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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       12-30-2009, 8:33 PM Reply   
Hollow boards have been around in sailboards and surfboards for a bit. I built one a few years ago using 9 oz CF and 1/4" end grain e.balsa that was wayyyyyy stiff and heavy - close to 8 pounds.

There are currently two basic hollow carbon construction methods. Hydroepic and Kolstof used aluminum honeycomb on the deck and some form of internal stringer glued in. The boards are built in half's and the internal structure glued in and finally the two pieces glued up.

The other is the aviso, which builds using high density foam skins inside a mold, that is layered up on a bladder. Once the mold is loaded the bladder is inflated pressing the components against the mold surface.

The Aviso website:

http://www.avisosurf.com/TechAdvantage.html

The Hydroepic website showing the cutaway for the internal frame:

http://www.hydroepic.com/techaeroflex.php

The Aviso cross section:

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       12-30-2009, 8:45 PM Reply   
Aluminum honeycomb is seriously expensive, a single sheet enought for my build would run close to $400 retail...so I won't be using that material. :-) My choice for this build will be similar to the Aviso. HD foam skins between layers of CF.

In my prior hollow CF build, I used a lost foam method - I will build the board and then, when it's laminated, I'll drill a hole into the foam and fill that with Xylene (solvent) to remove the foam and leave a "mostly" hollow interior.

I am using some residual offcut 1 pound foam.
When I get a 4 x 8 sheet, I can get 2 - 2 x 5 pieces and then this 3 x 4 setion. The outline of the board will fit diagonally, but I have to cut two parallel sides so that I affix the hotwire templates and get a plumb rocker cut.

I place the board template on the board to assure that I have enough material...after tracing the outline, I draw two parallel lines which I will cut on to give me the surface to attach the hotwire templates.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       12-30-2009, 8:54 PM Reply   
I cut the straight's using a circular saw. I attach the template using a center mark on the foam, as well as, the templates. The mark is 2' off the nose, but it serves no purpose other than alignment, so it could be 3 feet off also. You'll note that I screw the template in close to the deck side. The reason I do this is the screws are so long they are into the outline. I will have to shape a ton off the deck and will remove the areas of foam that have the screw holes.

The rocker hotwired.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       12-30-2009, 8:58 PM Reply   
Next I cut the outline using a jigsaw. I use a sanding block to clean up the vertical surface and bring it down to the outline.


Outline and rocker in, tomorrow I'll shape the deck down and the rails.

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Old    Lakewakes Wakesurf Boards (brewkettle)      Join Date: Jan 2009       12-31-2009, 4:49 AM Reply   
need a copy of that rocker profile
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       12-31-2009, 5:25 AM Reply   
You have a keen eye Jim Beam. I'm trying a new rocker on this, attempting to match the shape of the board to the method of construction. IMO, one of the issues that plagues the pop-out manufacturers is their marketing model. They use shapes from big name shapers but the original was shaped in PuPe, the composite construction is significantly different. In particular the hollow boards have "weird" flex patterns compared to PuPe or EPS and Epoxy, so while it may LOOK like a duck, it doesn't ride the same.

Some of the propaganda from the sites of the two manufacturer's, mentioned above:

This is an interesting demonstration of the deflection of the board. On the bottom view you can see a single concave formed.

http://www.avisosurf.com/FEA.html#topview


The Hydroepic folks designed the bottom to morph shapes, principally the bottom would morph from flat to single.

http://www.hydroepic.com/techhull.php

"Traditionally, surfboards have been one solid object - top and bottom connected by foam, with one primary mode of resonance. Shapers have partially solved this previously unidentified problem by shaping specialized bottom contours, which help water flow smoothly as it travels beneath the board. We now introduce an independent, interactive bottom contour - the DynamicHULL™. It gives the hull it's own mode of resonance, enabling tiny adjustments to prevent water lamina from breaking into turbulent flow - less turbulence means less drag and more control."

