Ever since making my own SUP this winter, I’ve been asked quite a few times to write an article explaining the basics of how to build one. First off, I’m not a professional surfboard maker, actually far from it. My techniques and materials that I used are not ‘industry standard’ but tend to work really well, regardless.
Having surfed for years when I was younger and being an active whitewater boater, taking up river SUPing came kind of natural to me. A problem I was having with the normal SUP boards that I was using was they were too long and didn’t have enough rocker in the nose to keep the nose from pearling when surfing our local play wave. I’ve used the Badfish River Surfer and found that to be too unstable for downriver use. What I wanted was a short, fat and stable board with lots of rocker in the nose; one that would be great for surfing and also able to run rivers with. You can modify the info here and easily make your own flat water board.
Okay, Lets get down to the nuts and bolts of what you’ll need.
I used regular 2″x2′x8′ blue foam insulation foam from Lowes to create the lump of foam from which I carved the SUP. It runs about $20 a sheet and I used 8 sheets.
While you’re buying the foam, pic up a few packs of this fiberglass cloth. I used a thinner and much more expensive cloth, and wish I would have used this cheaper and thicker version.
I use West Systems epoxy resin when I fix and modify fiberglass squirt boats. It really is a great choice, and the metered pump system makes it super simple to get the correct resin to hardener ratio. I prefer the 205 Fast Hardener, which works better in colder climates.
I sourced my 8.5″ fin boxes and leash plug from www.FoamEz.com, which is an online supplier of surfboard manufacturing parts.
A really important feature to include in the building of your SUP is a vent so that pressure, from either an altitude change or simply the air inside the board expanding due to heat from the sun, can escape. With the multiple layers of foam used in this project, I recommend using a vent near each end of the board.
After getting your parts together, the first step is gluing all of the foam panels together, I used epoxy resin for this. Since most surfboards use a center strip of wood, called a stringer, to give the board stiffness, I staggered the centerline of each layer of foam so that there wouldn’t be a shear line. This also gave the board a sort of stringer caused by the concentration of epoxy along the offset centerline joint. I stagged each layer 5″ off centerline.
Once you have your big block of blue foam, now’s the time to cut away everything that doesn’t look like a SUP. For me, this was the fun part. After measuring and marking the actual centerline of the foam, I used a large piece of cardboard to create a template for how I wanted the side profile to look. After scribing this profile on one side, I flipped the template and made an identical profile mark on the opposite side.
Trimming the block is a messy affair, with little blue pieces of foam getting everywhere. Know this beforehand and plan on spending quite a bit of time cleaning up. A Shark Saw worked great for making these rough cuts. To create the details and smooth out the edges, I used a sureform type rasp and a belt sander with medium grit sandpaper.
After you design the board how you want, you’ll need to test float it just to ensure that your creation will float the way you want. I went out of my way to ensure that I wouldn’t be soaking the foam when I test floated it in the pool. Little did I know at the time that the blue insulation foam actually doesn’t absorb water and I ended up wasting a bit of time and effort with plastic wrap and tape.
With a few tweaks after the test float, I fiberglassed the entire board with 6oz glass and the West Systems epoxy mentioned above. A cool thing about epoxy is you can dye the epoxy mix just about any color you want. I had an abundance of black dye on hand, so the board ended up black. I’d suggest going for a lighter color to decrease the amount of heat build-up inside the board from the sun.
Halfway through glassing… bottom done, now for the top. I layered the fiberglass from the top and bottom glass sheets to double the fiberglass thickness on the sides.
To give this whitewater SUP board the strength and impact resistance that I desired, I decided to use pickup truck bed liner as the outer layer, over the fiberglass. The cheap spray on bedliner, available at Autozone, comes in either black or tan. After three thin layers of bedliner, I went out for another float test, this time on Crystal Wave.
The surf test went great and I really enjoyed the SUP on this little wave. The nose rocker really helped prevent the nose from pearling and pushing me off the wave.
Knowing that I was going to use this board quite a bit on shallow rocky rivers in Utah, I decided to bite the bullet and have the bottom and sides professionally Rhinoliner’ed. It cost approximately $250 for this to be done, but it was well worth it. I left the top with the thinner spay on bedliner, to keep it as light as possible.
With the board completely solid, It was time to add the bits and pieces. In the normal flow of surfboard building, the fin boxes, leash plug and vents are installed prior to the glassing process. I actually decided to install these after I had already glassed the board, so I had to retrofit them. There are instructions on the FoamEz website for both pre and post glass installation.
I designed my board to be a twin fin, with a permanent center fin. I stepped up the rear portion of the board so that the fins would not be hanging below the depth of the center of the board, which will help protect them from rocks. I went with two types of fins, the nubs shown above and flexy dolphin fins for deeper water, shown below.
The larger fins really lock it onto the wave while the smaller nub fins keep it loose yet help with tracking. After installing the fin boxes, vents and leash plug, it was time to add the traction pad.
I sourced this rasta traction pad from Backcountry.com, a local online and retail dealer of all things outdoors related. In the above pic, you can see the vent hole (and the plug removed) in the red section, a SUP carry handle mounted where the yellow and green pads meet and a chunk of minicell foam behind the stomp pad. I use the foam block to stand on, when I have the rear of the board submerged during a stern squirt. It works really well for that and the rear vent plug is located just to the rear of that. If you look closely, you’ll see the leash plug at the very rear.
The final Product..
Although this isn’t a detailed how-to article, I hope that if building your own SUP is something you’ve considered, this article will motivate you to give it a try. There’s nothing like paddling a board that you’ve created.
If you have any specific questions, please feel free to contact me using the contact info listed below.
See you on the river!