Balsa epoxy sandwich boards

What works & what doesn't and in what type of conditions. Got a "secret" only you and your shaper know???? Post it here... we can keep it quiet ;-)

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Shelfbreak
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Balsa epoxy sandwich boards

Post by Shelfbreak »

Noting pictures of the impressive balsa epoxy sandwich board Marky V has posted I feel compelled to ask some basic questions. You may also have seen pictures of the board Sunova built for Kelly Slater at Swaylocks
http://www.swaylocks.com/forum/gforum.c ... tt_id=9568

Few months ago my interest was initially stirred looking at the epoxy thrusters in local shops wondering if anyone was offering kneeboards of that construction. This lead to Swaylocks, jpegs of people standing on mals that flexed without breaking etc. I contacted Sunova about getting a custom kneeboard built - having read impressive reviews of their stand up boards. Unfortunately they had sufficient orders on their books.

1) For those who have ridden balsa epoxy sandwich, or for that matter EPS/epoxy kneeboards how do they compare with PE/resin boards?

2) Could this composite approach offer an alternative path to flexibility akin to a spoon but without the neutral buoyancy issues?

I know Swaylocks is the key forum for such discussions but as a bit of a design novice, I have found it hard to digest all the information on these new approaches in terms of utility to kneeboard design.
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pe?

Post by skansand »

i PRESUME YOU MEAN PU (POLYURATHANE) NOT PE (POLYETHYLENE) THAT WOULD BE BODYBOARD MATERIAL......HMMM PE KB's I WONDER...
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Post by doc »

Ahmmm- as one who may well be making some of the more confusing statements over on Sways, lets see if I can say it in normal english. Let me know if I get into jargon, etc....

Now, what that is is ( I think ) a fiberglass/epoxy/balsa/epoxy-or-other-adhesive/polystyrene foam board.

Balsa is...okay, but there are other materials to make your outer sandwich from, notably certain denser foams which can be sandwiched between glass/epoxy layers over a very light styrene foam core - the core kinda goes along for the ride. The strength and the flexibility are all in the skin. Though they are in a regular glass/foam board anyhow.

Flexibility akin to a spoon-type board? Well , yeah, with some serious deck shape and such issues, you would want a spoon-like very concave deck, mebbe play the foams you used as inlays here and there of different foams such that their flex and stiffnesses could be used to make the board flex in the way you wanted it to. With a standard convex deck the deck will buckle, badly, if it flexes much.

I will note that one of the really nice things about a flex spoon or similar board is that the flex can be easily 'tuned, with grinding off glass or adding more. On a composite board as you describe, tuning the flex would amount to making another board a little differently. 'Cos you would have to change the glass and change the foam and how it was done in maybe other ways.

As for epoxy kneeboards - well, I'm sure they are out there, just as I am sure Bud has made at least one. O know a local guy made an epoxy/Clark foam board not long ago, haven't heard much about it as yet.

anyhow- that's a beginning. Maybe you might want to ask some more questions and I can take a stab at it.....

hope that's of some small use, anyhow

doc...
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Post by Shelfbreak »

Thanks Doc

Appreciate your advice. I note your point about the ability to fine tune a spoon through judicious sanding. I take my hat off to those building spoons however I dont think that's my forte.

Nevertheless the thought of some flex appeals and in this regard I have wondered what a kneeboard built by the Bert Burger technique might be like. I note that he has joined forces with Nev Hyman (a well known shaper in Aust) to build custom sandwich construction boards on the Goldy.

I've since lodged an expression of interest about joining their fairly long queue - hope they accept the challenge. Seems sort of funny placing an order based on construction technique rather than kneeboard design credentials. Oh well nothing ventured.....
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Post by doc »

Uhmmmmmm - yeah, that'd work, sort of. The trick is in the foam selecton vs countours of the board - you may have been looking at the 'neutral axis' thread, which is interesting on these lines.

Image as a notional sketch of such a board.

