Beginning the D4

I'm working on the D4 again, after 9 years.  I was at a waiting point in the canoe, so I stitched it together with my son, Alston.  He has watched me carry the parts for this boat around the entire time, so he was excited to help.

Recapping what was done 9 years ago,  I cut out all of the panels and the frames.  The panels are a luan plywood, and the frames are AC.  The transoms are 3/4" laminated from 1/4" plywood.  I wanted the option of putting a small motor on it.  I misunderstood the directions and laminated the bow transom as well.  I added an extra pound or 2.  Oh, well.

I am stitching it together with tie-wraps and 3/4" dowels.  I started by screwing the panels to the frames, mid-seat bow fore frame first, stern transom second, bow transom third, then the rest.  We loosely stitched the pieces together.  We will tighten, adjust, and tack the seams later.  Alston came in especially handy, since he crawled under that tiny boat, and fed the tie-wraps back to me.

Side view, through my work cart (next topic).

Front view.

Rear view.  Notice the daggerboard trunk halves, coated on the inside with graphite and epoxy.  These have been done with left over epoxy.

Making the Yoke

The yoke as designed for this canoe was a simple 2" dowell.  I wanted more flair, so I came up with a wavy yoke.  I suppose it is not technically a yoke, since I won't carry this canoe on my shoulders, and it is not designed for that purpose.  It ended a little oval, 1 1/2" x 1 3/4".

The yoke began life as 2 pieces of 1x4 poplar, glued up into a 2x4.  I couldn't see carving a harder wood, such as oak, at least not the first time.

I laid the curve out on the board every half inch.  The curve is just 1 1/2 cycles of a sine wave, calculated on Excel, with a 1/2" foot for mounting.

The shape was cut out, square, with a jig saw (I wish I had a band saw).  If you look carefully, you can see that the octagon has been marked, and the part to be removed shaded with a pencil.

I removed the shaded part with a shaper, a cheese-grater for wood, leaving a rough octogon.  Most of the material to be removed has been removed.  Only a little material has to be removed from the remaining corners to end up with a round form.  Being poplar, it was very easy to remove material.

I did the final rounding of the corners with a 1 1/2 wide, 100 grit sanding belt from the bargain bin at the Klingspor woodworking store.  Drawing the belt back and forth, like polishing a shoe, quickly rounds the wood.

It may not look like it, but this yoke is 35 1/2" long.

I used clamps when I glued it in.  If I did it again, I would use screws through the rubrail.

The Seats

The seats for the canoe as designed are open bottom - a piece of plywood over 1" cleats and supports.  I didn't want to leave it open for various reasons - it would be a hiding place for spiders in storage, it would be a pain to clean, and I wanted to experiment with floatation foam chief among them.  So I added a plywood bottom with foam in the middle, providing about 17 pounds of floatation for gear or provisions.  This complicates assembly, because the frame has to be installed after completion instead of being built in place.

After measuring the seat dimensions, I started with the frame on a piece of plywood.  The visible parts of the frame are from scraps of red oak that I have had for 12 years, bullnose trim  left over from stairs I built in a house I used to own.  The newels on those stairs were not loosely nailed to the floor, like in most houses.  They were screwed to the joists.  No one could crash through those rails.  The scraps were not long enough, so I joined pieces to make them long enough, using lap joints.  The hidden cleats were spruce.

This is a learning project, and this is my opportunity to learn about floatation foam.  I have had this flotation foam since 1999, but apparently floatation foam has a shelf life similar to epoxy.  It is still good.  Floatation foam is a Coast Guard approved, two-part polyurethane mixture that foams when mixed, like expensive Great Stuff™.  When mixing this stuff, the mixture is 1:1, so it is convenient to use identical disposable plastic cups (labeled A and B so you can re-use them for each batch) and pour each part to a line molded in the cups.  I mixed thouroughly, just until it started heating, and poured into the seat frame.  Below, you see the result of two pours on the bottom, and the other seat after trimming.  I trimmed using guitar wires, but it took four because they break so easily.

After filling with foam, I glued the plywood tops on.  The assembly is very stiff and light.

Mounting the seats was not as straight forward as I thought initially.  The plans had a measurent to the top of the seat on the centermost edge.  This measurement is different from the other side.  I used a level to make the seat as close to level as possible, smeared the ends thickly with epoxy putty, and screwed the seats into place using two sheetrock screws on each side maintaining 1/8" separation between the seat and hull.  I put 9 ounce woven fibberglass tape on the upper side, wet on wet.

Below, an installed seat.

Geezer Rock

Tonight Renee and I, along with several friends, checked out Arrogance at the Cat's Cradle.  Arrogance is the king of the Triangle bands.  There are probably 15 bands out there who would take exception with that statement.  Arrogance formed way back when - '69, I think.  They played together until 1983. They released 5 records, including Suddenly on Warner/Curb, plus The 5'11"Record long after the breakup.

They opened with "Not Unusal." That is one of my favorite Robert songs. Later, a great version of "Money'", but no "Open Windows."  I have to say I miss the old days when they walked onstage to the whistling song, and closed with "Puff, The Magic Dragon."