The Aviso folks theorize that you can load the board up and as it unloads the board will shoot forward - we've referred to that phenomenon as "pop" - that's with one "O". :-)

http://www.avisosurf.com/TechAdvantage.html#NextGeneration

"Since the deck is not directly connected to the bottom, the deck absorbs and stores potential energy and kinetically propels the surfer swiftly and efficiently, allowing an almost constant state of acceleration to be realized by the rider. The flex characteristics of the boards are significantly positive and confer independent flex dynamics. Carbon fiber has remarkable flex memory with a ideal “coefficient of restoration”, a property inherent in any rigid structure that allows it to return to its original state after a physical force is applied (How much a material flexes & how fast it flexes back). Analogies in sports include the technological transition from wood to carbon graphite tennis rackets and bike forks from aluminum to carbon fiber."

Anyway...it seems to me that the board should be shaped to take advantage of the materials used in the construction. So with this build, understanding that the nose and very tip of the tail can be made to flex independently of the rest of the board I've changed the rocker. Flat'ish when unloaded to maintain speed, increased rocker when loaded into a turn. Not much deflection, I'm guessing maybe less than 1/8".
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       12-31-2009, 8:23 PM Reply   
I measure and plot the thickness in several spots and then freehand the foil.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       12-31-2009, 8:26 PM Reply   
I use my hotwire to get close and I try to be careful, so that I can get two "cores" from the single cut.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       12-31-2009, 8:30 PM Reply   
Sanding blocks and surform to shape it. 1# pound is EASY to overshape, so slow and easy is the watch word.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       12-31-2009, 8:32 PM Reply   
All shaped up.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-04-2010, 5:05 PM Reply   
So disaster struck. Woofie, my shop dog, almost never barks, which is both a good and a bad thing. He doesn't disturb folks, but it makes him hard to find also. Anyway, I locked him in the shop for a few hours and when I couldn't find him, checked the shop. There he was, all snuggled up in several large pieces of the blank pictured above.

I hesitate to "say" that he was pissed at me, but I have to tell you, if I got locked in a shop for a few hours with a fresh blank that took hours to make, I'd rip it into chunks and take a nap on it also! :-)

This project is on hold until I score some additional EPS AND remember to check for woffie before closing the door. :-)
Old    Is it summer yet? (trentj6930)      Join Date: Oct 2007       01-04-2010, 7:36 PM Reply   
Thanks for the laugh! I was hoping to see some progress....but that was even better!!!
Old    dtw. (notsobueno)      Join Date: Dec 2004       01-06-2010, 10:42 AM Reply   
Are we entirely sure that Woofie isn't on Mrs. Surfdad's payroll?



Should we check Woofie's offshore bank account(s) for large recent deposits?
Old    Andrew Taft (taft)      Join Date: Jul 2006       01-06-2010, 3:32 PM Reply   
It looks like California had a whiter Christmas than we did up north.

You need to get Mike Rowe out with you one day Jeff
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-06-2010, 7:55 PM Reply   
@ trentj6930 - I had to laugh too, to keep from crying! :-)

@ notsobueno - you know, now that I think about it, woofie does seem pretty cashed up!

@ taft - at least for woofie! Who is Mike Rowe?

Out of foam, I started to get the shakes and started "seeing" things. :-) So I swung by Lowes and picked up a two sheets of Insulfoam. One 1/2" and one 1". Total cost was $16 and it should provide 2 blanks, maybe 3.

Here I've already cut the foam into sections. In the second picture it's hard to see, but I've laying up a panel of 3/32" e.balsa sandwiched between the two pieces of foam.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-06-2010, 8:02 PM Reply   
Before gluing up, I peeled off the barrier plastic on one side. Then spread some glue or epoxy. Gorilla Glue works well, as does a decent epoxy.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-06-2010, 8:06 PM Reply   
I tape the sandwich up and then slide it in to the bag which also has my rocker bed. Pull a vaccuum, cover it with a blanket and tuck it in for the night. Oh shoot...where is woofie?! :-)

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-06-2010, 8:19 PM Reply   
The theory behind this build: I was chatting with Josh Dowling of Josh Dowling Shapes in AUS. He was the part of the R&D team of Firewire surfboards and then helped in setting up the factory for Sunova in Thailand. The discussion centered around increasing pop and Josh suggested using e.wood skins and inserting a layer in the middle. Mitch was discussing the construction of integrity wakeskates and they use a laminate of bamboo in the middle. Inland Surfer's have two layers of veneer, I believe they are 1/42" pine one top and one bottom. Arguably, the e.wood adds stiffness and "possibly" can add some pop when sandwiched in the middle, as well as, on the skins.
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-07-2010, 5:25 AM Reply   
Out of the bag this morning and there was no "springback". There is an interesting phenomenon when you glue up three of more pieces, the resulting structure is very stiff.

