Benny
I think that by removing this glass that you will also remove many of the structural qualities of your sandwich, in fact it ceases to be a true sandwich skin. I know what Bert’s reaction would be without asking!!
Good looking board though.
Cheers
Mark
Hola,
About the EPS-glue-DCell-glass-glass option.
Since it’s not a sandwich, I mean 2 layers of fibreglass are not some mm. away from each other, DCell seems not very useful for it’s intended for. Maybe just for denting should it be helpful.
benny !!, marky was right …
a helpful hint …
get each new material you may want to try , bend it , break it , crush it , stretch it , expose it to solvents , water, oils, and so on …
once you get an understanding of exactly what each material can and cant do and you found its strengths and weakneses , then its a matter of combining different materials and placing them in arrangments to make the most of there strengths and minimise there weaknesses …
do test panels , theres no right and wrongs , just differences in results and longterm durability , and of coarse performance …
you guys are gonna freak when you see whats being built into a sandwich now …
full morph control …
would love to post pics , but will have to wait till the plan unfolds …
regards
BERT
Well, I knew it wouldn’t be a true sandwich…really just a different blank, like a Clark with all the density at the outer shell…
Did someone say break tests? I’m compulsive about that sort of thing:
EPS with a balsa sandwich on one side. Check the flexibility of balsa & epoxy
This one’s the piece of d-cell sandwich that came off my finbox installation router cut. Check out how much EPS pulled up with it. I had to use a pry bar to detach the piece, even after routing all the way around.
Here’s an old one from where I used d-cell with gorilla glue as a triple stringer setup. When I templated the board, I got pieces from the outside stringers, which I tried to break apart. Looks like the gg got serious penetration into the EPS. So much so that I was wondering if a sandwich is (although clearly stronger) always necessary…
Here’s an old one from where I used d-cell with gorilla glue as a triple stringer setup. When I templated the board, I got pieces from the outside stringers, which I tried to break apart. Looks like the gg got serious penetration into the EPS. So much so that I was wondering if a sandwich is (although clearly stronger) always necessary…
necessary, no, but based on Bert’s comment that by putting the glass in (thus making the sandwich) you can actually reduce weight (less resin/adhesive) and get more strength. So that is the path I am going. Just got to order some 1-2oz glass for my interiors. First project will be 6oz inside and out just because I have an entire roll of 6oz.
i just thought i would pull this one up , save the lurkers having to dig around for it …
the last time i saw this thread it had 10,000 views …
what the hell??
swayology , the new career in surfing …
does it pay tho ??
$50 .00 , send cheques or money orders to …
o , i thought i was roy for a minute , trying to get 50 bucks for a diagram …
i was lurking at surfer (yes lurking is fun ), sounds like roy is bummed at me , maybe i set a new value for information , cut roy out of his margins …
sorry dude , just having a little fun …
will drop by one day …
regards
BERT
G’day Bert,
Glad you bumped this post up, cause I was looking at that corecell board you made and I want to know did the corecell change colour after a few months sun exposure? as a few years ago I nailed a piece by itself (no glass on it)to a post outside and it went pinky brown after about 6 months (over summer).
Mike
What about these blanks?. They seem to be machine cut from the same block…
Was thinking this might be a good one to bring back to the top again. Thanks Bert!!!
This thread is like one of those books that you keep reading again and again and each time you discover new meanings to what you thought you understood.
Rio
THIS is the future. Nobody can say ‘I didn’t know’…
What a treasure this thread is!! I always wondered about this technique, and here’s a good start on it.