Now, there's several who have been working with this from our lot, notably Terry Hendricks, who was working with it all long before it became fashionable.

I will also note that low or neutral buoyancy isn't neccessarily a bad thing. All the 'duck diving' stuff becomes moot. And there's more advantages. You might want to try something more conventionally flexy before committing .

hope that's of use

doc...
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Post by DrStrange »

Hveing just built and ridden a GG style edgeboard w/ neutral bouyancy I can say--there is a down side to low floatation: you cannot repeat NOT paddle faster than a seaslug can slug. You can't chase peaks. If you are 10 feet out of postion at the starting gun, you won't catch the wave. Maybe even 5 feet. If there is anyone else around, you cannot jocky for position. The only time a neutral bouyancy board is good is in an X marks the spot take off zone like a point breat or somewhere like that secret south swell spot on west side of Santa Cruz or that Elephant seal south swell spot or the harbor (can I say "the harbor"), but then you have the crowd factor.

I'm in the research and planning phase for my next project which will have flex tail only and max foam otherwise to hopefully compromise and get some of the best of both. But being in the water up to my neck and having max non-wave riding speed be less than a swimmer is not so fun at most breaks most of the time.
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Post by quadfin »

As in all board designs, the spoon has it's downsides. But what a sweet feeling I remember when that board just seemed to fold up around you at speed and you could feel every ripple in the wave. The neutral bouyancy thing didn't seem to bother me much at 16. [/i]
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Post by Marky V »

Hi Shelfbreak
I seem to have missed this thread, so sorry it has taken so long to reply to it. My balsa sandwich kneeboards have been totally inspired by Bert Berger of Sunova fame, being in oz, he would be my first port of call but from what I gather they are only building boards for pro's at present until the new factory is fully up and running, so don't hold your breath for a few months.
As far as the performance is concerned, I can only judge by my own boards. I have built and ridden 3 kneeboards this way to date and about 10 standups. A sub 6' board comes out at under 6ib easily, so if you like light and lively so far so good! The best bit is that the balsa skins have a much quicker flex return than any other skin material including carbon fibre, so whilst the boards can have any (within reason) amount of flex built in, when they are unloaded they spring back a lot more quickly.
Thw wood skins also mean that they are incredibly hard to ding and so far my first board(1 yr old) whilst not surfed daily, still has no pressure dings at all!
These boards must be glassed under and over the balsa to ensure a proper sandwich, and definately flex better using the lower density eps grades.
Bert obviously has this wired, as he has been building them for abour 15 yrs I think, and whilst there are many of us Swaylockers who have cottened on to this as a fantastic alternative board construction, I don't know of any others who are building kneeboards this way.
Have a look through the swaylocks photo archives, there are a few of my boards on there.
I absolutely love the feel that these boards have and would be happy for anyone who is interested to give them a go. In your case Shelfbreak, distance may be a problem!!!
If I can help any more, thenplease don't hesitate to ask.
Cheers
Mark
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Post by Shelfbreak »

Hi Mark

Thanks for the advice. I'd love to try an EPS balsa sandwich board before I get too old. What I am trying to figure out is how to incorporate a kneeboard shaper into this process so i dont end up with a well made board but with design shortcomings. The recent post from Anal Birth (there's a non de plume that doesn't bear thinking about) on the Gold Coast sounds promising. He manages to get Dave Parkes to finish off an EPS blank before going to a third party for the epoxy etc. I am still waiting to hear from Nev/Bert Burger for a reply to my inquiry but I was advised that they wouldn't be accepting orders for some months yet.

In the meantime I am awaiting a new Flashpoint from Bruce (6' rounded pin thruster), currently really enjoying my newish Blast F2K fish ~5'10" and have a Parkes 4 fin for the beachbreaks. So by the time I sort out a way to get a board made in the 'new ' stuff I will be in a complete dither about what design to go with!

Regards

Anthony
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Post by lowrider »

Hi Anthony,

I've been communicating with 'ChasingLefts' (US based) through Swaylocks...he was interested in the dimensions of my fish.

this sounds interesting, if a little hard to picture...

