surfdabbler

Along the way, I have also started the keel bulb. The keel bulb will be cast from lead. I made a balsa blank in 2 halves, based on the profiles given in the plans. The bottom half was laid into a cardboard box, covered with cling-wrap, and then plaster of paris poured into the mould, carefully prodding and smoothing the plaster to ensure the cling wrap wasn’t trapping bubbles, or pulling away at the sides of the bulb. Once the plaster was dry, the plaster was turned over inside the cardboard walls. A couple of location holes were drilled into the first half-mould, and the 2nd half of the keel-bulb blank was placed on top and pinned into place. Again, cling-wrap was used to cover the balsa. Plaster was poured, and prodded and smoothed to make sure the plaster got into the location holes, and fully surrounded the keel blank.

Once all was dry, the two halves of the mould separated very easily, and the balsa was easy to remove from the plaster. There are a few traces of clingwrap still stuck in wrinkle cracks in the plaster, but on the whole, it is a pretty accurate mould.

I’ve drilled a pour hole in the top, and when I have time, it’s ready for pouring.