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Old    Jonathan Tollefson (jon_tollefson)      Join Date: Oct 2005       01-07-2010, 8:39 AM Reply   
Oh man, So glad to see that other people use foam from Lowes or Home Depot!! I was thinking I was the only one, and I am glad you were able to understand woofies emotions!!

Jon T
Old    Show (bigshow)      Join Date: Feb 2005       01-07-2010, 6:06 PM Reply   
I'd love to see a board with the original ink from the foam visible as the art:-)
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-07-2010, 7:49 PM Reply   
Like an old clark blank? This is a plastic barrier, wouldn't be good for lamination. :-)

I create a centerlune to align the outline template. I also have a tail stop, which I align based upon the apex. Lay the outline template on the marks and draw that on the foam.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-07-2010, 7:51 PM Reply   
Jigsaw to bring it down to the outline.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-07-2010, 7:54 PM Reply   
It shaped up easy, a few passes with the plane takes it down.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-07-2010, 8:09 PM Reply   
Hey Jon,

Yeah - woofie was headed to the shrink, but I think now he's all better. :-) Nothing like destroying personal property to make a dog feel better. :-)

That foam is thge C grade beads - rather than the B - huge beads, but it's a fairly light density, maybe .75 #.

One thing that is interesting is using the flat pieces to form a rocker. Buying just the thickness needed saves a ton of waste and $'s, plus it's a easy to find as the closest Lowes/Home Depot.
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-12-2010, 8:39 PM Reply   
Back to the HCS. Rocker cut and I have aligned a template that I'll use to cut the bottom HD foam. The template is inboard of the outline, as you can see in the first picture from Hydro Epic at the top. The rails are only multiple layers of CF, while the bottom and the deck have a sandwich of HD foam between layers of CF.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-12-2010, 8:44 PM Reply   
The stiffness of a board or any sandwich composed of skins or facings is affected by the distance between the skins. The Hydro Epic uses the HD foam to increase the distance between the layers of the facing, which adds a little stiffness. I've decided to go with a 1/4" HD on the deck, where the greater loads will be present and 1/8" on the bottom..

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-12-2010, 8:49 PM Reply   
Devil dog - NOT locked in the shop. :-)

The bottom skin cut. I'll shape the bottom concave such that the skin is imbedded in the foam and the rails are flush with the bottom skin.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-13-2010, 8:19 PM Reply   
I adjusted the HD skin so that it would be inset to about the distance of a normal lap. I outline that on the bottom of the foam and then route it out to 1/8" depth.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-13-2010, 8:28 PM Reply   
With the goal being a hollow core, I need to support the fin boxes to prevent movement side-to-side. I opted to insert some HD insert for the fin boxes.

In retrospect, I'd do these before routing the HD skin insert.

I don't want to use much epoxy, because it won't dissolve during the lost foam process, so I'll just tack the Corecell fin box inserts, enough to allow me to shape them.

I roughly locate the fin boxes, cut the material oversize about 1/2" all around, then route the foam where the insert will go.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-14-2010, 7:59 PM Reply   
Yeah - fin inserts first! :-) I think if I were to do this again, I'd form some CF cups that the boxes would fit in.

Core shaped and ready to bag the bottom skin to the core.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-15-2010, 8:07 PM Reply   
The underlayer is 6 oz carbon, well actually this build will be with all 6 oz carbon. This section of CF weighs 5 oz and I mix up that much epoxy - trying to achieve a 1:1 ratio of CF to Resin.

