Surfboard Build Log

Intro

Ever since I was in high school, I've wanted to build my own surfboard. I've never had the space, and back then, I didn't have the money to buy tools and supplies, either. But I'm 29 now, and thinking about surfboard design a lot lately had rekindled this idea. I decided I'd make do with what was available. I bought the tools, borrowed a friend's garage, and got to work. This is my first surfboard. It's a 5'10" thruster built from Marko EPS foam and Resin Research epoxy. The build took place in August and September of 2010.

Building stands

The first thing I needed for this project was somewhere to work. I found a design for some stands online somewhere and built something similar. These stands are really pretty straightforward, and anything close will probably work fine. One tip -- if you're anchoring your stands in buckets with cement, a single 80lb bag is plenty for both stands. I put an 80lb bag in each bucket and it just makes these things a huge pain to move around.

Designing the board

I needed to design the board I wanted to build. I largely based this board on two existing boards I owned, made some measurements, and went to work in Aku Shaper. Aku Shaper is a really easy-to-use CAD application specifically designed for making surfboards. It's free, too, which is nice, and the files it outputs are compatible with most electronic shaping machines. Here's a PDF file showing the board I designed. It's a 5'10" x 20.25" x 2.5625" (9/16) thruster. The actual board probably came out slightly off from those numbers, but should be pretty close.

Shaping the board

I admit, I cheated here. Some people don't think it counts to use a shaping machine. That's fine. Personally, I'm more concerned with getting the board to come out the way I want it, and I don't see any reason not to use the best tools currently available. Those tools are electronic shaping machines. Cutting boards with planers will eventually go the way of the typewriter.

Anyway, I had Matt Ambrose of Ambrose Industrial Surfboards out of Pacifica cut my board from a Marko EPS blank. It came out pretty decent, needing just some finishing work. The picture here shows what the board looked like straight out of the shaping machine:

At this stage, the board still needs some finishing. I did all this work with a sanding screen on a soft sanding block. After maybe half an hour or so, the board was ready to go and looking like this:

Installing Fin Boxes

The next step was to install fin boxes. I chose to use FCS Fusion boxes because I like the idea of installing them under the glass, and there are certain things I don't like about Future fins (unused fin boxes leave giant holes in the bottom of the board, fins can't overhang the front or rear of the box). I know there are other fin systems out there, but FCS and Future are the easiest to find fins for, and I didn't want to make my life difficult.

Using FCS's installation kit for the fin boxes was pretty straightforward. I routed three holes into the bottom of the board.

Then I mixed up three ounces of epoxy/slow hardener to set the boxes in place. This is about ten times more epoxy than is needed for this job, but I find mixing smaller quantities than this to be difficult to do accurately. I could probably do a better job of not wasting resin here if I had some smaller mixing cups. I had to borrow some fins off my neighbor's board to use to set the boxes, because I didn't actually own any FCS fins I could use. This is what the boxes look like set in the board:

At this point I also signed the board. This really is inconsequential in terms of getting a board built, but I was pretty proud to be signing my first ever surfboard.

Glassing The Bottom

It seems that glassing the bottom of boards first is standard procedure. I'm not sure why this is, it doesn't seem like it'd make much of a difference if you did the top first, but I stuck with tradition and started with the bottom. I was using a single 4 ounce layer of glass on the bottom of my board, so I rolled out some fabric and trimmed off the excess so I left about an inch of overhang for wrapping the rails. I also made sure to cut notches at the sharp corners of the board so I could fold the glass over onto the deck. I also had to put little stickers over the holes in the fin boxes. Don't forget this step or you'll end up with fin holes full of resin.

I mixed 18 ounces of resin/hardener to do the bottom with. The lamination went pretty well, but I did make one mistake -- instead of pouring all my resin onto the board right away, I poured a little at a time and then rolled it out. The problem here is that my bucket of resin got pretty hot and started to kick early. You can see a lumpy spot along the rail on the far side of the board in this picture:

That spot is there because I hit the board with the roller after the resin in my bucket had started to gel. It turned out OK. I ended up mixing six more ounces of resin to finish off the job. The resin on the board itself hadn't actually kicked yet, as it wasn't concentrated in a bucket, and everything mixed together fine. The lumpy spot would be easy to sand out later.

