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Topics - JohnnyTsunami

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The Shape Shack / Foaming Epoxy Additive - supplier?
« on: September 18, 2022, 12:09:26 AM »
I can't seem to find the mention of it, but does anyone have experience with foaming additives for epoxy? The Carbon Art mentions it when they glue the divinycell https://youtu.be/KqLLLoNWoCo?t=121

All I could find was this stuff from europe. https://shop.hp-textiles.com/shop/en/Liquid-foaming-agent-HP-BEL11.html
They recommend 0.5 - 4 % added.

Does anyone know of a US supplier of something similar and how to mix/use it?

I would use this for gluing the sandwich of D-cell down. I made one board with D-cell and it's bullet proof but was very tricky to do the rails, which had some voids in the nose and needed to be partially cut out and filled with epoxy later.

A foaming epoxy additive could be used in the bends and avoid this issue. I could also use it for boxes, etc. and avoid gorilla glue altogether I would imagine.

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Classifieds / 2022 Fanatic Sky Wing 95L 54
« on: May 04, 2022, 09:07:41 AM »
2022 Fanatic Sky Wing 54 95L in great condition.

Located in Monterey. I can meet in the SF Bay Area on weekends.

It has 455 miles on it, in great shape. No issues regarding durability or longevity. The only minor issues are pictures and that is paint chipping on the rail. This is due to how it sits in my truck and rubs a Tupperware box.

Im 77kg and this is a good board for me, just big enough to slog in almost no wind but small enough to rip turns and jump.

If you have plenty of energy and can go to flat water spots with plenty of wind this would be possible to learn on. Then you can keep it around when you downsize to a sinker.

There are some reports of some batches of these boards being heavy, this one weighs 6.62kgs/14.59lbs as pictured which would make it a light one!

https://www.mackiteboarding.com/2022-fanatic-sky-wing-foilboard/

https://www.fanatic.com/foil/boards/wing-specific/sky-wing

Im in Monterey but come to Watsonville for work and often to SC or north on weekends.

Price is firm, youll be paying 1,600 plus tax = 1,750 for this board in a shop - if you can even find it.


3
The Shape Shack / Wing Board Build 4'6" x 23" x 5.25" ~75-80L
« on: March 23, 2022, 11:04:38 PM »
Ahoy!

I started my wing board build and it's been a trip already. I had to find some foam, build a hotwire, build a vacuum pump, get all the gear, etc. Anyway I started tonight and I'll share what I learn along the way. See this thread about me asking for glassing schedules. https://www.standupzone.com/forum/index.php/topic,37839.0.html

I was up racing in SF a couple weeks ago on wing and was able to check out all the boards the fast folks were riding - almost all of which are DIY jobs. I was actually able to talk briefly with someone who helped shape some of them and makes other beautiful boards. My glassing schedule will be similar to his, maybe a little lighter.

The build will consist of:
   - .9lb EPS foam (.9003 lb/cuft to be exact, measured by weighing a uniform block).
   - Carbon/innegra hybrid 4oz
   - 4oz s-glass to put on top
   - 1/8" 5lb divinycell only the standing area (S-glass underneath, or maybe the carbon/innegra).
   - 5lb thicker divinycell to beef up the boxes and to make 1" wide boxes for the strap mounts/leash.
   - 16" Chinook dual tracks
   - Tuttle from fiberglass supply
   - Vacuum bagging everything

I hotwired out the blank today using a DIY hotwire. I can share the materials but basically it's just a buck-booster from amazon for 16$ and a laptop 12v 5A charger running at 10V 4.x Amps and a wire.

https://www.youtube.com/watch?v=jgIcN2TPt9Q

Then I used a harbor freight hotknife for the outline. It looks bad but I ditched the flimsy adjustable guide and made my own perfectly square guide that's 5.125" deep (slightly not deep enough).

https://www.youtube.com/watch?v=zJSe0OtH6EE

The blank, just hotwired, weighs 2.7lbs. This is more than I was planning, but that's the lightest foam you can get. Calculating off the weight of a block of the same foam to get the exact density and using the weight of the hotwired blank, I get 85L as the volume now. I expect to lose about 10L, which would make it close to my weight in KG.

Originally I was planning a 60L board, but I'm thinking now if I can use this in lower winds, I can sell my larger 2022 board and save some $ for other gear.

The hotknife was interesting, a bit too hot and when I didn't hod it down right it made a couple gouges. It would be safer to make a top and bottom template. The hotwire worked well, although a bit slow. If you make some waves in the foam you can't really go back over them if they are under 1/4" or so since the foam sort of turns to goo and doesn't cut cleanly anymore, but I will sort that out with sand paper. I should have been more careful on the nose as it has a sharp turn and one end of the wire went over before the other, causing a potential issue. We'll see tomorrow when I go to do the rail shaping.