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Reduce, reuse and recycle :-) Last build bag becomes this builds wet out table. :-)

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-15-2010, 8:10 PM Reply   
I used some scrape peel ply to help wrap the rails - just so I can slide it into the bag.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-15-2010, 8:12 PM Reply   
In the bag - just a section that shows the bottom inside layer wraps the rail.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-15-2010, 8:20 PM Reply   
In the prodution borads - hydro epic and avisio, the bottom of the boards are designed to flex - to adjust to the flow of water and actually create a concave.

You can see and read a LOT of hype about carbon in boards, but a few layers is pretty flexible, just less flexible than fiberglass :-) For this build, I am planning 3 layers on the bottom and 4 layers on the top, all layers wrapping the rail. That will be @ 42 oz of CF on the rails. The design, that I am borrowing, creates a super stiff deck and rails, with bottom that morphs to conforms to the water underneath it. Concave for speed going straight and then flat'ish in turns or when sliding.
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-16-2010, 5:31 AM Reply   
I had a few high spots I had to knock down, but "mostly" it came out as expected.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-16-2010, 5:45 AM Reply   
In a production environment, the "shell" is built from the outside in. That is the outer most layer is laid into the mold first and then successive layers work towards the inside of the board. I am doing exactly the opposite, working from the inner most layers outward.

In a hollow board, the rails become the weakest part of the structure. Even in a board that isn't hollow, the rails carry the majority of the load in turns and in landing from aerials. Traditionally this has been addressed by rail laps (overlap of fiberglass from top to bottom and vice versa). In this build, I will be afforded an opportunity to interleave the rail laps (bottom, top, bottom, top, bottom, top, etc). I believe in a molded environment that interleaving would be difficult to achieve. Hydroepic's originally had a part line along the rails and that is where they failed most often. They finally moved the part line to the bottom.

Aviso somewhat interleaves like this, they load layers of carbon then an inflatable bladder, then finally the opposite side carbon. The effect is more similar to a standard lay up, with rail laps.

I am going to alternate the bias with each successive layer 0, 90, 0, 270 the theory being that I'll distribute loads more effectively.
Old    Lakewakes Wakesurf Boards (brewkettle)      Join Date: Jan 2009       01-17-2010, 8:12 AM Reply   
i like the smooth CF lap look
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-17-2010, 11:46 AM Reply   
yeah - cosmetically CF is hard-to-beat.

In the build: it's lather rinse repeat. I didn't get good pictures, but under the top skin is two layers of CF. I've done my best to lay them up on a bias, as described above.

DO NOT attempt to wet the fabric and lay it up individually unless you have help, it's HARD to smooth out wet fabric ON wet fabric. Two folks can drape the cloth smoothly. If you are doing it on your own, wet both pieces outand gather them together and lay them up as a single unit.

When I do it this way, I lay some resin on the wet out table, lay the first ply down and then lay both pieces down. I wet as normal, but take lots of time to be sure that I have complete wet out.

It's in the bag curing.

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Old    Lakewakes Wakesurf Boards (brewkettle)      Join Date: Jan 2009       01-17-2010, 1:29 PM Reply   
so will you remove the top HD foam skin to dig out the shell then install some ribs to hold a monocoat film then lam the whole thing
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-17-2010, 4:57 PM Reply   
That's a cool idea! Sadly, my plan is more pedestrian. After it's all lam'ed I'll drill a hole for the vent and use that to pour Xylene into the EPS, melting it and leaving the board hollow.
Old    Lakewakes Wakesurf Boards (brewkettle)      Join Date: Jan 2009       01-17-2010, 6:09 PM Reply   
just like on your first build , will you then plug the hole with a vent valve and patch the second
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-17-2010, 6:27 PM Reply   
Exactly! FoamEz is licensing the goretex vents and I'll use the post-lam flavor for the hole towards the tail.

3 layers of CF. The core is sealed at this point. I need to blend the area between the HD foam and the rails then it's ready for final exterior lam.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-22-2010, 7:45 PM Reply   
One handed - there is a slight gap between the EPS and HD foam, I filled that with Bondo so that the final external lamination is smooth. Bondo is polyester resin, which shrinks ridiculously - however, once the final external epoxy/carbon is cured it won't matter if the bondo separates.

