Forming the rocker in paulow

[MFR]

Hi everyone

I'm in the process of building my first wakeboard. The board is shaped and ready for laying up on my rocker table. I am putting a 65mm continuous rocker, however the paulownia board feels fairly strong and I'm worried it won't flex that much under vacuum.

The board is 12mm thick in the centre with tip and tails fairing to 5mm over 10". The board is 1400mm in length and 430mm wide.

Does anyone have any advice on forming the rocker in paulownia or should it form under vacuum?

Kind regards
Matt

[BWD]

Might want tips a mm or so thinner, but it should bend to the table under vacuum, especially if it's a good vacuum. The longer you keep it under vacuum (or otherwise clamped weighted etc) while laminate cures the better the rocker will hold. Like all day, and then some. A mm of creep in the laminate can lose you 20-30mm of rocker depending on shape.

[Bigdog]

Where do you get the paulo? I'm in Canada and lightest local wood is cedar and its kinda heavy

[MFR]

Thanks BWD

Bigdog - I used junk supply.com.

I'll be uploading some photos of the build this week

[BWD]

You're quite welcome.
It should work fine, but a dry run with the vacuum never hurts to see how it will sit down on the table etc. Best luck and post up the results

[zob]

dry run

My vote.

It comes down to how god is your vacum setup.

[downunder]

MFR,

I think you will get a huge springback with 12mm deck. Think >60%. That means the rocker table needs >12cm.

Having said that it all depends on your top glassing. I do not glass it much, like 200g FG Uni. If you slap carbon, UD, triax, biax, or whatever, for sure you'll get different results with a springback.

This is 8.5cm table rocker with 3.5cm board rocker as a result:
viewtopic.php?f=107&t=2390040


Good luck.

D.

[MFR]

BWD - I will do a dry test with my vacuum set up and post up the results.

downunder - Thank you for the warning I will look into that before I lay it up. My intention was to use a triaxle glass on both top and bottom. How can I work out the spring back on this?

[tkettlepoint]

hard to work out the spring back ... comes down to trial and error. even foam and corecell will spring back some . then it comes down to a lot of factors of your wood. thickness, moisture content , etc



terrie
www.jellyfishboards.com

[rynhardt]

If you don't want to deal with the spring back, could you not make the core more bendy?
Maybe cut some horizontal grooves to allow the core to flex? Like they do when forming curved wooden furniture.

Sure it'll be a bit heavier, since the resin will fill up the space.