretty happy with how it looked.

It’s time to wax it up and tighten the vent.

The first paddle out is exciting – you’re really curious to see how it will surf, but you’re also wondering if it’s going to be watertight.

It takes a bit of getting used to. You’ll need to adjust to its weight and figure out how its rails like to behave.

For the most part, my first hollow wood board was a total dog. But after a few waves, I was starting to get a feel for the take off and lines it took best.

It’s a pretty great feeling to surf something you made – and really gets you thinking about how different design elements come together to perform in the water.

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