Today I made the stem molds. This was the first time I’ve gotten to turn points on paper into a three dimensional object made of wood. The plans that I’d lofted earlier get taped to a scrap board (to save the workbench from holes and cuts). A tiny finishing nail is driven through each point I’d plotted earlier. I ripped a thin piece of cedar about 1mm thick to use as a fairing batten. By holding the batten against the nails I can then trace a fair curve that the points describe.
After carefully cutting with a razor knife along the curve produced by the batten a template of the stem mold is made. I left excess paper on the other side of the centre line and cut viewing windows as Canoecraft suggests. The stem molds don’t get flipped like the station molds so it’s not as crucial here, but it was very easy to line up to the factory cut edge of the plywood this way. I think it’s worthwhile doing.
You can see I’ve got two sheets of plywood on top of each other there. After tracing the template I lined up the factory cut edges of the plywood. I used my jointer plane on its side to align the sheets and keep them flush until they were clamped.
To keep them together while being cut out, I put four brad nails into the molds. You want to make sure that your brads are far enough back from the edges that you won’t risk hitting them while cutting the outline or drilling the clamp holes later. The first one sunk in too deep into the soft birch plywood. For the others I used a thin strip of wood left over from making battens and put it on top and nailed through that. Then I could just tear away the sacrificial strip and leave the head standing proud a bit which made them easy to remove at the end.
I cut the area with the station molds off from the rest of the plywood with the skillsaw to make it easier to handle while cutting out. I started out trying to use the little bandsaw in the shop, but the blade was too wide and dull to do the job. Canoecraft says to use a reciprocating saw as a second choice, and claims a jigsaw is a poor choice. I have always had results to the contrary so I went to the hardware store and got a brand new blade for the jigsaw and did a test cut on some of the waste ply. The results were quite good and the cut was square so I proceeded to use that to cut out the molds. I’ll use it for the rest of the station molds as well most likely.
Once they were cut out I put them on end in the tail vise and used my block plane to trim it right to the line and knock off any slight high spots. After checking for square along the whole length of the edge I used a sanding block to touch the edges and remove any splinters that plywood always develops.
I used my marking gauge to scribe a boundary line 3/4″ from the edge and then laid out the spacing for the clamp holes. Canoecraft recommends 4″ centres so that’s what I went with. I drilled tiny 1mm pilot holes and then switched to the 2″ hole saw. By having the two sheets of plywood joined together you can use the hole saw from both sides to prevent blowout. Cutting down through the first sheet (stopping often to remove the sawdust and keep the saw cool) and removing the plug, I then cut down through the bottom sheet until the pilot drill poked through. After doing that to all the holes on one side, I flipped the mold and finished off each hole from the other side.
I would have loved to have a 2″ forstner bit for the clamp holes. Using one of those in the drill press would have made the process take a quarter of the time.
After pulling the brad nails out, what you’re left with is two identical stem molds. Obviously if the canoe being built isn’t symmetrical then you would need to do each mold individually. My huron cruiser is symmetrical so other than the centre mold (#0), I’ll be able to do all the station molds this way as well.
The next step is to prepare the strips to bend and form the stems themselves. I found a nice piece of cedar and had enough time left today to make up the three strips for one of the inner stems. The stems are 7/8″ wide and made of three pieces 1/4″ thick each. Because they will be steam bent in a fairly extreme curve a straight grain and no knots are required. Though Canoecraft doesn’t say to do it, I gave each strip a pass with the block plane to make them absolutely smooth where they’ll be glued together after bending. I also took a few more shavings off one end of each of the strips to give them a bit of a taper. The inner stem will be present inside the canoe when it’s finished and I’d like to have mine taper down into the planking so it isn’t so abrupt.
I made sure to keep the strips oriented the same way they were before they were cut so the grain is consistent for ease of working later. I laid them in order on top of each other and taped them into a bundle with masking tape until I’m ready to bend them. I’ll do the same for the other inner stem and the two outer stems. The outer stems will be out of a harder wood to take the abuse, I just haven’t decided what yet.