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Old    Lakewakes Wakesurf Boards (brewkettle)      Join Date: Jan 2009       01-24-2010, 8:12 AM Reply   
auto paint stores carry better brands of plastic filler that might not shrink at all , compared to the standard BONDO filler from the px
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-27-2010, 5:22 AM Reply   
Getting closer. I left a slight indentation on the deck to give it a look similar to the Avision Cole Trunk Board. The vast expanse of CF is boring to me, I kind of like the rail indentation. :-)

Coming out of the bag

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Evidence of the peel ply! :-)

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The rail indent.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-28-2010, 7:51 PM Reply   
Layer 5!

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-29-2010, 7:43 PM Reply   
At 5 layers it's pretty stiff...not sure if I'll add the last layer on the deck, it currently weighs 3 pounds, so I have room for the second deck layer.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-29-2010, 7:50 PM Reply   
Super stiff Carbon!

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Not :-) A single layer of 6oz CF in Epoxy just isn't super stiff as the hype machine trys to make folks believe.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-31-2010, 5:53 PM Reply   
I opted to double the deck external layer, it felt a little sponge'y under the rear foot.

The rails felt solid at 5 layers, so 6 layers should be good. After consildation, that should be .054" thick...close to 1/16"

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Old    Lakewakes Wakesurf Boards (brewkettle)      Join Date: Jan 2009       01-31-2010, 6:12 PM Reply   
i like the 7 layer myself
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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       01-31-2010, 6:21 PM Reply   
LOL - that's funny.
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-01-2010, 8:03 PM Reply   
It's hollow now. :-) I start by drilling a 5/8" hole that will eventually hold a vent. Hollow boards need a vent to drain any water that might get in and also to equalize the pressure - especially with a black surface.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-01-2010, 8:05 PM Reply   
I tape over the area I will be drilling, just in case of the bit spinning off.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-01-2010, 8:09 PM Reply   
The lost foam method involves melting the eps. It's lightweight 1# so doesn't take much. I've found that Xylene is the best at dissolving all the eps and also the quickest.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-01-2010, 8:14 PM Reply   
I then proceeded to fill the board with 1/2 gallon of the Xylene. I agitate it to make sure that I get all the EPS in the various nooks and crannies. You can hear it sloshing around, this is one of the characteristics on the water - it has a drum like resonance. :-)

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-01-2010, 8:19 PM Reply   
The vapor of the Xylene is very strong and continues to melt the EPS, so I tape the vent hole to keep the vapor inside. By tomorrow morning, there won't be a trace left of the eps.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-06-2010, 5:40 PM Reply   
I let the xylene evaporate and then flush the interior with a garden hose :-) The water jet gets the last little bit of residual foam out.

Once that's done, I tape the area where the fin boxes will go, drawing the location on the tape.


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The holes cut for the boxes.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-06-2010, 5:48 PM Reply   
This will be a weakness in the board - just a poor design on my part. It needed some way to seal off the fin boxes inside the board. I think molding a cup for the fin boxes would be the best bet.

This picture gives a visual of the hollow interior.

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-06-2010, 5:53 PM Reply   
5 minute epoxy isn't the best stuff, it's not total crap either, it's just too soft, but it does set up quickly. :-) With the weather and cooler temperatures, it's my best choice. I slathered everything up and set the boxes in the holes.

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Old    Brian (TXSurf) (bac)      Join Date: Feb 2008       02-06-2010, 6:00 PM Reply   
Very interesting build to follow Jeff

Looks like it turned out well though!

