Standup Zone Forum
General => The Shape Shack => Topic started by: Beasho on December 03, 2017, 03:32:08 PM
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Things were great until they weren't.
The last 2 days I was solo out at Mavericks in the morning attempting some drops. Eventually moved inside and caught some screamers in the 10 - 15 ft range. I went down paddling for a wave and was sitting in a safe zone when a wave rose up I was thinking "I am safe waves don't break here. . . . I am in a safe spot . . . wave stands up . . Hey I am in a safe spot!" BOOM! A 10 - 12 foot lip came down on me with my board slightly behind.
Separation . . despair . . thankful the foil DOES actually float. Retrieval, then perplexity at how to paddle back in with this thing. . . . .
Long story short I think a combination of epoxy and maybe JUST gorilla glue to set back into place. The Divinycell box sheared in half. The carbon Tuttle is 100% intact. All I need is to re-adhere with something STRONGER than Divinycell.
The last 2 photos show the box and how it is sitting back in place. It's pretty snug. I'll just need to rebuild a bit of Styrofoam which is actually pretty easy when combined with Gorilla Glue.
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As my Tesla Engineer neighbors observed "Something has to break. Probably better this happens and you just put it back in than the whole board breaking apart or your foil snapping in half."
Good point. Maybe this is just par for the course in bigger waves. Another reason to aspire to the Gorilla glue re-installation. Quick and relatively painless.
Then I can put the effort into a solid upper and lower re-lamination with some Carbon patches.
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What it looked like from the Surf cam when I was foil testing solo at Mavericks.
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Wow. I'd be thinking about some sort of hd foam collar with an inside dimension to match existing to help hold it together and spread the load more evenly to the skin.
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Beasho, glad you're ok man. Stuff can be fixed.
I'm surprised that those boxes don't have a flange built onto them. Seems like a top flange would be a great idea on those Tuttles.
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That's why I put a big carbon patch on my foil board, top and bottom. To spread the load. I look at those long masts and big wings and see an impossible construction problem. No matter what you do there will be a failure point, but I'd like to move that up the force curve as far as feasible. Foam alone isn't going to cut it.
I think the entire Tuttle box notion is pretty silly. A perfect example of using something inappropriate because it was used somewhere else for a good reason. Windsurf foils use a Tuttle box--because it's already there! Windsurf boards use a Tuttle box for their fins because of all the force applied to their fins by the sail. The heavy sandwich construction and engineered support of a windsurfer Tuttle makes it OK for a foil--though it's probably not ideal there either. So surf foilboards, with their much flimsier construction than any windsurfer, follow along in the practice. That's just goofy. There is nothing about a Tuttle box--deep or otherwise--that makes it suitable for attaching a foil. The surprising thing is that it works at all.
If you were going to design a foilboard from first principles you would likely wind up with some sort of through-bolted plate to spread load top and bottom, with an hourglass tapered chunk of PVC to evenly distribute the load to the board surfaces, probably reinforced with tapered patches to reduce the stress risers created by the patch edges. At the very least a Tuttle cartridge with collars top and bottom like jRandy suggests--a neat solution.
A set of mast tracks installed in the bottom with best practices for distributing the load to just the bottom surface (PVC cartridge, glassed under) would be an adequate alternative. Last on my list would be a Tuttle box in a PVC cartridge, with reinforcement top and bottom to spread the load across the surfaces. I wouldn't consider a Tuttle in a cartridge installed without surface reinforcement. What's holding it in place? The edges of the surface and some EPS foam you can crush with your fingers?
Looking at the way your box failed I see no surprises.
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What about a double thick insert like I do then grind of the old foam of the box and route a Chanel in the center so you have the ability to run booth styles of mount?
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Spread the load - like a pyramid have a nice solid wide base. Get rid of the tuttle box and add mast tracks. Tuttle Boxes are good if you install it on a board with a lot of concave. This L41 was just glass/epoxy and had a lot of flex. I did a nice glass blend to mitigate the flexing.