"Steve Forstall is making me a eps/syntex/epoxy quad fish at 4'8x23x2.25 with a concave deck and bottom channels to achieve the venturi effect. hopefully it will go real well...."

cheers,
Andy
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Post by analbirth »

Coming into this thread late, but.. I've been making EPS stringerless carbon kneeboards for a few years now, or should i say puting together with the help of dave parkes [ shaping the blank ]
Peter Mo [ carbon & f/glass laminating ] & I'm doing the running around.
I get the eps blanks from a local set design mob, they plot the rocker top & bottom & plan of an old board into the computer, hot wire a new blank, shape it & glass it, easy. I love em. light & they surf light as well, they can be a bit corky if you dont take some extra thickness out, duck dive great just pop out the back. I've got 2 quad fish's a 5'9'' & a 5'11'
There not bullet proof but for a board with a blank that has no strength at all
the carbon/glass combo is quite good. the 5'11 is 4 years old and the best board i've ever had [ shape ] but i had the exact shape in a poly/glass board & chalk & cheese had to sell it. Going away for 2 weeks but will get my finger out & post some pics when i get back. Cheers AB
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Post by KAVA »

ANYUONE KNOW IF SURFTECH WILL HAVE A KNEEBOARD DESIGN? I WAS CHECKIN THE SURFBOARDS OUT WITH WANDERER WHEN HE WAS IN TOWN (AT FROGHOUSE). any Idea if there will be a kneeboard design? they are seriously light and durrable!
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Re: pe?

Post by Rob »

skansand wrote:i PRESUME YOU MEAN PU (POLYURATHANE) NOT PE (POLYETHYLENE) THAT WOULD BE BODYBOARD MATERIAL......HMMM PE KB's I WONDER...
Yes, doable, been there, done that, but used Arcel as the core material instead of PE (Arcel is a mold blown blend of PE and PS - PS adds a great amount of stiffness and durability to PE) ... these boards are fully heat welded - no glues are used.

Image

Image

http://mjwcustoms.com/hybridz/

Riding a Hybridz in some decent juice ...

http://mjwcustoms.com/hybridz/p2.avi

http://mjwcustoms.com/hybridz/p3.avi

All these soft kneelos sport internal carbon fiber tube stringer(s).

I like the concept of a hollow wood kneeboard, but few folks can build such complex beasties. However, I think that EPS/RR epoxy boards are within the crafting reach of most folks, and that's the direction I'm into these dayze.
Last edited by Rob on Mon Aug 14, 2006 8:34 am, edited 1 time in total.
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Post by boards_and_fins »

KAVA wrote:ANYUONE KNOW IF SURFTECH WILL HAVE A KNEEBOARD DESIGN? I WAS CHECKIN THE SURFBOARDS OUT WITH WANDERER WHEN HE WAS IN TOWN (AT FROGHOUSE). any Idea if there will be a kneeboard design? they are seriously light and durrable!
I hope not. With EPS/Exoxy you can get a custom board that is basically as durable. With Surftech you get what Randy French's marketing people think you should ride. Plus I cant even imagine riding a Surftech kneeboard. I have ridden the DOC HVP standup model and if there was any chop watch out. Its like riding a boat hull.
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Post by K-man »

What B&F says is on the money.From what I've seen and felt,The boards are way too light[corky]For my style of surfing.Plus there's really no $$$$$ in KBs,since Economics are partially driving the market,there's no incentive.

The shapes of course are one of the determining factors,and unless someone builds a''world class'' KB.s out of these materials,I don't see a whole lot of attention coming from the 5,ooo + members of the KB clan.

I could be wrong....Maybe a few of our underground clansmen will have go at it and produce something worthwhile.Didn't I see an epoxy picklefork KB somewhere on this site?
We're out of touch up here in the boonies :lol: Don't be too harsh at my ramblings.... :wink:
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