Can't wait to hear about how it rides
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-06-2010, 6:18 PM Reply   
The last little bit is the vent. I opted for a cheap $4 screw type rather than the $26 goretex vent. Now if I can just remember to take out out when it needs to be open and screw it back in before it fills with water :-)

The vent by itself and then an upside down picture of the board - it started to rain midway thru the install and I had quite the mess going on. :-)

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Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-06-2010, 6:34 PM Reply   
Thanks TXSurf and thanks for following along. The Aviso propaganda page has this to say:

"Since the deck is not directly connected to the bottom, the deck absorbs and stores potential energy and kinetically propels the surfer swiftly and efficiently, allowing an almost constant state of acceleration to be realized by the rider. The flex characteristics of the boards are significantly positive and confer independent flex dynamics. Carbon fiber has remarkable flex memory with a ideal “coefficient of restoration”, a property inherent in any rigid structure that allows it to return to its original state after a physical force is applied (How much a material flexes & how fast it flexes back). Analogies in sports include the technological transition from wood to carbon graphite tennis rackets and bike forks from aluminum to carbon fiber."

I think there is some truth to concept, but like most manufacturers of boards these days it's into mostly hype. The bottom of this board is flexible...well not really flexible, it can change shape when pushed on with some force, but comes right back.

In theory, the bottom will form a concave when in trim and riding flat down-the-line, but turn hard and that concave changes, deeper on the inside of the turn and flatter on the outside. The ability to have the bottom of the board "morph" is super techy, but we'll see how that works behind the boat. :-)
Old    dtw. (notsobueno)      Join Date: Dec 2004       02-07-2010, 7:18 AM Reply   
I may want to try this board, Dad.
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-07-2010, 7:23 PM Reply   
Absolutely dtw, I'll ship it down with Dennis next time he is southward bound. Or you are always welcome on our boat.
Old    dtw. (notsobueno)      Join Date: Dec 2004       02-07-2010, 8:15 PM Reply   
Thank you very much, but wouldn't that be past the limit of goofy riders on your boat....assuming Dennis and I were both there?



If Bryan AND I came up to your boat, along with Dennis, we could easily stage a mutiny.
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-07-2010, 8:27 PM Reply   
Yeah - only 2 goofy riders on the boat per session, so that means Bre couldn't be crew. No, no, no...you, Bryan and Dennis would NOT be allowed to congregate that close to gasoline. :-)
Old    Jonathan Tollefson (jon_tollefson)      Join Date: Oct 2005       02-08-2010, 10:00 AM Reply   
Interesting build Jeff! Can't wait to hear how it rides. No fancy paint job on this one?? Nice work. Jon T
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-08-2010, 4:41 PM Reply   
Thanks Jon - I like that adjective - fancy. I'd like to refer everyone to this terminology when making reference to my artwork - it's FANCY, to be used in lieu of crappy or ghetto or what was it that Mitch said - sacrifical altar. That was FANCY Mitch! :-)

I'm looking forward to the ride also...I'm giving it an 80% chance of success. :-)
Old    Lakewakes Wakesurf Boards (brewkettle)      Join Date: Jan 2009       02-08-2010, 6:33 PM Reply   
Surfdad,
on the fin box issue , you need to put a hd faom insert that goes all the way to the top deck so the cf will bond to it. it will be bonded at top and bottom of the board
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       02-08-2010, 6:49 PM Reply   
Actually while that is a good idea, it defeats one of the design principles - the deck and bottom flex at different rates/places/etc. The deck and bottom are specifically NOT attached to allow that flex and the morphing bottom feature. I SHOULD have made the HD thick enough to completely encase the fin boxes, though, which is what you had in mind, I'm sure.

When I was designing it, I thought - I'll route into the hollow so that I can get all of the Xylene out AND flush the residual out with the garden hose! :-) After routing it out I thought - oh yeah, that's going to be a great source of a future leak. :-)

I still like the idea of formed CF cups that would seal off the board, provide a solid surface to adhere to and...a solid non-flexing anchor.

Thanks for the input brewkettle!
Old    Jeff Walker (surfdad)      Join Date: Sep 2004       03-28-2010, 6:53 PM Reply   
Well it worked! I did a crappy job of placing the traction down, so James had a hard time riding it. In this small size, the Hollow is heavy - it takes a bunch of carbon to create the stiffness necessary to support the skins...this board was maybe 6'ish+ pounds. The bottom flexed as indicated above. It's a weird feeling, shifting back and forth moved the "concave" which tended to force the rider to ride the board further forward. In short, though, without the internal structure, carbon is just a really expensive FRP.
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