(https://i.imgur.com/j5NTQZ6l.jpg)
(https://i.imgur.com/hcrzmFnl.jpg)
(https://i.imgur.com/uSrdAHyl.jpg)
(https://i.imgur.com/5lm66JCl.jpg)
(https://i.imgur.com/pobNPFal.jpg)
(https://i.imgur.com/aTvJIIql.jpg)
(https://i.imgur.com/aA0eK2ql.jpg)
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Here’s one of my tuttle box Reinforced install after a wreck. The
Layup held up, the box inside shattered and he bent his mast.
(https://i.imgur.com/1lAj9B8l.jpg)
(https://i.imgur.com/ndyAfqOl.jpg)
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No way to keep up with eDUBz repair jobs.
What I was hoping was that Gorilla Glue would serve as a quick and effective means to repair fin box installations serving as a foundation for the fin box in the foam.
In my example the Divinycell cassette holding the Tuttle box sheared. I did some test glueing Divinycell with Gorilla Glue and the results suggested the Gorilla Glue bond is stronger than the original Divinycell PVC foam structure.
https://youtu.be/LM-txMeTjPo
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Thanks for the video Beasho. It's good to know that Gorilla Glue is not the weak link.
I love it really enjoy when people beat surfboard materials with hammers on the interweb.
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Here’s one of my tuttle box Reinforced install after a wreck. The
Layup held up, the box inside shattered and he bent his mast.
(https://i.imgur.com/1lAj9B8l.jpg)
(https://i.imgur.com/ndyAfqOl.jpg)
Is the cracked Tuttle box a molded carbon box or one of the molded plastic boxes?
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I did some test gluing Divinycell with Gorilla Glue and the results suggested the Gorilla Glue bond is stronger than the original Divinycell PVC foam structure.
Note: This observation applies to the BOND, not necessarily the expanded Gorilla Glue foam.
For my purposes all I cared about was that the Gorilla Glue reconstituted the Divinycell cassette into a form that was as good as the original. Check the box.
The beauty of the Gorilla glue is that it expands but don't expect the expanded foam to be the same strength as the Divinycell. I did some further testing to show that expanded Gorilla glue has a density of ~ 1 lbs per cubic foot. Slightly more than Styrofoam @ 0.9 lbs per cubic foot.
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Thanks for the sharing your experiment Beasho. Could Gorilla Glue be used to repair a small areas were foam is missing instead of using a mixture of Micro-Balloons and epoxy to fill in a void in the foam?
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Thanks for the sharing your experiment Beasho. Could Gorilla Glue be used to repair a small areas were foam is missing instead of using a mixture of Micro-Balloons and epoxy to fill in a void in the foam?
Yes - HARD STOP . . . . 100% Much easier using Gorilla Glue than Epoxy and Micro-balloons.
There is a trick. You need to add 'kicker'. With Gorilla Glue this is a touch of water. I whip it in with a Dremel. Spray a few dustings and whip the glue until it turns lighter and aerated. What this does is to ensure the glue cures from within and doesn't form large gaps.
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Beasho, I like the Dremel idea. If I could only find mine...
I dropped a longboard on the end of a piece of angle iron that holds the lights on my trailer, making a L-shaped cut through the fiberglass and into the foam 1/2 inch (13mm) deep. Happened over the summer, I am just getting to this tonight as we approach Christmas.
I cleaned and sanded the area and made the corner of the wound just large enough to drip in the Gorilla Glue. I misted some water in the hole with a recycled spray bottle. I added a small drop of glue and another small mist of water then stirred with a toothpick. I did this a couple times. Tomorrow will be a trim and sand and first layer of glassing.
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Thanks for the sharing your experiment Beasho. Could Gorilla Glue be used to repair a small areas were foam is missing instead of using a mixture of Micro-Balloons and epoxy to fill in a void in the foam?
Yes - HARD STOP . . . . 100% Much easier using Gorilla Glue than Epoxy and Micro-balloons.
There is a trick. You need to add 'kicker'. With Gorilla Glue this is a touch of water. I whip it in with a Dremel. Spray a few dustings and whip the glue until it turns lighter and aerated. What this does is to ensure the glue cures from within and doesn't form large gaps.
