Sunday, September 13, 2009

Making patterns and parts

Once the lofting was done, I started making patterns for all the frames. For most of the patterns I used eighth-inch plywood. Two of them were a special case and I made them out of quarter-inch ply.

Five of the frames are made out of plywood and two are made of oak. For the plywood frames I used three-eighth-inch marine plywood made in France to BS 1088 standards. It's really good stuff and you pay for it at about $90 for a 4-by-8 sheet. Luckily, I was able to get all five frames out of one sheet.

The oak frames I made from some wonderful white oak I've been air drying for about 10 years. It's hard, tough and heavy but works well with hand tools. The frames are double sawn, which means the frame is put together in sections (futtocks) and doubled so as the grain runs out on one side it is reinforced by the other side and all joints are over staggered on the other half of the frame. It's easy to show someone what a double-sawn frame is, but hard to explain.

Because these were made from oak I used Weldwood Resorcinol plastic resin glue instead of epoxy. For some reason epoxy doesn't work well on Oak, but glues well with Resorcinol. I put wax paper on my woodworking bench and glued the futtocks together on the bench top to keep them flat. I used my biscuit joiner to make sure the butt joints were tight. Using this method I basically made two frames, then glued them together so the joints were staggered. (Maybe you can get the idea better from the pictures.) One difficult thing about using Resorcinol is that it has a narrow working temperature and doesn't cure well in temperatures below 68 degrees F. Since it was getting into fall, I made a tent out of an old plastic shower curtain and put a small, thermostatically-controlled heater in it so the glue would cure.

I have to say that the oak frames were fun to make and impressive when I finished with them. They look real good in the boat too. Any friend who came to visit had to make a trip to the shop to see the frames.

Next, I made the inner stems for the bow and stern. The plan called for them to be pieced together, but I wanted to laminate them because they would be lighter, stronger and have a cleaner appearance. I lofted a pattern for the bow and the stern. (You would think since Valgerda is a double ender they might be the same, but no such luck.) Then I built a bending form. I sawed up more of my white oak into quarter-inch thick strips two-inches wide, painted Resorcinol on both sides and clamped them to the form. I used about 40 of my largest C clamps and all of my F clamps to do the job. Then, since winter had arrived, I hauled it all into the house for 24 hours so it would cure. It was heavy and awkward to get it in the house. Luckily, I didn't get glue anywhere in the house and Resorcinol doesn't smell too bad.

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