And here I'm gluing the spar in. Some small blocks under the spar (hopefully) keep it centered in the blank. I put some weights on to keep the blank straight while gluing.
The blank is initially shaped using a router. Grant used the same method. I've never shaped a rudder before, but I thought it went quite well this way.
The routed blank looks like a mess......
...but is actually not too hard to shape. I put some marker lines in the corner of the routed areas, and then it's easy to sand down. Just keep on sanding until the lines start to fade. I mostly used a surform to do the rough work, and a longboard to finish. In this picture the top half is nearly done. I was surprised how small (thin) the board is; because it's so small it feels like every mm mistake really counts - and it probably does.
End result so far: blank with 'HD' insert (mahagony) at front end. At the whole back of the blank, and the low tip of the blade, the foam is removed and replaced with putty. I also made the HD fill at the back with putty. This is easy to do because of the layer of cloth in the middle of the blank.
The rebate for the uni-directional with the spar in the middle of it make up a big portion of the whole board, and it feels like all the careful (ahem) shaping has been waisted. After glassing I'll check if the profile is still anything near the real thing and if not try to restore it with fairing compound.