Thanks Beasho! I was worried that there may be large gaps in the Gorilla foam, but your technique of getting a good mixture should solve that.
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See this video for how I mix up the Gorilla Glue.
This also has some estimates on resulting density ~ 4 lbs per cubic foot.
https://youtu.be/UgZ3A3igBbY
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Note: The cell structure of the Gorilla glue. It was most entirely filled in.
The Great Stuff formed a solid bubble, on top, but when I cut into the foam it was uncured and still wet beneath the top coat.
The problem with Poly glues is that while curing they insulate themselves from the moisture needed to cure the glue itself. Whipping the water into the Gorilla glue appeared to address the problem of large voids and uncured lower layers. Great Stuff alone would be hard to work with because it comes out already expanded where the Gorilla glue, mixed with a few sprays of water, starts out with a higher density and then expands to fill the cavities.
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Box repaired with Gorilla Glue.
Best thing to trim the gorilla glue is a sharp knife. In this case a constantly sharpened filet knife.
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Top deck installed a divinycell plug and then 5 layers of 6 oz cloth.
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2 Layers of 6 oz fiberglass followed up with 2 layers of 6 oz carbon patch.
Cutting the Tuttle hole can be a challenge. I used the black carbon cutting discs on my Dremel. I put blue painters tape inside the box to indicate the sides of the box and serve as a visual aid when I was getting close to the edge. I also put a disposable Styrofoam plug into the Tuttle to prevent any epoxy drips.
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I've been riding the repaired box for 2+ weeks now, a couple hundred waves up to 8 feet. No signs of any stress.
The moral of the story: Mentally prepare yourself, if you get hit by a big wave, for your box to rip out. The good news is that the repair can be less painful than you'd expect.
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Nice. The big carbon patches are a fine idea.
I got a little carried away with mine. Similar board.
(http://www.ponohouse.com/wp-content/uploads/2017/11/IMG_3146.JPG)
I'm sensing a theme here. I guess I like yellow, red and white boards.
(http://www.ponohouse.com/wp-content/uploads/2017/11/IMG_9856.JPG)
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Nice. The big carbon patches are a fine idea.
. . . . .
I got a little carried away with mine. Similar board.
Pono - Are you foiling yet?
Sam Pae 230# is flying around on the Maliko 200 and able to pump back to sea catching 2 waves for 1. Haley 240# has been successfully flying on Kai foil but would have been better off learning with an array of larger foils. I am about to pull the trigger on an Iwa and Maliko 200.
The latest theory is that the foil should be much, much more efficient than a schloggy surfboard. Big guys rejoice. Just get a larger foil and start flying. Weak link might be the boxes or the mast, maybe not.
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Thanks for the write-up Beasho, nicely done!
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My weak link is my dodgy knee. It's doing pretty well though, so I think it's time to jump in.
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Box repaired with Gorilla Glue.
Best thing to trim the gorilla glue is a sharp knife. In this case a constantly sharpened filet knife.
Nice repair and successful too.
Your knife is pointing at some large stress fractures that you haven't talked about, and I see in one of your photos that you laid some glass there (Starboard side extending half way from the box to the rail). That damage must be related to the box mount failure. I am interested to see how this area holds up.
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A question for anyone - Are the patches over boxes and tracks simply lying on top of them and connected only by epoxy? ie I don't see any fibre connecting box to deck / bottom laminates except for this overlay. It strikes me that both epoxy and fibre are being asked to do something it they aren't really designed to do.
I suggest that boxes be mounted such that they are slightly proud on the bottom (and top for Tuttles). Then Carbon tow strands be half-looped around them with the tails ending on the opposite sides of where they contact the box. The tails could be spread out radially. This way the forces would be directly transferred to the carbon tow in tension, then to the patches and regular laminates. Variation: if proud is no good, dig into the foam so the loops can contact the boxes, then feather the foam as the tow rises to the surface. Fill the voids afterwards if that is important, then laminate.
I also suggest that masts should be designed with a "fuse" or a "breaker", much like a release on a ski binding. Either an intentional weak/brittle spot that is easily repaired or a mechanism that can be reset on the spot. This just occurred to me so no suggestions as to how to do it. It would add complexity, cost, likely weight. And would take repair work away from eDubz, which none of us want.
