balsa orientation and placement

To DanB, Silly and anyone else doing the new angled balsa pattern…


you indicated that the angled pattern gives you incredile longitudinal flex versus the standard parallel pattern.

I see Bert putting it on the bottom tail section as well as CMP which would make these area flex more.

Silly and you have decided to play the pattern along the whole bottom and Silly did it to the tail section of the deck which I presume would be to give it more snap…

So my question is…

do you stiffen the deck(parallel) and make the entire bottom soft(angled)?

do you just make the tail soft(angled top and bottom)?

what’s the effect of doing it the to side panels of the deck with a parallel strip down the middle like silly’s new blue balsa?

And I presume none of this will work properly if you aren’t using rail bands and wrapping the balsa over the rails like I do… Seems like I would the completely opposite effect wrapping angled balsa over the rail somehow…

Thats exactly what I did. I think that its important to have the bottom be flexible in order to let the other parts of the board do its job (although I don’t have any numbers to support this). However, I originally choose to angle the whole bottom because it looked nice. The deck what thickened in the middle so that it would provide a little more impact resistance, but I don’t think that I’ll do it next time. On the deck I tried to wrap the angled balsa over the rails and it was a mess. I won’t be going this way next time.

Here’s what I’m trying next (probably sometime after Xmas( this could change)). Angled balsa bottom and rails done with light glass and flexy epoxy. The deck will be done with 1/8th corecel for impact resistance, ease of rail blending, and the ability to add graphics. I will do the horizontal stringer exactly the same (even though I should probably try to move it to the neutral axis). The shape will be the same as my previous one (maybe a little less wide since sometimes it feels like I’m sitting on a bucking bull). This will introduce three new variables (which is too many at once but I don’t have the time or money to change one thing at a time).


I angled the balsa on the tail area of the deck on my last kneeboard, loads more flex than previous boards. When the board is on the shaping stands, If you hold the board to the stand (bottom up) with one hand, you can move the tail up and down with the other. Iknow this probably isn’t technical enough for many out there but I can’t do it with any other board I have made!

As for the ride, I can’t feel the flex in the water, I built the board for bigger (for me) waves than my previous efforts and it feels good and solid in over head waves, being longer (6’2") turns are more drawn out than I am used to, so I need to ride it more in bigger waves to understand more of what is going on.

The deck concave is really extreme, and the main feedback from kneelo’s is concern that the scoop will stop you being able to place your knees far enough apart ( on the apex of the rail), I don’t think its an issue . The concave deck’s are just so nice to lie on when paddling and to duck dive.

I really like that first shot! Thats one high tech looking board. I should add that you did a great job blending that diaganol balsa onto the rails. Your finish work is excellent!

Kia Ora oneula

I think that the board bottom has more GIVE from the balsa that way but it could be other factors

ie balsa density.

i like the way it looks as well

( i assume it is to make a more flexible bottom .and this appear to be the case as the blank was pretty flacid until i put on the top skin)

however I wont be doing on the deck next time because it didnt wrap the rails proprerly and left some unsightly bumps.or if i do do it ill preglue the sheet and sand down the balsa a bit where i want it to wrap the rails

maybe i didnt pull enough vacuum is also a possibilty

I will be doing all bottoms this way from now on

I dont wrap all the way but leave a flat edge when i shape the board , that way i get an even line along the rail. then i shape the rail finally after the top skin is on.

Marke your work is unreal. beautifully finished.

im glad my camera is low res so you cant see my mistakes

are you doing a 2 pac?

i tried it with a sponge ,sanding between coats and im pretty happy with it


however I wont be doing on the deck next time because it didnt wrap the rails proprerly and left some unsightly bumps

At least I’m not alone! I was able to sand them out but the appearance took a major hit.

I think this balsa orientation question is a good one and can’t wait to hear what some others think. I was planning on gluing up my first balsa this weekend (unless Wilma has something to say about it) and I am still undecided on the orientation.

Personally, I thought for the deck, the angled layout was for better transferr of foot pressure out to the rails, not neccesarily for better longitudinal flex. But I do see your point.

Doing the angled pattern on the bottom doesn’t seem to make as much sense to me. I would think you want the bottom to have flex in a variety of directions, not just longitudinally. And that would be best achieved by using thinner balsa, not angling the orientation. Plus you get the added benefit of less weight.

I would recommend keeping it simple for the first one. Its getting easy for me to put the pieces together now, but the first ones were filled with all kinds of drama!