Tuesday, July 24, 2012

Building A Canoe: Steps II, III, and IV

After making the sawhorses, the next step was making the strips. I decided to make my canoe out of basswood and walnut because for some reason, I can't say why, I wanted as much of a dramatic contrast as I could get. I had thought about staining white cedar black but with all the sanding and shaping that is needed once it is together, I realized I would have to restain it after the assembly which wouldn't likely look too good because of the difficulty in getting the stain lines to be precise.

I had never worked with basswood before but it is known to be easy to work and it is light in color and weight. It isn't rot resistant like cedar but with all the epoxy and varnish, I didn't think it was really an issue. I also was concerned about the possibility that basswood and walnut would shrink and swell at significantly different rates but I checked and, though they aren't the same, they are in the same ball park. Again, with all the epoxy and varnish, I didn't think the changes would be significant. 

I've worked with walnut a lot and know it is also easy to work and relatively light, although I was surprised at how much more dense it is than basswood since I'm usually comparing it to maple or ash. I had notice basswood was mentioned as a wood choice in the Gilpatrick book but I had never heard of anyone building a canoe with walnut but I figured that was probably because of the cost. Objectively, it does seem like a crazy wood to chose but I'm not looking for a sane canoe, just one I'd like to look at.

In reality, the cost of the lumber is a real small part of the whole project, even with the walnut. Basswood is ridiculously cheap. I bought 28 board feet for $25.20. The walnut is of course much more expensive. The lumber yard was selling it for around $7.50/bd-ft but I figured I had enough older stock which I had bought for around $6.00/bd-ft so I didn't get any more (hopefully the price comes down before I need more) I didn't do an actual count of how much walnut I'm using but I'm sure the cost is under $30 (in comparison, the fiberglass and epoxy will cost around $600). To my surprise though, when I started milling the walnut I had, I found I had some exceptionally figured pieces. I actually would have preferred that it was straight grained because it would be easier to work but, hopefully, the curl will show through all the fiberglass. 

Once I had the lumber I spend a two or three days dimensioning it and then cutting the strips and milling them with cove and flute edges so the fit together tightly around the canoe forms. One of my goals in dimensioning was to get a variety of widths between 3/4" and 1". Luckily, I was able to get three sizes, 3/4", 7/8", and 15/16". Since my shop is pretty tight, I couldn't work with lumber larger than 9' so for the basswood my strips are either 4', 6', or 9'. With the walnut my strips are much smaller with the longest being 5'.

Based on the information in the Gilpatrick book, I thought I needed between 1400 and 1600 linear feet of strips. When I had finished I was a little short, only 1385 but given that my widths are greater than what he was using I hoped I'd be okay (after finishing about 1/3 of the canoe I've done another count and I'm sure I have plenty).
1385 linear feet of bead and flute strips
Normally the next step would be to build the strongback and canoe forms but I was lucky in having a friend of a friend lend them to me. Given that I don't foresee building another canoe, building the strongback is a lot of work for something that I don't even know where I'd store it when I'm done. Having the forms already made was also real helpful because the Gilchrist book doesn't provide clear dimensions and pulling the measurements off the drawings is difficult. 

As a side note, I think it is worth mentioning the size of the sawhorses again because I couldn't find any recommendation as to how high they should be. I ended up adding a couple of inches to bring them to 27". I'm 6'1" and I think that is a good height for me, make adjustments accordingly. The good thing about the two inch spacer is that I can easily remove them if I find that they are too high when I'm working on the bottom.
After I installed the first strip I walked away from the project for five days in fear that I wouldn't be able to do what I was envisioning. Until you start, it is difficult to understand how much the wood has to bend and I wasn't sure how I was going to attach small sections of strips, especially of the stiffer walnut, and get it to glue tight. That second row is a killer because it is the point of no return where you start gluing. 
After five days I worked up the nerve, bring all the clamps and fastening devices I could think I might be able to use. After the fact, I realize I should have flipped the strips so that the flute side was facing up. With the cove side facing up (as I did it) I risked damaging the edges as I clamped them between the forms. I would have re-done the first row because of it but I was nervous that I didn't have enough strips and didn't want to waste any. 
I quickly realized that staples would not work for holding the strips because the walnut was too hard -- the staples would just bounce off. So I ended up pre-drilling holes and attaching them with drywall screws. Unfortunately, this meant that the forms would be shot by the time I was done. I should have just made copies of them before starting so I wouldn't damage the borrowed ones but then I figured I'll just copy them when I'm done so the lender can get a new set.
I have been going with a random width, random length design. I don't want the finished piece to be at all visually predictable. Along with the dramatic contrast, I think it will be visually very interesting. Another feature that I'm planning on is to use different size walnut and maple dowels to fill all the drywall screw and staple holes (contrasting with the color of wood the hole is made). In addition to adding another layer of interest to the piece, I think it will give it a rougher look, which is important given that so much of it is made with walnut -- I don't want it to look too precious, I want it to look like it doesn't matter if it runs into rock and gets a dent.
In this last image you can see that I added one strip of cherry in the middle lower section. I really wanted one piece to be different than everything else and cherry is a nice intermediate color. Incidentally, this canoe would have been easier (and cheaper) to make with cherry instead of walnut. To my surprise, cherry is much easier to staple than walnut.
As I'm going along, I'm more pleased with how it is coming out. It is slow going though. With all the choices to make -- width, length, type of wood, avoiding lining up the joints, how to clamp or attach section, along with all the time needed to step back and admire the progress, along with the extra time needed to daydream -- it is taking me about 45 minutes per row per side. To give myself a mental break, every now and then I add an all basswood row, they are so much easier to install.