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A question for anyone - Are the patches over boxes and tracks simply lying on top of them and connected only by epoxy? ie I don't see any fibre connecting box to deck / bottom laminates except for this overlay. It strikes me that both epoxy and fibre are being asked to do something it they aren't really designed to do.
I do two layers of carbon generally, the first is table wet and laid on loosely, razor cut in the middle, and then the mast track or box in its PVC cartridge is "buttered" with epoxy and chopped CF and pressed in, taking carbon with it along the sides. I roll the shit out of it to get the carbon flat and let it set until it's tacky, then roll it again, and add a second patch over the top and roll it to incorporate. I generally fill the slot with foam and trim the opening with a razor if I get to it while the second layer is still soft. I generally add a layer of 4oz to sand and then hot coat.
The board in this picture was a bit different because I added the Tuttle after the mast tracks were in place. I used a GoFoil pre-wrapped and layered Tuttle cut down to fit snugly between the tracks. I Gorilla Glued it in place, trimmed the top flat, and then just laid patched over the inserts. I'm counting on the well-anchored tracks to support the Tuttle. It's been well used and abused by others, so I think it's fine, but we'll see what happens with my fat ass on it and a monster foil attached.
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personally I don't think the carbon is really all that necessary. The problem I see with this type of Tuttle box is you are relying on the end profile of the carbon Tuttle box to bond to which is very small and the failure will probably come when that point goes. What I like to do when bonding things like this is to create a internal fillet between the two parts by chamfering a small amount of foam from around the part and then using some epoxy/fiber paste as the fillet before laminating there quadrupling the amount of surface you are bonding too.
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I can see how Supuk and Pono's methods add a lot of surface area to bond to. Note however that every photo on this thread shows minimal box to laminate contact area.
I am amazed that large fins, leash plugs and foil mounts don't fail more often. Maybe they do, but maybe better a leash plug than a leg, or a foil mount than a snapped board.
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I can see how Supuk and Pono's methods add a lot of surface area to bond to. Note however that every photo on this thread shows minimal box to laminate contact area.
This might be the case if the Tuttle were a standalone Carbon Fiber box shape. However the Tuttle is mounted in a Divinycell cassette. This ostensibly transfers load laterally to Divinycell that is much harder than EPS foam. The Top and Bottom laminates can then be adhered to a larger surface area of Tuttle and Divinycell rather than just the lip of the Tuttle.
In my case the entire Cassette sheared in half. However the wave I got hit by could have broken a regular SUP. There is only so much you can ask in heavy conditions.
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I can see how Supuk and Pono's methods add a lot of surface area to bond to. Note however that every photo on this thread shows minimal box to laminate contact area.
This might be the case if the Tuttle were a standalone Carbon Fiber box shape. However the Tuttle is mounted in a Divinycell cassette. This ostensibly transfers load laterally to Divinycell that is much harder than EPS foam. The Top and Bottom laminates can then be adhered to a larger surface area of Tuttle and Divinycell rather than just the lip of the Tuttle.
In my case the entire Cassette sheared in half...
I suppose it spreads out the load a bit, and keeps fibre aligned under higher loads better than styrene, but if the Divinycell was seriously strong, it wouldn't have failed there. You should have a mass of white foam firmly adhered to an intact high density foam box with a matching hole in the board.
EDIT - I just went back to the photos - and the mass of missing white foam is what you have on one side. The HD foam on that side is intact. I suppose we don't know whether it was the deck bond or the bottom bond that went first, but the failures of the foams are very different on each side. I also figure that there was some fore/aft force as the damage of the deck laminate is not even. EDIT 2 - the mast was forced backwards is my guess. Interesting that it took some glass with it, likely from the bolt/washer pulling it down. I suspect the fracture in the HD foam is from tension forces and the intact side is mostly compression. Maybe there was a defect too. Maybe there was some Z-axis force too.
... However the wave I got hit by could have broken a regular SUP. There is only so much you can ask in heavy conditions.
