Who needs a dependent variable?

This idea had started before Allan Gibbon’s Off the Grid thread, but it’s very much in the same vein (although not quite that far out there). A friend of mine wanted me to shape him a board he could just put in the trunk of his car after he finished surfing. The trunk space is 5ft max, so he designed a 5ft board. There’s an old thread out there where I asked for some design help with it, but we’ve finally got it designed the way we want it. Because this is purely an experiment and we have no clue if it will even work, we’re scrimping and saving everywhere we can. Scrap glass, minimal resin, EPS foam from a block, leftover basswood stringer, and… fins!

I think the only thing that will be proven to work on this board is the FU fin box. But that’s half the fun! I thought I would post some pictures of the project so far. All that’s finished at the moment are the side runners for the fins. I plan on foiling the center fin tomorrow. A big thanks to Chip for making it seem possible!

First step was to cut out the fins from the leftover basswood stringer. They’re 1/4" thick and the template is a copy from True Ames’ bonzer runners. These are the front fins.

Foil. I tried to do it all by hand at first because I was a little afraid of using my sander. That didn’t last long. Medium Flexpads are sweet! My foil is not, but that’s okay.

Glassed with 2 layers of 6 oz, scrap of course, and fin roving on the leading edges. I glassed them on a 1/8" sheet of lexan with a piece of wax paper on top. I studied Bert’s wood fin glassing thread.

Sanded. Took a while before I got the technique down.

Now for the center fin. Made with scrap glass (I’ve only glassed 12 boards and I have bags and bags of the stuff all over the shop!). 36 layers of 6 oz, which I read somewhere would get me the right thickness. These are actually too thick (3/8") and will need to be sanded down. Next time I’ll use 30 layers. Or squeegee out more resin. I used UV cure poly resin for these, mostly to get rid of the rest of the gallon. I want to say I used about 24 oz. I didn’t really measure, but didn’t top off the three 9oz cocktail cups I was using either. Used plenty of MEKP because the resin was opaque and it was around 50 degrees outside. With UV cure I was able to add a new color layer about every 25 minutes instead of hotcoating between colors. Plus I have no poly sanding resin. So when I finished the last layer of light blue, I laid down a sheet of wax paper to seal out the air. The colors are split up into sections of 6 layers, with the middle dark blue having 12 layers of glass.

After the first two colors.

Quick snap shot while adding the last section of light blue.

One big ugly slab.

Cutting out the fin. Template from True Ames, 6". Took me 4 hardware stores to find the right blade for my jigsaw. Ruined a different blade in the process though. I didn’t have a great way to clamp it down so I threw a scrap sheet of plywood onto some saw horses, clamped that down, then sprayed Super 77 onto the plywood and the back of the fin panel. Worked perfectly. I used a clamp too just as a safety precaution. Later I’ll post the picture of myself in all my “safety” gear. Mismatched gloves, hoodie, glassing mask… and an old scuba mask to keep myself from losing an eye to an errant piece of glass. Quite the sight to behold.

Rachel, this rocks.

I’ve been mind-shaping my own cut-down: my normal 10’0 noserider with 2 feet hacked off so it can fit diagonally in the back of my truck/shell. That way, I can keep it off the roof for stealth and also close the window in the rain. I know I’m cutting 24" off the board after shaping / before glassing… just don’t know which 24 inches!

Can’t wait to see what you came up with. Most of your boards are in the 6’2-6’8 range, right?

Starting with fins is killer. Nothing like a step-by-step thread. Keep updating :slight_smile:


Hello Rachel


I stopped reading the thread about the 5 foot board because of all the computer design debate. If you choose to design with a computer that’s fine with me. Sooner or later the design has to be made full size. That’s where I come in. I design in full size in my workshop. I work with engineers daily in my real job. Some times things just don’t work in the real world. I believe that your idea will work. I like where it’s going. Be real. Learn from your mistakes. Don’t get too caught up in what “should work”. Share the stoke!!! Great thread.


Nice work Rachael, I’m looking forward to seeing the finished product. It should be tons of fun, both in the making and the surfing.

A recycled surfboard?

Super job there Rachel! I really like the clean look of the wood fins with fin rope. Making boxed fins and glass on side runners is on my list of things too do for a few upcoming projects. Keeps the pictures of you progress coming. Good stuff as always…


Great thread! I like your project and look forward to seeing it’s progress.

Benny, I’m still mind-shaping the whole thing. I won’t be getting foam for it until after the 7th, so I have time to figure out just how I’m going to make it work. There are so many different compound curves and concaves that it’s mind boggling just trying to imagine it. I read somewhere that “great shapers” can see the board within the blank. I’m having a hard time just trying to see the blank.

Stingray, I don’t usually design on a computer, but when I was trying to get help that was the only way I could think to accurately show people what I was working on. Plus it helped me visualize the rails. I’m glad you think this will work, every vote of confidence helps!

Well I finally foiled the fin. Let me just start by saying that I will never ever complain about the price of a longboard fin ever again. There is some serious time and skill involved. I think I spent around 3 hours on this one and it looks horrible. But if I try to touch it up anymore I’m going to scream. Getting two perfectly matching sides is just slightly frustrating.

These pictures make it look a little nicer than it actually is in person. I have yet to hotcoat them but that will probably happen tomorrow.

I haven’t drilled the two holes yet either. I’m afraid I’m going to accidentally snap off the tab. Of course if I do then this will become a glass-on.