I plan on using a tuttle to use some fast foils. However, I have to wait 2+ months for my foil and the ones I do have are a tuttle that goes 4" behind a normal tuttle, or they are a dual track system (axis). So, reluctantly, I'm putting in 16" chinook dual tracks (.8lbs for just the tracks- same weight as the 10") to future-proof the board. The tracks don't fit with the tuttle in between by about .5", so I plan to cut the dual track flange back a bit to nest with the tuttle. I'll do divinycell the width and length of the individual tracks and through to the deck of the board (DW style).

I would attach photos but I can't figure it out. Attaching jpegs doesn't work, nor does putting a link inside an image bracket so here is flickr. https://www.flickr.com/photos/28261840@N08/albums/72177720297583719

4
There is a non-intuitive aerodynamic fact where drag at low speeds favors high-aspect wings, and drag for high speeds favors low-aspect wings. Folks have been pushing the HA foils to the max, the only limit being too wide to turn, or too small to lift in lighter wind. I'm wondering if low AR wings have their place - not in terms of being forgiving and friendlier, but in terms of actually performing better from a physics standpoint at high speeds.



Above is a general chart showing total drag on the top line. The chart shows that lift-induced drag is the main source of drag at low speeds, and parasitic drag is the main source of drag at higher speeds.

Lift-Induced Drag is lowered by a HA wing (somehow...)
Parasitic Drag is caused by more leading edge interacting with the air/water - a shorter fatter wing is better for reducing this.

At low speeds, the high AR wing has LOWER lift-induced drag, and the low-AR wing has HIGHER lift-induced drag. Since HA wings have lower lift-induced drag, they perform better in terms of efficiency at lower speeds - the total drag is lower on the left hand side of the graph.

At high speeds, the lift-inducing drag is minimal, and the parasitic drag becomes the major source of the drag - this is the right hand side of the graph. A lower AR wing (larger chord), has HIGHER lift-induced drag, but a LOWER parasitic drag than a high-AR wing. So, once you have the power to get to the high speed, the lower AR wing is superior in terms of top speed and low drag.

This is why fighter jets have short fat wings and gliders have crazy high AR wings (+30AR?)/


Is anyone an engineer/physicist and know how this works in water? Is the crossover in terms of what the main source of the drag the foil is experiencing a thing that is relevant to foiling?
     i.e. is the crossover on the graph above at 20mph, or is it something like 200mph in water - and therefore not relevant to foiling?   

5
The Shape Shack / Ultralight wing board glassing schedule?
« on: January 21, 2022, 10:29:30 AM »
Hi all, looking for experienced opinions on a ~55L 46 wing board vacuum build Im trying to keep super light. I dont want a box failure but Id be fine with a board that dings easily.

Option 1:

2oz s glass entire top
4oz carbon/innegra whole top and rails
1/8 5lb divinicell standing area
2oz s glass standing area

1lb EPS CORE

3 x 4oz carbon innegra overlapping patches for foil box.
4oz carbon/innegra entire bottom and rails
2oz s glass entire bottom

Option 2: heaviest

Same as 1 but 1.5lb and no divinycell, just some patches over foot locations

Option 3: heavier

Same as 1 but divinycell entire top (and bottom?)

Option 4: lightest

Same as 1 but no 2oz S glass finish, just 4oz carbon innegra.

Other stuff:

- 1.5 thick HD foam track foil box
- Tuttle box through track box going to upper skin
- HD blocks under footstraps and leash plug.

Id like to finish as light as possible. All the fast guys in SF with custom boards have a peel ply finish with no pad. Im not sure how they seal from pinholes. I think if I glass the 2oz separately that should fill the pinholes from the lower layer, correct? Or do I need a micro bead/epoxy rub ove that as well? If I just finish with carbon/innegra (which cant be sanded) can I just do a microballoon /epoxy rub on that to finish?

I promise to post a build thread once its started to help other clueless newbies. Aim is February.


6
Im looking to shape a board in the spring using a vacuum to make a super light board to my specs. (50, 75L and under 10lbs with inserts). I think a wing board would be way more forgiving than a short board in many ways.

Id need an EPS blank or two at least 5 long, 5 thick and 26 wide.

Surfboard blanks are around 100$ and the vacuum and all the gear would put me under what a new wing board costs and future boards would be sub $500 to build myself, I would hope.

Does anyone know where to source this? Maybe get a giant SUP blank and cut it in half? All the blank companies in CA have nothing thick and short. Gluing two blanks together would add a lot of weight I would think.

Greenlight surf supply has them but they are located in NJ and shipping is $300.

Im not too far from Santa Cruz, CA.

I know a lot of folks had boards made by a certain famous winger in SF, and Clark makes them in HMB, but I dont know where anyone gets blanks!  ???

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