2006 Mair Surfboards 12' 0" x 9 3/4" x 22 1/2" x 9" x 3 5/8" The Hanalei Spear

This is a hollow balsa gun that I shaped for Felipe Pomar to ride large Hanalei. It was shaped from a hollow balsa blank which is different than a chambered blank. The blank is made from sheets of balsa on the top and bottom with strips bent around the edges for the rails, the strings set the rocker and profile.

Was a really fun board to shape. It is glassed with a 4 oz. bottom and a 6 oz. deck with a 9 1/2" glassed on fin!

Something about a board like this that really touches you, there is some magic in that wood.

Comments

Incredible board.
would love some construction details... thickness of sheets for deck & bottom? internal rib structure? any particular difficulties you worked through?

great stuff.
thanks for posting it.

Aloha Keith:

The construction does not really use any ribs, instead the deck an bottom plates are bent and glued to the stringers [there are two] and then the rail bands are bent and glued to the plates. So the stringers set the rocker.

The deck starts out at 3/4" thick and the bottom at 1/2", these are intended to be shaped down by about a 1/4", in order to get the weight down. The rail bands, or which there are four per side, are 3/4" thick for a total of 3". The effect of these rails bands is that it does somewhat limit how much roll you can put in the deck as you have to be careful when cutting the rail bands that you do not cut beyond the available deck thickness.

The thing I really like about the rail band idea is that when shaping the rails the wood grain is more consistent as it flows in the outline of the board as opposed to running out along the plan shape. This allowed for a much more accurate shaping of the rails.

The only difficulties were ones that are always present when shaping balsa, the main one being you want to have nice sharp hand tools in a lot of different styles. I use a few different low angle and skew angle planers and did very little machine work other than initial banding and outline with a planer. Instead preferring to have nice long shaving from a hand planer!

The main trick I have developed is the outlining process which is a lengthy one to get accurate. I cut out the outline with a jig saw and then I have a portable Porter-Cable drum sander that I use freehand to dial in the outline. This tool does a really good job as it is an oscillating sander and it is fairly easy to sand right to the line. It also ensures that the rail is totally square. I finish off the rails with a belt sander.

I did also use a belt sander a little on the plates to clean things up.

Of course the other trick with balsa is to always sand with the grain. I also feel it is really important to hot coat the bare wood before laminating it as this minimizes the potential risk of getting any crystallization should there be a little moisture in the wood. I also use this to knock down some of the furring that occurs when you sand balsa.

Hope this helps!

I will be posting more photos of balsa boards over the coming months as I have nine more of them that I will be shaping. These are going to range from 12' 6" guns down to a 9' 1" longboard.

- Robin

Drooling. No need to add anything...

These surfboards has been around for quite some time. We need this kind of stuff to be sure of what we are doing. - Aldo Disorbo