Re: [KKSurf] Balsa Fish Project

Here's what I did to grab rockers for my hotwire templates, it worked perfectly, just hope it translates well to text... Should have taken a picture...

1. Get a chunk of masonite as long as the board and wide enough to take the whole rocker, screw it to the side of a workbench so the straight edge is flush with the tabletop. The smooth surface of the masonite will be perpendicular to the floor and tabletop.

2. Lay your board on top of the workbench in such a way that the stringer is directly above and aligned with the masonite edge. Your board will be half off of the table, so you'll have to weight one side of it to keep it from falling off. Looking at it from the side, you should see your board's profile, and below it a long flat expanse of masonite (hopefully the smooth side).

3. Get a painter's mixing stick from homedepot and cut one end into a point. drill a hole some distance from the point (probably an inch more than your nose rocker measurement) and jam a sharpie (or other fine tip permanent marker) into it so the tip protrudes through the stick just a little.

4. Press the stir stick flat against the masonite with the sharpie tip against the surface, and the pointed end of the stir stick at the tip of your board. If you're set up right, this point should be right against the stringer.

5. VERY carefully, move stick/sharpie jig along the stringer to the tail. by making a mark a set distance from the bottom of the board, you are effectively duplicating the rocker. The stick HAS to stay vertical as you make this mark, or you'll wind up with poor duplication. Really the only way to screw it up at this point is to move your stick off of vertical as you make this mark. You could even go over it twice to make sure you got it right.

Now you have your bottom rocker profile.

If you are just looking to get a rocker profile to reproduce that board's bottom, all you do at this point is cut on the line, sand smooth and viola!

If, like me, you want full (top/bottom) rocker profiles for hotwire cutting, read on...

6. Flip over your masonite so the your drawn rocker "bottom" is facing up, and again align it with the workbench surface.

7. flip over your board, this time bottom up, align stringer, weight it. You'll need to do some careful measuring and height adjusting to get the board aligned with the already-drawn rocker curve. As long as your nose and tail points (measured from the BOTTOM of the board to the line) are the same distance from the rocker line, you're set. its not easy to balance a board on the tip of its nose and tail right on the edge of a tabletop, but with lots of stuff piled underneath, it can be done. This is probably the touchiest part of the process.

8. Measure the distance from the deck at the thickest part of your board to the drawn rocker line. Add to that number the thickness of your board (use calipers, shapers sometimes make mistakes on written measurements). This number you get is the length you need to make your drawing stick from the sharpened tip to the tip of the sharpie marker. I found it easier to get the sharpie set in the stir stick, then whittle down the point until the measurement was right.

9. Again draw along the stringer with your stick/sharpie jig, keeping it perfectly vertical. If your setup was careful and correct, you'll be staring at the drawing of your perfectly duplicated rocker profile.

10. if you're doing hotwire rocker profiles, put another chunk of masonite under this one, and drill regular holes along the template, bolting them together as you go along with 1/8 machine screws. More bolts are needed at the ends where the templates are thinner and more flexible.

11. cut both layers with a jigsaw outside of the marked lines, and sand down to just almost meet the line. Eyeball frequently to take out any wobbles induced by the templating process.


Sorry, I got a bit off track on this, but I've been meaning to post up that method for a while. It is a bit tedious, and very "garage", but necessity was the mother of invention on this one, and it does work extremely well when done with patience and care.