That looks good!

And as far as screaming goes, you did, after all pick just about the hardest (least forgiving) type of lay-up (Its not like a clear layup that you could fudge a bit).

Rachel, nice nice nice. Can’t wait to see the whole thing. I think the fin will be fine. It will not be rejected for lack of eye appeal.

Where did you get the info for the bonzer set up?

And don’t tell my wife we are talking.

Well I was hoping a 3 layer layup would make it easier to see the foil for me. But unfortunately it also allows everyone else to see. Next time I’ll go one color. If I can work up a desire to do another.


I’m glad it won’t be rejected. If my friend even says one word I’m going to remind him that it’s free and he can just shut his mouth.

I got most of my info from the Bonzer Q + A thread.

What Loxbox said is pretty much what I’ll be following, but scaled down a bit since the board is only 5ft. My measurements are downstairs but from what I remember the back of the box will be set at 4" up from the tail, with the back runners up around 11" and the front runners up around 16". I think the distance from the rail for the runners depends a lot on the tail shape and the shape of the concaves. As far as I can tell the back runners should be right on the edge of the main double concave.

Rachel, don’t be afraid of drilling the holes. But also don’t make a couple common mistakes and mess up your fin at the last moment.

On the vertical hole for the screw/plate, clamp pieces of really hard wood on both sides of the tab. Clamp them down very strong. This will (1) make a wider base so your fin sits upright and the hole goes in straight; and (2) Most Importantly will make sure the drill bit won’t separate the layers of fiberglass and split your fin at the tab. With good clamping pressure, the bit will remove material; without pressure from the margins, the path of least resistance is cracking open your new tab.

For the small hole for the roll pin, don’t be tempted to make a tight fit. On this one, the pitfall isn’t the drilling, but the tapping in of the pin. Make it a comfortable fit and then install the pin with a drip or 2 of resin (or 5-minute epoxy from the hardware store). Once installed, there’s not really any side-side pressure on that pin, so no reason to make it a tight fit. It does its job just fine with a smooth install and a drop of glue.

Fin looks great, so far. Can’t wait to see the board. :slight_smile:

Nice fin Rachel. The boys from my street are all college age now. They have a 5’2" fish that they pass around and I’ve fixed it plenty of times so I know it works. The fish is about four years old now. I know you have the skills to design and build a 5 foot board. Today I took a 6’11" template and compressed it down to a 6’1" egg. Got a weird kink where I blended the template. My friend helped me make a curve with a piece of wood molding that would flex to the curve that we needed. Fun stuff. Great thread!


Nice project Rachel, Keep the pictures coming. On the horizontal hole and pin, I’ve used a sawed off stainless ?3/16"? bolt instead of the rusty roll pin, don’t know if stainless roll pins are avail. Drill some test holes in similar material to see how your bolt size will thread in, doesn’t need to be too tight.

Fin looks good. I remember my first fin (much greater than 3 hours for the whole deal) and at the time I thought it was taking entirely too long! Hah! It is time well spent.

You are brave for doing the color layup on a first shot.

Well after a short little trip up to RI for traffic court and several dozen errands, I’m back to work on the board. Before I left I cut out two rocker templates and a outline template from a leftover sheet of masonite. It’s nice working on small boards because you get to get rid of all your too-small extras.

I ordered an 1’ x 2’ x 8’ block of 2lb EPS from an insulation company in MA. Only $76 and I can probably get 3 or 4 boards out of it, so it’s definitely worth it. But getting it home was interesting.

EPS is My Co-Pilot. If it was 2" shorter it would have fit in the car below the dash.

Now I just need to hotwire everything without electrocuting myself or burning the house down. I want to make some of the tools I’ve seen other people make on here so I can easily cut the outline and such. We’ll see how much time and how many guitars I can steal strings from.

And of course while I was in RI I got two more fun projects from the same friend who wants the 5ft board. I think he gets some kind of sick joy in asking me to do these things.

The easy one, based on the Yater Rudder on True Ames in super lightweight balsa.

The hard one. Any one have any idea how to glass this? I was thinking of glassing the vertical sides first, cutting slits where the side fins are, and then glassing the side fins, making sure to use enough rope to give it a nice fillet at the joint. I was also planning on using a lot more than 2 layers of glass because these are super lightweight and super fragile. I mean I’m afraid to hold them.

Wow, that will be an endeavour to glass…

Block of eps, cut out slots for the fin and wings so they "rest"in proper position, then vac the whole thing and peel of the eps when hard??

Ooh I wish I could do that. I don’t have a vac yet, but maybe when I finally do these will be easier.

Seeing what you have done in the past, you’ll have no problems making the hotwire bows to do your outline and rocker…I do outline with a router, I think it comes out much nicer with no hotwire crust…

For the fins, seal them with thinned epoxy (thin w/heat or denatured alcohol) or poly (thin w/styrene) before you glass them to avoid problems in the lam from the balsa either outgassing or sucking up too much resin after you have walked away…

If you can take apart the ‘t’ fin (dissolve the adhesive), do so, and glass the main fin and then treat the little ones as mini ‘glass-ons’ onto the main fin. If you can’t take it apart, I think your method will work OK…

If those fin bases are already the correct size for a fin box, trim them down and fill them back out with glass…I’d be most worried about the strength at the bottom of the fin where it meets the base, and the base that goes in the finbox…

That’s the way I’d approach it, but it may not be the best way…good luck and let us know how it turns out…