Surfboard - 5'4 mini simmons

Sometime last year I got it in my head to try my hand at making a surfboard. I’d shaped and glassed one in college on the cheap, but never installed the fin plugs, so it barely counts. Re-reading about the process and watching videos and such, it seemed like a relatively modest task, that could be done in maybe 5-10 solid work blocks, if all goes well (it didn’t).

I’d long been intrigued by the mini simmons design, a weird shape inspired by experimental boards from the ’40s and ’50s that became trendy over the last decade. The shape takes “short and wide” to extremes - they’re supposed to be super fast and nimble, good for small and mushy surf. Somewhere I read that they look and ride like a wet bar of soap. Nice thing about shaping an alt board is that its eccentricities are part of the experience. For a performance shortboard, you want predictability and control, but something like this is just for fun.

To get started on the design, I looked at pictures of mini simmons and read about surfboard design until my eyes bled. There are lots of simmons-inspired designs out there with things like fish tails, quad or twinzer fin setups, narrower nose, and the like, but I decided to go pretty traditional, with a full round nose, twin keel, and very wide square tail (slighly rounded, actually). I went a bit thicker than is common and very much on the low side for rocker, wanting something that was exceptionally fast and floaty, while still being very very short. The board I designed is 5’4 x 22 x 3, and around 40L.

I found a site called Greenlight Surf Supply that had a kit including a custom EPS blank, glass, and epoxy, for just over $300, which seemed like a great way to start. Their how-to pages were also incredibly helpful in going through the process. I sent them a CAD file of the shape I wanted, and they cut out the template and the rocker to my specifications. I could’ve cut the template curves myself to a high degree of precision, but rocker and foil is a lot harder. The previous board I made, I cut the stringer to final shape before gluing it into the blank, which served as a reference for mowing the foam down to the proper dimensions - I’m not sure how to do it well with a traditional blank.

Here’s what they sent me - the blank is in half down the middle to save on shipping costs. Kinda neat how they pack in the glass and resin inside the negative space.

here are those two halves all glued up (with some resin pigment for contrast)

The mini simmons is something many serious surfers will roll their eyes at, so I decided to be as extra as possible and do a retro fabric inlay and resin pigment. I found this pattern of upholstry fabric that seemed perfect (though it is unfortunately very thick - thin cloth would’ve been better). Pictured also is the resin pigment that formed the base of the color, though I muted it with some white and black pigments.

A big barrier to doing this project was dealing with the foam and epoxy dust. Clearly I don’t have a dedicated shaper’s bay, but I rigged up some plastic sheeting to contain the worst of it - looks like a scene from Dexter.

Dust still got kinda everywhere, unfortunately. I later read the idea of using a pop-up greenhouse as an impromptu shaper’s bay, which I’ll probably do if/when I make another board.

It takes a practiced grace to be able to make nice curves, especially if you want them to be the curves you planned, (and symmetrical). Surfboards are nothing but a series of multidimensional curves. Luckily, people have come up with some pretty cool methods for getting even curves without needing to freehand much. To cut the dome of the deck, you make a series of “rail bands”, cutting flat surfaces with sharp angles between them, and then go back at the end and round everything out. Look it up if you’re unfamiliar. Here’s the first set of rail bands cut on my board.

This step involves removing a LOT of foam - I have a handheld power planer that I used for this purpose, hooked up to a shop vac to control dust. Pro shapers use modified planers for almost all of the shaping, I’m told, though it’s risky, as it removes a lot of material fast.

After cutting the rail bands, I did the bottom contours, as I wanted a somewhat geometric frame of reference. Here I went with a fairly modern single concave under the front foot, to double concave, to a vee in the tail. This seems to be standard on almost all small wave boards these days. I did put some belly in the nose to better manage the width and almost nonexistent rocker. I might’ve done a couple passes with the power planer, but most of this was cut with a surform and 40 grit sandpaper. Here’s a shot partway through the process.

Next up I smoothed out the curves with a sanding screen, and moved to a higher grit sandpaper to get everything nice and fair. Here’s a before and “during” comparison:

That step involved a lot of assessing the curves from every conceivable angle and lighting, with lots of touch-up to make it pleasing to the eye. Here’s the final product!

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The board uses EPS foam and epoxy resin, with two sheets of 6 ounce fiberglass on the deck, and one on the bottom. This is a very heavy glass schedule for a short board, and I figured it’d be fine stringerless (there’s just a glue line, no structural stringer), especially considering the thickness. Still, I initially planned on adding a carbon reinforcement in the lamination, shown in the picture below. I sprayed some Super 77 on it so it’d stay in place during the lamination, but that ended up dissolving the thin material holding the carbon in place, and I ended up srapping it.

Here’s a picture my wife took of me all prepped to pour the laminate coat on the underside.

After trimming the excess and flattening the laps, I cut the fabric inlay to size and spray-glued it in place on the deck, then glassed over it. Once that was all cleaned up, I brushed on a fill coat on either side. I love this picture, the pattern really pops.

For the vibe of board I was going for, I wanted to do glass-on fins, so naturally I made those as well. The fin template is something I pulled from this cool site blendingcurves.com, which is a collection of surfboard templates available for free. Traditional mini simmons use unfoiled “half moon” keel fins, but here I decided to go a bit more modern - not all the way to upright fins, but a full, wide base keel with just a hint of a cutaway. The core is made from an off cut of 5mm okoume plywood from my canoe project, foiled by hand with a flap disk in an angle grinder. The inside of the fins is flat, so there I laminated the same fabric I used on the deck of the board. In retrospect I should’ve painted the wood under the fabric white first, so it doesn’t dull the pattern once it’s wetted out with epoxy.

