I was wondering if anybody has tried a balsa sandwich-like construction (maybe even just for the deck) without vacuum bagging, and if you think it’s even possible.
Also (unrelated), I was thinking about perimeter stringers and flex patterns and all that, And I thought: What about carbon fiber on the rails? as far as I know carbon fiber is much stiffer (and springier) than fiberglass.
If I have a stringerless EPS board, and I glass a couple of strips of Carbon fiber on the rails, would it be like having perimeter stringers, and make the rails stronger too?
That’s right. Wasn’t even a pump failure, unless not existing is a failure
I wet out the glass, laid on the balsa, and put 30 1-gallon ziplock bags full of warm water all over the board. A few clamps & blocks near the edges. Its not quite like the 33 psi you get with vacuum, but it worked. The board is over a year old and still going strong…
Let’s see, if the average width is around 20", length is 120", I have 2400 sq in. Water weighs about 8.5 lb/gallon, so 30 bags is 255 lb. Looks like .1 psi is enough to stick balsa on a blank (with enough resin & 6 oz glass…).
Something I tried a number of years ago for a snowboard was to build a press. Basically it consisted of a bottom rocker table and a framed deck rocker made from plywood. 2x4s where placed across the two sheets and clamped down with lag bolts. Much the same as Benny1 did at the nose of his board. Care must be exercised in clamping since you can get more pressure than the foam will support.
While the above method will work, bagging is more practical and you are not left with a press sitting around your garage that is really only good for another board with a similar rocker.
Whatever you try it will probably work and you will gain some knowledge to share. Good luck.
I did a balsa deck without vacuum. my procedure is described in the archives somewhere. it wasn’t too difficult. search my user posts… there aren’t that many. basically I used elmers glue and blue tape to secure 1/16 ‘’ thick balsa sheets. It took to the compound curves pretty well. the deck even has a bit of concave. I need to post a picture but I’m still confused about how that works… not very techno savvy. the board is pretty flexy and super strong–3x6 oz over the balsa. lowes eps. no stringer. been surfing it for about 10 mos. now and its going strong.
Yeah, vacuum isn’t a necesity, unless you want 100% sure bonding, and the least amount of resin weight…
My kiteboards with Luan and weights have not delammed.
As for the carbon… carbon laminated is very stiff, is NOT memory flexible!
Once the material is compromised, with flex or impact, it delams instantly from the foam and NEVER goes back to it’s original composition or shape. It might not break right there, but surely will at some adjoining location, usually somewhere between stiff and flexible.
If you go 100% carbon, it’s almost a sure thing it rides too stiff, and will break at the sight of a hollow wave.
that’s exactly what I had in mind: a stringerless board is (I assume) not stiff enough, and hearing about how stiff carbon fiber is, and perimeter rails, I thought why not lay down carbon fiber strips on the rails, and get stronger rails and added stiffness along the perimeter?
About the “press” that you mention, could it be an evolution of the adjustable rocker table that many here mention?
Adjustable bottom/rocker, adjustable deck rocker, one press for every board. Sounds like even to just use the bagging technique you need a rocker table no matter what, therefore…
When I look at Benny’s zip lock set up I wonder what happens where the bags aren’t touching? Do you get hollow spots (delams)? Could you put the zip locks everywhere and then about when the epoxy is starting to kick (getting really sticky) roll the entire surface with a one of those metal laminating rollers? And then just nurse it for a half hour or so rolling it?
Howzit lilibel, I’m thinking huge trash bags ( 55 gal ) full of sand might work and you would have less gaps and they could hang over the rails also.Aloha,Kokua
I agree with Kokua that sand would be better than ziploc water bags. I was going to do that, but I only made my kids’ sandbox 8’ square, and this is a 10’ board I’ve also done lots of ding repairs with ziplocs full of sand, its less wiggly than water, so you can lay a bag over a rail & balance it better; it weighs almost as much.
I did have a couple things going for me. One, the warm water helped kick the epoxy into gear. (Sand that had been warmed by the sun would be good for that too.) I used balsa strips on that board which were almost 1/4" thick, because it was my first one and also because I wanted the extra strength on 1# EPS for a 10’ longboard. Also 6 oz glass top & bottom, which all added up to overkill. The 1/4" balsa laid flat enough between bags, but you might get air bubbles between bags with 1/8 or 1/16" balsa, but I don’t really see how it would want to lift up in those areas. I think you’d hit it with the roller first, not afterwards, to get good adhesion and then lay out all the bags. It will be fine. Even with my overbuilding, its no heavier than a classic foam/volan PuPe.
Benny, that’s a real beauty. R U telling me that it al was done without bagging?
Let me see if I get it straight: “glue” on the top and bottom veneer with the water bags, then glue the rails in place? (balsa rails? do you start with balsa strips and glue them curved in layer, and then sand of the excess?)
The method I used would be a step backwards in evolution. The press was not adjustable. I suppose if one was to make one now it would make more sense to build it with adjustments. A bit like big rocker sticks. Actually the water and sand methods sound the most reasonable.
Yes, just like you said. Each rail got 4 pieces of 1/4" balsa, bent & glued on, then shaped like any rail. Then glass over the whole works.
At the time, I couldn’t get my head around adding & shaping the rail wood before putting the deck on, so I also put balsa in the rails & planed it to bottom & deck thickness before the skins, so the edges of the skins would be supported by more than just foam. Ended up with more than 2" of balsa on the rails, at the widepoint. I don’t do that anymore. And I do use a bag now.
I’ve also done lots of ding repairs with ziplocs full of sand, its less wiggly than water, so you can lay a bag over a rail & balance it better; it weighs almost as much.