Hey Boardbuilders,

I decided to build a FAKO-MAKO out of plywood. I have my rocker table all set but need a good way to bend the plywood. Not an easy task because it is a complex bend - tunnel concave but with a good amount of rocker.

I am hoping there is a good way to bend some plywood without having to go to super thin veneers and build my own plywood.

Any ideas would be appreciated.

Ed

steaming with an iron works.

fiberglass veneers works.

if you've already got a rocker table,
the easiest is laminating from thinner layers.

they dont need to be super thin.

3 plys of 3mm plywood will hold a nice shape,
even 2 layers of 6mm works
(glass accordingly for desired stiifness/strength)


-bill

Bill,

The concave shape really stiffens up the board, so I does not need to be very thick. I may add some fiberglass or carbon cloth to the high stress region between the pads.

Which type of plywood do you recommend? Any good sources around here? I am on Cape Cod - not far from RI.

Thanks,

Ed

hi ed,
luan is cheap , pretty , easy to get at home depot.
the veneers are thin, probabaly has voids in the core.
and yet any problems are easy to fix with a layer of 4oz glass.

ocume ( marine grade ply) is usually special ordred from lumber yards
but i know some yards in providence carry it.
sort of pricey ( $50 per sheet) but high quality, strong and pretty.
probably not needed for a kite board.

in between , you should be able to find birch plywood.
lots of folks like it, but i'm not sure why.

dont forget to cut your plys with the outer grain going length-wise.

for good strength / weight my favorite local stuff is cedar planks.
a single (solid) core can be very thin, but for lots of bending there's
too much waste if i tried to make plys w/o a bandsaw.

-have fun,
bill

I recently made first attempt at "fako" used 6mm pine 5ply with 3mm luan 3ply laminated on top using polyurethane glue.

My method of construction:
1. Cut out 6mm ply (final outline +20mm)
2. screwed this on to rocker table (screws within 10mm of outline)
3. Next cut 3mm ply(final outline +10mm)
4. applied glue to bottom layer
5. Screwed top 3mm layer on, working my way out from centre.
6. alowwed to sit on rocker table for couple of days while glue hardened
7. unscrewed from rocker table and cut out final outline with jigsaw (ie, cut off 20mm)

result

The ply has held concave very well, between 15 - 20mm down from 21mm on rocker table. Rocker has not held, and is only around 20mm, down from 70mm on rocker table. This was not entirely unexpected, as 3mm top is very flexy, but I dont think less bendy (ie thicker) ply would conform to bottom shape without some other teqnique. (Try bending a piece of paper with both rocker and concave to illustrate problem)



I have not completed project yet, intend to paint and trial board in next month or so. But as the rocker is not what I want, trial is more to test flex / outline characteristics in flatish water, not choppy / small surf where I normaly ride and more rocker is necesary. For fako marko II, am thinking of using two layers of 6mm, but making logitudanal cuts with router on underside of top layer to help top layer conform better.

any suggestions?

hi rodder,
i think you've shown that the amount of rocker and concave that you are looking for puts a lot of stress on your bond layer.

so my suggestion is to
reduce the stress by using more layers that are thinner (3x 3 mm)
and increase the strength of the bond by using a good laminating epoxy instead of the urethane.
(MAS, System3, West, etc)

full strength cure is probably more than 48hr with either flavor

no worries
-bill

Layer of 4oz glass on deck is usually enough to hold rocker.
But w/ epoxy you probably don't need glass.
For the board you made, if you want more rocker, you could
put it back on the table, sand off any deck paint, glass deck with epoxy and 4z, cover with polyethylene, pile weights on it to make it conform to rocker table. You can also get some thin wedges (for masonry) at hardware store and use them to kick the rocker up at the tips, to counteract springback. Do leave the board on the rocker table for a couple of days,,, shold be good.
With wood boards I glue the "core" layer to the bottom on the table first, and when it's cured I can see if I will want to add wedges under the tips to ensure enough rocker when I make the deck to core bond.

Bill,

I knew this was not going to be any easy board to get to come out right.

Any idea where to get some 3mm in the MA or RI area?

Thanks,

Ed

ed,
i sent you a pm with some thoughts.
but in the meantime, a friend made a recommendation for
boulter plywood in sommerville

http://www.boulterplywood.com/


lots to choose from.

Bill,

Thanks. It looks like they have what I need.

I will let you know how it works out. If all goes well and you want to make a woodie mako you can borrow my rocker table.

There is something special about the Mako.

Ed