Plywood Foil Board

[daspi]

I have leftover cedar from my MAKO twintip build (I ripped it into strips and built the same way you'd build a kayak/canoe). I may rip the remaining board into flat 3/8 inch boards/wide strips and make my own "plywood". Just force some shape into it when I glue it all up to achieve rocker and maybe some minor concave.

Sounds interesting. I'd like to follow your build, keep us posted ether here or start a thread.

[Wbrussow]

Hello, for my foil board build, here is my plan:

1/2” XPS core
1/8” ply top and bottom
3/4” half round to cap the perimeter
1/2” x 6inch wide core between feet (also what the mast will bolt to)

I doubt I will need more than a 4oz glass layer on top and bottom, though I am open to suggestions. I am hoping someone can give me insight as to how much epoxy to buy. Not looking to have a bunch left over. The foil is an LP kite foil, 720cm^2 wing

Cheers!

[Breze]

Here is a laminate calculator https://www.r-g.de/en/laminatecalculator.html
Can not help you with yout initial question, as you don`t mention lenght and width.
Remeber the wood will drink a lot. Better some left over , than running out of epoxy.
Overthink ply on bottom, it will be heavy. Think instead of a leash for your LP

[Wbrussow]

Thanks Breze,
I am not familiar with a leash for Hydrofoils. Still so new to this that I have never tried foiling. Where would I attach the leash to Hydrofoil?

For board size, I am thinking about about 5ft x 22”

[Breze]

5ft x22" or 150x 55 is way too big. If you are kind of normal size go for 130x46
It seems that bonding Xps / wood works better with a PU glue. That was the result of a test a very good board builder did, he compared diff bondings. Epoxy works, but PU was way better.
The leash could be a simple 4mm dyneema line between your nice LP and the tail of your board eg the back strap. You wouldn`t be the first who ripped out his foil.
I built my sec board like this viewtopic.php?t=2400849. Now i enjoy a nice production board.
But i would recommend you to buy a used one or a cheap Gong , this : https://www.gong-galaxy.com/en/product/ ... ch-fsp-2x/

Edit, here you can see the leash foil to board https://oaseforum.de/attachment.php?att ... 1477247433

[Wbrussow]

Thank you for taking the time to answer, Breze. I appreciate it!

The LP has a lengthy mast, 100cm. Probable not the best for learning, but I got it for a great deal. 600 CAD. I was thinking of making the board longer to help with not catching my front edge while learning. I also have an older Liquid Force 5’3” fish, but suspect it is not nearly strong enough to directly mount the foil, otherwise I would just drill some holes and “send it”.

[daspi]

Actually the LF fish boards are strong enough. Just drill and off you go. I had one and it lasted well.

[BWD]

If you use 2.5mm birch ply you dont need any glass, but you should make the core at least 1”/25mm thick under the foil and stance area. This should be very strong and stiff. Also this ply is usually US $12-15 for a 150x150cm sheet, and used by cabinet makers all over northern hemisphere. I have built surface directionals this way and it is rock solid, if not that light....
I would include partial stringers under the foil mount and stance area though, especially the foil mount because of compression and point loading. Stringers could be ply strips or light wood -anything to handle compression better than foam.
6-12oz tape over the rails is good. Epoxy glues plywood to xps very well, fyi.
For dimensions, if you are over 75kg or foil in light wind, I would go for something like 48-50 cm x 120-140 according to your preference.
A little extra width/float does help waterstart and restart in touchdowns in light wind. Build a 110x40 mini board when you get to the pirouettes and strapless air jibes, my take.

[Mikey]

I´m having an eye on this one for my next home built:

https://www.3accorematerials.com/en/pro ... lsa-veneer

Normally I´m using bcore qx blanks from from bcomp but with 210 g/liter they are a bit heavy for board volumes above 5 liters or so. The Baltec VBC is 156 g/liter.

@BalsaMichel do you have pricing for this ? looks great (but expensive)?