It's been awhile....time for filleting

Fillets are put in to fill the spaces between the planks. provide a nice smooth surface for the fiber glass to conform to and glue together the planks. They say it also provides some stress relief by spreading out by providing a gusset-like structure. That might be true for a 4 plank hull, but my boat is 10 planks so the planks meet at a very shallow angle so the fillet is pretty minimal. Here is what it should look like.

You can see the masked area in the bow.

I first masked either side of the seam just even with the wire stitches. Then, I mixed up some epoxy and added wood flour. I mixed in enough wood flour to give a paste consistancy....stiff enough to hold its shape when I made the fillets. Interestingly, the mixture gets thinner over time until it starts to kick and get thicker. I suspect as it heats up it gets thinner until it starts to catalyze. I spread it on with a cut down (narrower) plastic putty knife and smoothed it out with a spoon I got from a thrift store. Note that the stitches are still there. I'll pull them when it sets and touch up the spaces left where the stitches were. I was careful to not get much epoxy on the stitches as it will be hard to pull them out if they are full of hardened epoxy.

Now, for the ugly. The first day I followed other instructions from a major kit maker. They said to mix it up as thick as peanut butter. Maybe that works for them, but I had a real mess. I started with the stern figuring I wouldn't need to look at it if it was a bit ugly.....good thing.

Nothing that sanding won't fix, but it is a but frustrating. The very bow and stern where the planks meet is particularly hard to fillet. I'm sure there must be a clean and neat way to do it...I just didn't figure it out. I didn't work too hard at it, though. It will be enclosed by a floatation tank anyway.

Finishing up the planking

Well, I was sick last weekend and had commitments yesterday, but still managed to finish the planking today. I am pleased that I was able to get the boat fairly straight. I tacked the seams with some "stitches" of hot melt just to keep everything straight until the next time I hit it.

Today, I realized that there are simply going to be a few gaps here and there. Laying out 10 planks, 3 bulkheads and cutting them all out is bound to lead to a few errors and there are a a few spots with 2mm gaps. I started thinking that this would be simpler than doing a strip boat, but I'm not so sure. In engineering-speak, this is an over constrained problem with the shapes of the planks and the shapes of the bulkheads. One is bound to be wrong. I don't think this is a problem with simpler hulls (fewer planks) or with CNC cut planks and bulkheads. By the time I fillet everything (next step), I don't think most people will notice.....well, OK, I will!

I have vacation planned for the next two weekends so I won't be getting much done for awhile. Maybe I'll get some filleting in this week after work.

Cutting and reassembling

I wish I had a decent picture of them on the plywood, but imagine a 14 foot long snake that swallowed a good sized rodent...in other words, long and skinny gently widening in the middle. By varying the shape along the length, you change the eventual cross section of the canoe. The strips are cut out with a jigsaw just shy of the marked line. Then, I used a small plane for the last fraction of an inch. I should have tried to leave something like 1/8". I tried to go closer to the line and sometimes took off too much. I'll end up using a bit more filler or patch in a sliver of wood later. The spring clamps you see (about $1 each from Grizzly) are holding the two pieces of plywood together to minimize vibration and tear out.
This image shows the business end of the jig saw. I taped over the base plate to minimize any scratches on the face of the plywood. You can also see the lay out lines here.
Here you can see the boat with the first four planks out of 10 wired up. I made up a simple jig to drill 1/16" holes 6 inches apart and then match drilled the mating plank to match. You can't drill all the planks with holes 6 inch on center because the planks bend in different ways and you end up with the holes not quite matching from on end to the other.
Here is a picture showing the wire "stitches" holding the planks together and one of the bulkheads. The bulkheads are just there to hold the shape while building the will be removed. You can also see daylight between the left plank and the bulkhead. I needed to adjust the tension on the wire stitches as I added more. I also learned to always twist the wired to the outside. It is much easier especially near the ends.

For each set of holes you need a 4 inch piece of wire. If you do the math, I need to drill 500 1/16" holes (yes, buy extra drill bits) and 250 pieces of wire. I quickly figured out that I needed an easy way to cut the wire. I marked a 4" line at the end of the bench and nailed the wire package to the board....much easier.
Here is a picture of the stern with all the wires. Pretty straight so far. The other end needs a bit of work yet.

Making a 16 ft piece of plywood and layout

The first thing I did was to rip the 4x8 sheets of 4mm marine plywood into (4) 2x8 sheets. I then scarfed the ends with 1:10 bevels with a handplane then epoxied them together with thickened (colloidal silica) epoxy. My bevels were not perfect and the joint is less than great on one piece.

The next step is to layout the strips. My boat has 10 strips: 5 mirror image pairs. The plans I have listed points every foot to define the curve of the strips. Basically, I needed to plot points on the plywood. First I stacked and clamped the two large pieces of plywood on top of each other. I then "plotted" the points from the plans with small wire nails. After marking and driving about 140 nails, I then moved on to lofting.
I then used the nails as little clamping posts to hold a 16 foot piece of window molding to the nails and drew a nice, fair line the length of the planks. Once all the planks are marked, it was time to start cutting.

How do I build a 14 foot canoe in a 15 foot garage?

The answer is I don't. The first thing I did was build a table to build the boat on. I needed at least a 14 foot table that was reasonably flat. It seemed like the best thing to do was to build it on wheels so that I could wheel it out in the driveway and wheel it back when I am done. My Model T sized garage just won't fit bikes, lawnmowers, etc and accommodate building a boat so this seemed like the best choice. Here are a couple of images of the table. The bottom shelf holds all the planks as I go

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Why?

Well, I had a wonderful Blackhawk Fishhawk (maybe Nighthawk) canoe years ago and seriously regret selling it. I looked for a used one or similar boat and no luck (at least at a price I wanted) . I decided to build and couldn't find a strip plan I liked. I ran across a guy in the Twin Cities (Eskimo Tom who will develop a plan for you to your specs......perfect.

http://www.finewoodwatercraft.com/ET_stitchandglue_home.html

He put together exactly what I wanted...solo, 26" beam and 14 ft long with a touch of rocker and tumblehome. I wanted to build a boat for a while so it was time.

I decided to do a blog on the construction because I found very little information on the web about building a plywood stitch and glue boat on the web. There are some guides and books out there. For this reason, I am not posting about the general method of building a plywood boat but I do want to log what I do and record the little tricks I am learning......along with my mistakes so people don't repeat them!