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Hello everyone. Yesterday I finished the rocker table. I'd like to create my first board, but I have a few concerns. First is about the rocker and concave. Board size is 140X45cm. I was planning 7mm concave and 2.7 cm of rocker at the tips (Is that enough). Should I go with a continuous rocker or center to leave flat? I would chose this second option, but I do not know how much of flat surface to leave, and where to start to bend the rocker?The other thing is the core thickness, 6mm thick plywood laminated with glass and epoxy, with carbon reinforcement. Is this too thin???

(P.S. Sorry for bad english)

I would stick with the continuous rocker for sure. 2.7cm is a good value for a lightwind board. You may want to increase that a bit but depending on your conditions 2.7 will be fine. Make sure your core does not spring back flatter from that though or it will be too flat for sure.

Stan

If put the concave in just the center and none in the tips you get a bit of flat in the center and the continuous rocker at the rail. Best of both worlds.

gbleck wrote:If put the concave in just the center and none in the tips you get a bit of flat in the center and the continuous rocker at the rail. Best of both worlds.

Concave is a bitch. If you do it wrong, it will create vacuum and the board will be pulled off your feet when jumping.

zob wrote:

gbleck wrote:If put the concave in just the center and none in the tips you get a bit of flat in the center and the continuous rocker at the rail. Best of both worlds.

Concave is a bitch. If you do it wrong, it will create vacuum and the board will be pulled off your feet when jumping.

Thank you for your replies. For what I need to be careful to do a right concave? And is it enough core thickness 6mm?

Sorry, I don't know about core thicknesses on wood core boards. But, I've never heard of this theory with concave and vacuum pulling your board off. I can't even imagine how that would happen, the board is cutting through the water, it is not acting like a flat suction cup.

Peter

foam-n-fibre wrote:But, I've never heard of this theory with concave and vacuum pulling your board off. I can't even imagine how that would happen, the board is cutting through the water, it is not acting like a flat suction cup.

With my initial rocker table design, I got out a board with pretty flat rocker in the middle, with bigger progression in the last quarter of the board. That's probably because of the concave shape. It was very wide in the center and finished around the place where the tip rocker started to progress. Depth was 4 mm. There was little transition from flat bottom to concave. When the board was lying down it seated flat on the concave edge.
So if the board was lying on the flat water it took a lot of force to lift her by the handle, so it was acting like a suction cup. This also showed when jumping, specially in low wind, when you pop less and the board lies flatter on the water surface.

Mike I like people who make there own boards so here is my advice: make the board flat it will be the simplest way then one inch rocker with continious curve and twin tips need very little volume and if the board is total wood then glass will not be needed just seal the board with a thin coat of epoxy sand and finish with a good coat of epoxy. I build these exact boards in California and that is how I do it. I also build surf boards and race boards with them I use foam for the core. hope this helps.

If you dont want to jump you could really build a wooden board ~20 mm thickness. It will definitely soak up water and the initial weight will increase from 3kg to 5kg...
There is a trick. Try to make a bottom from 4mm plywood and 15mm wood strips on top. Glue it on 5 cm continuous rocker table without concave. After a one season in the water you will have 10mm concave.
It would be soft and confortable board for freeride.
I would not recommend to use plywood as core material. It is heavy.
You will not be able to form a concave. Try to form rocker and concave from a sheet of paper and you will see.
Use wood strips or foam instead.

Thank you all for your replies. But now when I have rocker table and vacuum pump, I must do a little experimenting with concave and rocker. I decided to make a big light wind board 165X50, something like Spleene monster door. Does the Spleene door have rocker and concave???