I agree - it broke at its weakest point. After the bolt/washer pulled the deck laminate, likely the deck laminate to box bond second, then something on the bottom (I think you cleared away some of the damaged bits) then sheared through the rather brittle Divinycel with some sideways force on the mast.
Hence my suggestion that a fuse or breaker switch be designed in to the mast which could be easily repaired or reset, rather than the board. Belay that - a jagged stump of a mast could be lethal. Maybe a mount that could release sideways and fore/aft and be clicked back into place. I predict Hobie will be the ones to do this first.
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Good thread. Thanks.
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Mast tracks 4.5oz or fin boxes 3.8oz. Are the mast tracks that much stronger? I've busted mast tracks at Waddell Beach windsurfing. Just curious....
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I've been making my own Tuttle boxes which up to this point have never failed. Basically foam with carbon cloth stiffeners which also lock into both hull carbon and deck carbon. white foam is EPS 2.5 lb, Yellow foam is 2 part polyurethane mixed and poured and shaped. 3K carbon twill. all wrapped in 6 oz fiberglass x 3 layers. Insert this cartridge into board.
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Has anyone tried this:
https://vimeo.com/117131100
or know of any other adjustable tuttle box?
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I've been making my own Tuttle boxes which up to this point have never failed. Basically foam with carbon cloth stiffeners which also lock into both hull carbon and deck carbon. white foam is EPS 2.5 lb, Yellow foam is 2 part polyurethane mixed and poured and shaped. 3K carbon twill. all wrapped in 6 oz fiberglass x 3 layers. Insert this cartridge into board.
This is crazy (good)! Do you have any more detailed photographs of the "Tuttle Cassette?"
I can't picture what is going on from the photograph. Are you building your own female "Tuttle frame" out of carbon somehow and then building the cassette all from scratch?
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Yeah, between Peter and Surffoils the Zone has some pretty serious designers.
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Has anyone tried this:
https://vimeo.com/117131100
or know of any other adjustable tuttle box?
That’s pretty slick, a plate adaptor without extending the mast height.
There are a couple of Tuttle to plate adapters around. Even a GoFoil seems to be joining the plate camp.
https://blueplanetsurf.com/products/tuttle-to-plate-adapter-by-manta-foils/
https://gofoil.com/adapter/
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For this Tuttle Box I used two solid sheets of 4mm? carbon sheet purchased from ebay. This is a prefabricated and cured gloss carbon layup. I clamped these two pieces to either side of the mast insert portion. The sheets over hang the insert by approximately 1 cm. ie.- They are 1cm larger than the insert, front, back. The length of the cut sheets is as long as you need to reach from the bottom of board to the top of board. About 5-6 inches for my board. Use a generous amount of release agent on the mast insert portion. I then used a mixture of epoxy resin, milled fibers and aluminum powder to fill the uncovered gap in the front and back of the mast insert. Once that cure I file to shape and then vacuum bag 3 layers of 3K carbon twill over the sanded sheets and fill, to lock it all together. When done and removed from mast insert, I then surround this piece in 2.5 lb EPS foam. Square it up. Cut v channels out of foam and lay 2 layers of 3K carbon into V channels. I use separate small pieces for each channel. I also use melamine boards with release agent to clamp to the sides to maintain a flat shape. Once cured, fill the V channel gaps with 2 part polyurethane9 4-5 lb density. Wrap the entire cassete or block in 2-3 layers of fiberglass or 1 layer of 3K carbon and its done. Yes it takes time, but I find them to be bomb proof.
P.S. when inserting this cartridge I use a dremmel tool to cut channels in the boards foam, perpendicular to the cartridge insert, maybe 1-1.5 inches long by 4mm wide. I then fill these channels with a mix of milled fibers and microballons to offer buttresses to the cassette. I have always done the same to my side fin boxes and have had great results. Maybe 5 channels per side.
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Here is a picture of my 1st one without the carbon top and bottom cover cloth. Only used 3-4 layers of 6 oz glass, top and bottom. Maybe this will make more sense.
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Very cool design Peter. When I grow up I'll be that exacting and patient.
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Great work man. Really detailed design.