Kiteforum.com

Here's some info on a wood strip board I just finished: 137x43, 33cm tips, 4cm rocker, 3mm concave, 38mm rocker.

The goal is to be all-around board for 80kg rider in area where lulls come more often than gusts, with some tip area and width for both pop and glide, but not too flat a rocker line... ...hopefully the rocker, tapered tips and light glass will keep the width from causing too much of a beating when it blows up and gets choppier... Tips seem maybe too flexy, but the middle is fairly stiff... A few details....

Core 2 layers of ~7mmx20mm western red cedar strips
3mm thick at tips, ~14.5mm at center, ~6mm at rails
Rails and inserts are epoxy filled with cotton fibers and graphite
Rails rounded 50/50 between straps, harder at tips
Skin 6oz e glass plus 6 oz eglass reinforcements
Resin Research epoxy.
bare 3.2 kg

The weight has me wondering if I should have used lighter straps than the luxuries, which add more weight than I like - they are like 500g apiece but nice and soft...
The strips I started with weren't milled precisely, and I had no planer, so there's a bit more epoxy in the core than I wanted...
Easy to get shape right with 2 layer core, but a single layer would probably save 150-200g. Maybe next time, this one was partly just to use up the strips on hand....
Not ridden yet, we'll see.
building pics:
The start, outline routed from a template poured epoxy rail the bottom layer of the blank, next to old boards 135x40 and 145x42 Shaping the core layers before gluing up Gluing on rocker table Just wanted to post this board to say thanks to those who have given some advice along the way, it's the first one I have made for a while, I'll try to give an update on how it rides, when I get around to riding it....

Nice piece of (art)work

Thanks for the kind words. I just hope that it will be useful for riding as well as looking.
Also, it has plenty of small flaws, that the pictures don't show

Looks really good! Don't worry about small blemishes.....that tells you it's a one off and not a popout from ???

Stan

look really nice!

Hi!
How much spring back does this kind of construction have? How high is your rocker table setup, to get 4 cm rocker after spring back?
Is concave also formed on the table or do you shape it by hand, planing or sanding?

Table rocker over 137cm (between board tips) 5.7cm.
Core glued up on table without glassing.
Core came off table with 4.45cm rocker.
Final rocker after a few days of settling/curing ~4cm.
This is pretty standard for thin, gently curved wood laminations, losing ~25%.
Table has ~6mm concave formed by a batten under the middle 40 or 50cm.
The concave mostly disappeared from the core though, due to the properties of the wood strips, leaving only ~2mm.
To get more concave, I used a jig attached to the board handle screws and board rails to bend the middle of the board while I glassed the bottom.
Still, most of the concave bent into the board was lost, leaving only ~3mm.
Fortunately, this is about what I was shooting for.
The nice thing about wood is bending it creates good fair curves,
the concave flows into the flat ends of the board very smoothly.
It would be a pain to shape that with a sander or planer and get it so even.

Nice work!!

What did you use to glue the cedar strips together?

Thanks duarte,
I used the same RR epoxy for ev erything.
My wood strips weren't precisely milled, so I would have had weak glue lines with anything else.
If you use more precisely shaped strips you could use polyurethane glue and it would save weight and $.
Lacking both a planer and precise strips, I used epoxy to edge glue the strips and also to glue the top half of the core to the bottom, probably adding 5 or 6 ounces to the overall weight.
If you get strips that fit tightly enough for gorilla glue or similar, you can save some weight.
Likewise if you could run the blanks through a thickness planer.

Still going well, rides fast... Pop is good, but it's a little fat for me when fully powered.
Working on a skinnier version now...