As you can see in the above photo, the lamination coat went on pretty thin. You can see the weave through the resin over pretty much the entire board. This tight lamination is actually ideal, but since I needed more resin over the glass to be able to sand it, and it was too early to flip the board and laminate the top (I don't like to sand epoxy for 24 hours after pouring it), I figured I'd just add a fill coat to the bottom and let it cure overnight. As soon as it was cured enough, I taped off the edge of the board to avoid getting drips onto the deck, mixed up 6 more ounces of epoxy/hardener, and brushed it over my lamination coat. With the fill coat on, the bottom of my board looked like this:

At this point, I let the board sit overnight to cure.

Glassing The Deck

After letting the board sit a couple days (I couldn't work on it everyday, I have a regular job), I came back to it ready to start on the top. The first thing to do was flip the board over and see how the edge of the bottom lamination looked.

I sanded off the little rough spots around the nose and tail, and where the edge of the cloth had wrapped towards the deck. Basically I just got everything fairly smooth so the deck glass would lay over it nicely with no weird lumps or bubbles or anything.

I laid out two layers of glass over the deck. I cut the overlap on the bottom layer pretty short, and the top layer about the same as I'd done for the bottom of the board. The reason for this was I figured it'd make the glass blend more smoothly into the bottom of the board if it went from two layers to one and then none, rather than straight from two to none. Also, I made the bottom the shorter layer as I figured the top layer over it would help keep the cut edges from coming apart while I was flattening it out with the roller while glassing. Here's what the two layers of glass looked like laid out on the deck:

At this point, I also had to add the leash plug (actually, I did this before I laid out the glass, but I forgot to write about it then). Unlike the fin boxes, I didn't have a handy router jig and detailed instructions for the leash plug, so I just laid it on the deck and traced the edge of it and cut it out with an exacto knife. Seemed to be good enough, especially on a white board. Any tips on how to do this better are welcome.

With the leash plug hole cut, and the glass laid out, I folded the cloth up away from the tail, mixed a small batch of resin like I did for the fins, and epoxied the leash plug into place. Then I folded the glass back down and mixed up 27 ounces of resin/hardener to do the lamination for the deck. I figured with two layers on the deck, I'd need more resin, so I multiplied by 1.5 because, hey, that seemed about right. As it turned out, this was probably more than necessary. The lamination on the deck came out much thicker than on the bottom, and I didn't add a fill coat right away like I had on the bottom because there was already a lot of extra resin on the deck. Next time, I'll try and use a bit less resin on the deck, and I'll try harder to squeegee the extra resin out so that I get a nice thin lamination like I did on the bottom, then I can come back a little later with a fill coat over the top of it.

When the deck lamination had cured, it looked like this:

Applying the Sanding Coat

After giving everything another couple days to harden, it was ready to apply the sanding coat. I say "sanding coat" where some might say "gloss coat", but the board isn't being glossed, it will just be given a sanded finish. This is the third resin coat on the bottom, but only the second on the deck because of how thick the lamination went on.

Before applying this coat, I sanded everything down pretty damn close to being totally smooth. This last coat is going to go on fairly thin, so it can't fill any holes or gaps that are very deep. After this prep sanding, the board was looking almost finished already.

But if you looked close, you could see there were still some unfinished spots.

I masked off the bottom of the board and poured 9 ounces of epoxy over the top. It came out with annoying little bubbles in it.

I think this is because I accidentally added too much Additive F surfacing agent in this batch of epoxy. Regardless, the bubbles were small and I figured they'd sand out fine. When the epoxy gelled, I pulled off the tape, and as soon as it was dry enough to handle, I flipped it and repeated this for the bottom, except on the bottom I used the correct amount of Additive F. The bottom came out nicer.

At this point, the board is almost done. I just need to let it harden overnight and do the final sanding.

Final Sanding

I sanded the board with the electric sander to 120 grit, and stopped as soon as I got the board smooth to the point where there were no low spots with shiny, unsanded resin showing through. I didn't even touch the rails with th electric sander, doing them entirely by hand instead. I then wet sanded with 180, 220, and then 320 grit sandpaper (all by hand), and went over the top with a light coat of polishing compound just because it makes water sheet off the board better than a 320 grit sanded finish.

Finished!

Here are some final pics:

And posed with the two other 5'10" boards I used as design influences:

That's it, the board's done. I'll come back and add a ride report as soon as we get some waves around here and I can try it out. Thanks for reading.