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Screwed wood composite with 2 part rocker and 2 part concave

Posted: Fri May 04, 2012 7:22 pm
by bay surfer
Your basic Screwed wood fiberglass Composite board, with a 2 part rocker, flat in the middle up on the ends, with a 2 part concave 1cm in the middle less than a 1mm at the tip, DM 140 x 43 cm, Wt light as a LF Board. Good flex, due to the flat ends.

I can Torture thin plywood into shapes, by Screwing the a ply sandwich to the table (screws act like a press). Shapes that would be impossible with a vacuum table when using plywood..

Construction basic Snowboard like, Epoxy fiberglass sandwich between 5 wood plays (3 plys on bottom) and (2 plys on top) , fiber glass stringer in a X pattern to tips and rail stringers , layup screwed to rocker table, holes are filled after curing with epoxy and flour.

Fun all-a-round upwind rocket.

Re: Screwed wood composite with 2 part rocker and 2 part con

Posted: Wed May 09, 2012 1:07 pm
by jaros
Hallo,
Nice board!
The same thing is also possible with vacuum bag. I made a few Mako boards that have 2cm concave and huge rocker line form plywood.
You can not beleive how far can you deform thin layers of ply and glue them togather to stay in shape.
Greetings,
Jaros

Re: Screwed wood composite with 2 part rocker and 2 part con

Posted: Thu May 10, 2012 5:32 pm
by bay surfer
Thanks for the complement.

Nice thing about screws you can pinpoint pressure if needed, But your limited to a sandwich, for the two part concave I had to eliminate the sandwich in the middle at the ends and putting alot of pressure on the outside plys at the ends, loss of material and epoxy less wt, which is nice. Also to reduce wt and increase flex I eliminated one of the plys on the topsheet. I'll have to see if I can break the board over the season, with all the Ply sandwich boards I've made never have been able to break one.

Re: Screwed wood composite with 2 part rocker and 2 part con

Posted: Thu May 10, 2012 9:30 pm
by tmcfarla
Awesome board. How thin does the plywood need to be to get it to hold its shape when epoxied together? How close are the screws spaced on the table?

Re: Screwed wood composite with 2 part rocker and 2 part con

Posted: Fri May 11, 2012 12:27 am
by bay surfer
Screws are placed every 10cm or so along the middle and outside edge and where needed, with a build with concave excess epoxy is squeezed out from the middle to the outside edge due to the pressure from bending the ply so screws only needed for inside and outside. Note outside holes are cut off of board only the middle ones are filled. 150ml/5oz epoxy and glass tape used when building this board, 7 layers of fastdry poly and some paint for fun.
I like 1/4in, 7mm AC ply since the glue is Waterproof and 3 ply, on this board I planed off a ply on the top piece for more flex. last year I used some luan on the top for more flex\lightness, but the luan delaminated because the glue was watersoluble, water migrated from a pinhole on the edge, so good ply is a must.

Re: Screwed wood composite with 2 part rocker and 2 part con

Posted: Fri May 11, 2012 4:23 pm
by nafets
Can you please post a picture of the building board?