First Compsand

General Discussion
1

I’ve been wanting to build a compsand board for ages, but life kind of got in the way. Finally I got around to it.

Dimensions are 7’2" x 21" x 2 3/4", nose rocker 5", tail rocker 2 1/2". 3/4" balsa rails, bamboo skins. Light deck concave, flat bottom. Dave Blakes Surftrux fin system.

Cell phone pics…

I’ve had it out in some small mushy waves only, but it’s easy to catch waves, nice and loose, fast in a straight line without that thruster drag that I’m not too fond of. Easy to paddle and effortless to duckdive compared to my fish. Pretty stoked about it. Unfortunately it will be a while till I get to test it in some good waves, but I’m looking very much forward to it.

Mistakes/lessons learned:

I glued up the rails with expanding polyurethane glue indoors, clamping the rails to the blank with brown packaging tape. That went well except for all the spills of sticky glue on the floor, had to scrub the floor with acetone or my wife would have killed me. Secondly my baby daughter woke up while I was in the middle of this mess, after I had put on the glue but well before I was done with clamping with the packaging tape. My wife was at work, so I was a bit stressed out while lulling my daughter back to sleep. Worked out OK in the end, but not something I’d recommend… Lastly I put one piece of low density balsa on top of a high density balsa joint. The lighter balsa snapped right there and I had to do a fix afterwards. Not too bad though. Next time I’ll use the bag to attach the rails.

I lammed the outer glass in the bag when bagging on the skins. This resulted in a lot of pin air, worst on the deck where it was covered with peel ply. It seems like you would have to wetout the glass with enough resin to completely wetout the peelply too. What a waste! While I would very much like to find a way to glass with a bag as my glassing sucks, I won’t do it like that anymore.

After one passed with the planer when shaping the rails I turned around and saw that I had cut deep into the deck skin and hit the EPS foam. Right there I almost abandoned it. But I cut a strip of bamboo and glued it in place then blended it first with the sander, then by hand. That actually worked out very well, you have to look for it to see it. I will for sure be more careful next time around.

The resin I used (Ebalta epoxy 110/GL) is too thick to be practical for the low working tempratures I was working at. Temperature in the garage was down to 5 degrees Celsius at times. Preheating the resin and board/blank helped, but it cooled down so quickly it was still a problem. Wetting out the glass was a big problem. I used a ‘heat tent’ to cure the epoxy at a reasonable temperature. Worst was the hotcoat. I think I would have needed half a liter on each side of the board to make it flow out nicely. Secondly it took ages to cure, I didn’t try the heat tent as I was worried it might collapse on the hotcoat. Anyway, the long cure time resulted in drippings and sags, etc. Which led to a long, long sanding job. I really need to find a way to heat my garage the next time.

I varnished with two component polyurethane and decided to try and polish it. That really made all the little blemishes stand out.

The board is on the heavy side at just over 4 kg(~9lbs). I don’t think it matters much though, but I think it’s a result of 1.5lbs core vs. 1lbs, a little thicker wood on rails than some use, 4oz over 2 under on bottom, 4oz under 2x4oz over on deck, the bamboo skin being a little heavier than balsa skins (but it’s really though stuff!), over-sized fin reinforcements (board is tail heavy even without the fins), slightly over-sized holes freehand routed for the fin plugs, etc.

Gotta say thanks to Bert Burger of course for showing how it’s done, Greg Tate for sending me the bamboo, Dave Blake for making the Surftrux fin system, and all those other guys I’ve PM asking for advice, you know who you are. Thanks!

regards,

Håvard

2

That looks nice for a first compsand build, and it sounds like you learned a lot.

That PU glue can be messy stuff, I got some on my hands once (don’t ask) and it took

a week to wear off. No solvent would touch it once cured. At least you didn’t get any on

your daughter, I don’t think the wife would care for that.

3

was the bamboo you worked with wide enough to go rail to rail (and long enough to go nose to tail)?

or did you have to butt joint the bamboo to make a panel large enough?

how many layers of bamboo?

4

Stocked!

My your immediate future be blessed with offshore winds and groundswell.

Drop me a PM/email about how the new finbox positioners worked out.

5

Hi,

the bamboo veneer was both wide and long enough for the entire board, I believe it was 8’x2’, 0.6mm thick, single layer… Very nice stuff to work with. Vacuum bagging the skins on was one of the things I was worried about, but that was actually one of the things that went smooth.

regards,

Håvard

6

Great first effort. It looks like a really fun shape. I love the baby photo on the bottom. One of the great things about making your own boards is the personal touches you can add.

Please give us more ride reports. I’m especially curious about the surf trux.

7

WHAT??? You dog! All you could do is downplay your work, leading me to believe it was a bust!

That board looks great. I had just about all the problems you had, except the baby girl. Took me twice to get the rails right, and I also managed to buzz right through the deck when turning down the rails. Patched it like you did. And I cut through the deck when installing the fin boxes. I’m so glad you persevered. All worth it.

Nice job. Glad for you.

OK. Let’s talk. I think working with full sheets of bamboo is way better than assembling sheets of soft balsa. Tell me how you would bag the rails on. The one on the bench now will have three layers of 1/4 inch balsa, with a bunch of cross cuts to allow the timber to bend. But, I wonder if I wet it with epoxy and then bagged it, would it bend enough without snapping?

Also, I’m sure you used too much glass. I think you need not more than 4 oz on the outer deck, but I use 1 oz under just to make sure I get a uniform layer of epoxy. And a couple of patches here and there, but not sure if that is even needed. On the bottom I use 3 oz, again with a 1 oz layer under. I used some carbon fiber patches under the skin where the fin boxes are, but I won’t do that again. The bamboo is just plenty tough. I’m not willing to jump up and down on them, but I am pretty sure they are stronger than balsa. Which might not be an entirely good thing if flex is your thing.

Anyway, it is great to see it finished and looking so good.

8

>GregTate>But, I wonder if I wet it with epoxy and then bagged it, would it bend enough without snapping?

Yes

With 1 oz under, why use any? Bamboo does not need a sandwich. I put my 'boo skins on with PU glue. Glass under is totally unnecessary. I’d put them on with Super77 if I thought they’d stay stuck until I glassed the outside. :wink:

9

Greg,

I think that vacuum bagging on the rails will give you a very even pressure, so I would actually think that the chance of snapping the balsa is less. I’m gonna give it a shot, pulling the vacuum slowly so I can adjust the positioning etc. The bamboo is very easy to work with and made the process much easier for a first timer. Thanks again. As for strength/weight, I’d rather build it too strong and a little heavy. Plenty of rocks around here.

Benny,

I think a thin layer of glass makes sense for two reasons, to make for an even spread of glue and to reinforce the bamboo in the fill (rail to rail) direction where it is weakest. But yeah, one layer on the outside might be plenty.

Jeff,

It’s a very personal board, I’ll tell you that much…

regards,

Håvard