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Hydrofoil board build #2

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by tweegster » Sun May 24, 2020 10:20 am

Pocketfoil #2

Construction Top to bottom:
-6oz carbon twill weave
-9oz carbon warp
-9oz carbon warp full length center strip
-9oz carbon foil mount reinforcement patch
-2 sheets 3/8 H80 Divinnycell glued together with gorilla glue.
-bottom carbon schedule reverse of top.
- Minwax Polyacrylic to seal the board

Basic steps:
- set rocker while bonding two sheets with gorilla glue.
- shape (42”x18.25”x7/8” in my case)
- Drill mount holes for straps and foil
- bond inserts and fill mount holes with epoxy/chop fiber/microballoon mix
- layup top and Vaccum bag
- light sand edges
- layup bottom and vac bag.
- gloss coat straight epoxy and epoxy / micro ballons/ white pigment on rails (heat and better filler/hider, my vac rails were not perfect)
-sand, careful not to hit fibers
- drill out the mount holes
- minwax, 3 coats
- cut amazon deck padding to desired shape
- ride and smile

Weight: 1.75 kg bare, 1.9 Kg after gloss, minwax and deck pads.

First ride (very light wind)
Light and playful, incredibly stiff equals very direct inputs to foil. Size is still easy to get going in “no relaunch possible for single strut kite” light wind.
Have not tried with straps yet, but they appear to be in the right spot (phew).

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by tweegster » Sun May 24, 2020 10:25 am

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by SE2 » Sun May 24, 2020 10:35 am

Beautiful product and very comprehensive description of the process. Thanks for the info and inspiration.
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by adam2 » Sun May 24, 2020 11:01 am

That is great, nice work!!!
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by Michael » Sun May 24, 2020 11:10 am

Thanks Tweegster, that's really nice, good job!
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by imdmitry » Fri Jun 26, 2020 3:10 pm

Your boards looks great. Similar boards from KS cost 800 USD. ... cho-42-red

You didn't use the inserts, did you? I see on a pix the screws are on top.
May be I should try to build. Looks like lots of work.
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by tweegster » Sat Jun 27, 2020 9:39 pm

This style of build was much less work than the stringered pu and eps build. No bottom shaping, foil track boxes or concave deck saved hours (OK days). Could do this construction over a weekend if you plan your layups.

I used stainless t nuts bonded in from the top. That way I can change em or drill out from backside, if I have to. Foil attaches with screws from the bottom. I take my foil apart everytime, so I did not want to mess with nuts and bolts. My marine grade t nuts and screws are stuck in blaine, so this is CDN tire stainless hardware, which is rusting a bit.

Good eye, I used the KS, ketos and groove as inspiration. I saw my first KS in person at the terminal just recently, is similar for sure, mine is thinner, has more rocker and I thought lighter.
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by imdmitry » Sun Jun 28, 2020 8:17 am

Thanks for extra info.
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by JonathanP » Tue Jun 30, 2020 8:26 am

Great build! Where did you get the Divinnycell? Somewhere locally or shipped?
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by tweegster » Tue Jun 30, 2020 8:55 am

Bought a sheet of H80 from Fiberglass supply in Burlington, so that is a bit of an issue now. I picked it up just before things went sideways. Pick it up or get them to cut it up into strips for much cheaper shipping.

If building pocket foils, a sheet is enough for 2.5 boards and extra to do a mast and some wings or repairs. The core cost is why I did not go with this construction the first time.
The time saving and end result is worth the cost IMO.

Today, I would compare Composites Canada and call and see what Swell Composites in Richmond can do. They bulk ship their supplies out of the states and have accounts with other major vendors. I priced out some stuff and it ended up cheaper in some cases. The resin they carry worked well.
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