Marking the fin placement was very nerve wracking - simmons fins are placed almost all the way to the back of the board and close to the rails, sometimes with no toe or cant. I put a modest amount of toe-in (pointing the fins towards the nose), and four degrees of cant (leaning outward from vertical), which should help the board turn well and transition rail to rail, at the expense of some down-the-line speed, perhaps.

Here’s the jig I came up with for holding the fins at the right angle - I tacked them in place with a little bit of thickened epoxy, then came back later and reinforced them.

The fins were made with two sheets of 6oz glass per side, and I layered fiberglass roving around the base for support, then a strip of glass in the angle over the roving, then two more sheets of glass from the surface of the board covering the whole fin, so each fin has like eight sheets of fiberglass, plus more at the base.

I’m glad the board has glass-ins now, but this made the project so much harder. Getting the fiberglass faired in was really tough, and I actually burned through the lamination in one spot, so I had to patch the board, and of course the color would never match, so I had to do an opaque coat on top of it, and then I sanded through that in patches making things splotchy… It was a nightmare. Plus having two permanent fins in the way made it way harder to do the final sanding and polishing later.

Anyways, after repairing that and sanding it all smooth, I taped off and painted on pinlines to cover the edge between the colored laminate and the clear deck, and the edges of the fabric inlay. See the glamour shots below. Somewhere around then my daughter was born - rudely interrupting my progress, so it sat at this stage for a while, even though all that was left was the gloss coat and sanding and polishing.

I really like the bottom right photo there, the curves feel very retro futuristic to me.

When I did get back to it, I had another major setback. The gloss coat for the underside went fine, but on the deck I must’ve had some sort of contamination, and the epoxy wouldn’t self-level, beading up and leaving spots exposed. I also forgot to add the sanding additive that might’ve helped somewhat. It doesn’t show up that well in photos, but it was bad enough that I felt I had to sand down and fix it. Discouraged and busy with two kids, I let it sit like that for the better part of a year.

I was concerned about sanding through the fill coat in spots and into the fiberglass cloth, especially as I didn’t have proper sanding tools (palm sander is too slow, angle grinder is way too fast), and it was essentially inevitable that I’d sand through the pinlines. Seemed worthwhile to finally get a sander/polisher, as I’d wanted one on another project anyways. I found a good deal on a used one, and so picked that up, and made do with a homemade interface pad for now. Spray glue did a pretty good job holding sandpaper onto the pad, and it got the job done, but I’ll definitely pick up a proper one before my next big project.

An upcoming trip was the push I needed to finally wrap up this project, and I committed to finishing it beforehand. I did indeed sand through the pinlines in some places, and had to retape and reapply the paint, but wasn’t that big a deal. It was very hard to sand just the right amount, though the sander/polisher was the perfect tool for the job. The glass-on fins were still challenging to work around.

The second attempt at a gloss coat went much better - better even than the gloss coat on the underside, which I’d thought had gone well enough. Part of the issue I think was working time - the first gloss coats I’d done in my very warm garage, and the epoxy kicked pretty fast, so even when done well I had some undulations. Doing the final gloss coat indoors meant cooler temperatures and a much longer working time, so the surface self-leveled nicely. The downside was an unfortunate accident ruining my wife’s favorite dress.

After that was a lot more sanding and some light polishing. Again it was nerve wracking to sand enough without sanding too much. This was especially true of the underside, which had a less even gloss coat to start with. The better you do each step, the easier the next becomes. Really it was just the first grit that was the challenge - once that takes off all the shine you can move up, and from there you spend relatively little time at each grit. I sanded the rails (and on and around those damn fins) by hand with a scrap of foam, which wasn’t too bad actually. A properly formulated resin sands well enough once fully cured. I worked from I think 320 grit up to around 1500, then went over the board by hand with some auto polish that I had. The finish was very nice, certainly good enough for a board that’s going to be waxed up and used. For a showroom level gloss coat I’d probably polish in two stages and use a wool bonnet on my electric polisher.

The finish looks really nice in this picture:

And here are some shots of the finished board

I did finish it in time for that trip where I was able to get a fair bit of time on the board. It went great in soft, mushy stuff, though I was too scared to take it out in the dumpy, closeout shorebreak that made up several of my surf sessions. My brother was able to ride it a bit too, and his experiences were similar to mine.

It really does paddle a lot like a longboard, in that it sits high on the water and moves far with each stroke, but it doesn’t have nearly the momentum of a longboard, so there’s no glide when paddling. It caught everything though, and I found I could keep cruising on the swell well after the whitewater had faded. On waves with enough shoulder and power to do something, it rides just like I’d hoped. “Zippy” is the word for it. I didn’t get it carving on rail (not that I tried in earnest), but it takes off, pivots with a twitch, and skates all over the place. Super lively, and seems great for surfing soft open faces. I was worried it wouldn’t handle chop well, being so wide and with the corkiness of EPS, but it seemed fine, actually. Many times I found myself coasting in a cheater five stance after the wave died - it glides very nicely from a forward position, and it’s so short you don’t actually have to be that far forward to wrap your toes.