I’ve been wondering about aircraft grade plywood as a veneer (well, originally a fin-) material instead of balsa–
aircraft grade birch plywood is available in insanely-thin stock, with multiple perfect (absolutely insanely thin) plies, near-absolute uniformity, even better strength and perfect tuneability… the varied direction and density of the grain is canceled by the extremely thin plies
I guess there are properties to each that the other wouldn’t have, and I suppose one might be AGP being vulnerability to delam’ing itself, but the stuff is ultra quality and super tough. I’ve got a boomerang made of it that has the finish worn completely off the bottom and I’ve gotten it wet in dewy grass and not even a hint of dl
I could see where the bonds between the plies might also act as barriers against penetration past one layer, preserving liveliness
My 'rang is 3.5mm thick, 7 plies, and they make much much thinner stock with absolutely micro plies
In thinner stock, it seems like the best possible wood veneer material for vac bagging…
Hello guys,
I’d just like to say that this place is awesome! I started reading here because I wanted to build a fiberglass/foam skimboard, and now look what I’m getting into. I read most of this thread, there is a ton of good info here. As a little contribution to this forum and you guys, I’d like to offer to get updates from the RC airplane world, where vacuum bagging and composites are the biggest thing since lithium batteries hit the electric market (Sorry guys, I’ll make it simple. Regular batteries=heavy=bad, Lithium=light=good). We are using Carbon Fiber, foams and glassing like never before, although balsa is still dominant in the overall picture, in the electric airplane world, the new composites are taking hold fast. My current plane is extruded (I think) foam called depron, you can see it here http://www.depronusa.com. It’s used in Europe as an underlayment for siding etc. It is very stiff once braced with carbon fiber, but in a sandwitch construction, it would make a good skin material I would think, and under fiberglass it would be practically indestructable. It does not rebound though, that is something to keep in mind. I’m using a similar foam on my first board, now that I see many are using EPS (Syro type foam, beads) that is a little more springy, I will use it for future projects. Besides, it’s cheaper. What I’m using is similar to the blue and pink foams you can get a home depot. I’ll check the composites fabrication forums at the RC site I frequent and keep you updated! Oh yeah, I’m hoping to go to Cal Poly San Luis, how’s the surf there? lol.
Thanks,
Nathan
Nathan_P,
Lots of good surf within short drive time of S.L.O., both north and south. Good luck at Cal Poly, great school. A good friend, and surfing pioneer, Alan Nelson, (Waimea 1957) did a vac bag Birch ply skinned board in 2001/2002 or thereabouts, and told me it was insanely tough and near impossible to ding.
Aircraft grade birch plywood. Lemme see if I can find a link so the fellows can peruse/pursue…
Ok. http://www.superiorbalsa.com/
These guys seem to have it ALL covered pretty darn well. Check out their price guide in HTML
Ooohhhh, what’s this…hello Mr Hess, nice boards!! Nice skins! http://www.hesssurfboards.com/pacheco_quad.html
This thread is pretty much everything you could ever need to know about sandwitch construction. It’s awesome. I wish I’d known about it earlier. I noticed there was talk about the RC glider community. That’s where I found out about vacuum forming. I actually got my first blocks of EPS foam from a glider wing manufacturer called Flying Foam, in Corona. It was great to see Bert Burger’s thread. It made me feel sort of validated to see someone with his experience and expertise doing the same thing as me. And for so long. This is my first post, so hi everyone. It good to finally be aboard.
Hi Jeff
welcome to the world of fun with eps and plastic bags
Mike
I did a few test boards with that aircraft grade birch ply a while ago and I turned away from it for a few reasons. Although it is called light ply It weighs a bit more than other materials that I used. It is pretty rigid and brittle, so it is hard to form around those compound curves and can make a board have very little, if any, flex. It is also very expensive. I did like its impact stength. felt impenatrable when used in a sandwich style construction.
Hey, wow, Daniel, what thickness did you use? I was thinking about the really thin stuff. And did you use anything to enhance the flex for shaping? I need to go look up this stuff that supposedly plasticizes wood temporarily for shaping— do you know anything about that?
I would have thought the flex could be engineered by using thinner ply and less glass, but if you’re doving sheet panels of 1/8" into the rails or butting them against them and using stiff rails, and then wrapping it all in very much epoxy and fiberglass or carbon cloth, I could see how that would eliminate a lot of shear/flex. I would think they would then need a gap near the rails to float the panels and allow shear, but if you’re only using the EPS for spine and ribs, your rails and skin are the suspension/the major load-bearing components
Speaking of, have you ever had a fin gash in one of your rails? I saw some cork lam rails suffer something frightening here a week or so ago.
good to hear from you!
Just Thought I’d add my current craze to the wonderful stuff here.
I’m Resin infusing my next board.
Shape the blank, use VERY little contact adhesive spray to hold ALL layers of glass in place, cover it in peelply and mesh, pop the whole thing in a bag, suck the air out, open a valve and let the resin flow in. Whole thing done in one shot. Remove peelply and apply glosscoat. Using epoxy and slow hardener.
Is it the way of the future? Works great for boats and wind turbine blades, why not boards.
Will post some shots of the build as it goes.