There were a lot of geezers there.  I'm not young by any means.  I can't remember JFK's death, but I do remember RFK's.  I would have been in the youngest 5% there, had so many people not brought their grandkids.

Attaching the Rubrail

Laminating the rubrail is a several day process.  The rubrail is made of three 1/4" thick by 1 1/2" wide plywood strips laminated to 3/4" thick.  They are glued on one layer at a time with a glue made of epoxy and wood flour.  You really need lots of clamps for even clamping pressure.

I don't have any 16 foot strips of plywood, of course, so my rubrail strips are 8 feet long.  I will stagger my joints for strength and for fairness of the curve.  On the last layer I will center the 8 foot strips on the sides and finish with 4 foot strips on either end.

I borrowed a few clamps to make 49 clamps total (thanks Rob and Carl).  On my 16 foot canoe, that is 25 per side, more or less, or one clamp every 8".  I glued on the first layer on both sides.  It bends vertically more easily than you would expect.  I used 10 ounces of epoxy for the putty to glue on 16 feet of rubrail.

After it set up, I noticed little waves in the rubrail.  There were depressions at every clamp point.  This picture shows it, although blurry.  The canoe is longer than the depth of field.

I was afraid to do only one side at a time, to avoid pulling the canoe assymetrical.  To try to correct the waves, I spread on the epoxy a little thicker and clamped over the high spot on the first strip.  This helped some: it reduced the waviness by about half.

Since the 2 layers has made the hull stiff, I decided to go ahead and put the last layer on one side at a time so I could use all of the clamps.  I used 44 clamps on each side - 1 every 4 1/2 inches.  This is a much better spacing.  I will make sure on future boats that I can clamp every 4 inches.

This is the finished rubrail, before shaping.

Taping the joints outside

My goal for this session of work is to tape the outside joints with fiberglass and do as much of the epoxy work as possible wet on wet.  I probably didn't say so earlier in this blog, but my real purpose in building this canoe is to learn for building a bigger boat.  Having a canoe at the end is a fringe benefit.

Yesterday I prepared for today's work.  I sanded the outside so that all of the epoxy was scuffed and new epoxy would adhere.  I rounded the joints outside to about a 1/2" radius with a belt sander.  After rounding the edges, I noticed several holes in the core of a couple of panels.

I had seen few voids from the cut edges, so I investigated closely.  I discovered tht I could push my thumb nail throught the veneer at these holes, across the panel, all of the way to the other edge.  I have to fill these to prevent rotting, so I got out the Dremel and looked for discolored lines or snall voids at the edges.  I routed through the veneer and first layer of the core.  I will fill the slots with epoxy putty, and cover with fiberglass tape to replace the lost strength.

Last, I laid out and cut the fiberglass tape.  Each piece was rolled like a scroll from each end to the middle, to make it easier to lay out, just line up in the center, and roll.  I laid them out, labeled.

I started early doing the outside joints.   The steps - prime the wood, fill the joints to make them smooth, and apply fiberglass tape.  Priming the wood is easy enough.  I used a foam roller.

I let the epoxy cure nearly an hour, then I mixed putty and filled in all gaps in the joints and all of the slots I cut to expose the voids.  As soon as I finished puttying, I began taping.  I taped the bow and stern (Which is which?), then all four chines.  I used  the scrap tape at the bow and stern between the chines to make fairing easier by providing a constant number of tape layers.  I also used a little woven tape to strengthen the slots cut over the core gaps in the plywood, since the plywood was only one layer thick at those spots.

I let the tape cure awhile, until it set.  Since I had time, I went ahead and filled in the weave of the biax tape with a thick wood flour/epoxy slurry.  It was closer to putty on the vertical surfaces.

Working wet on wet is definitely the right way to do this.  There is no sanding between steps, and that saves a lot of time.

Below, the canoe is all taped.

Flipping the canoe

I flipped the canoe over, and inspected the misalignment problem. It's easy enough to fix. My idea was to fill the depressions (4 of them) under the tape with epoxy/wood flour putty. fmiles on the forum suggested using strips of plywood bedded in putty as a filler less expensive than straight putty. I laid a strip of scrap plywood by the deepest spot, but it was too thick. But it was a great idea.

When I was butt splicing the panels together, I coated the bottom panels with leftover epoxy, so as not to waste it. These panels have little bend, so it didn't affect anything. But because it has cured, I have to sand for adhesion of the next layer.



I sanded quite a while, mostly smoothing down putty that squeezed through the joint from the inside. The putty spots are hard, jagged sandpaper-shredders. I prefer hand sanding: there is just something relaxing about it that quietens the mind and puts everything in perspective. I think I look forward to fairing. You can see in the picture how the 60 grit sandpaper has scratched up the smooth epoxy surface.

I spread epoxy putty in the depressed areas, as wide as the tape will cover. The idea was to build up the area under the tape level, and let fairing putty fill the space in between. 12 ounces of epoxy putty took care of the problem.

Unfortunately, in one area I took care of the problem too well. I built it a bout 1/32 inch too high. That would be a problem in fairing, and I certainly didn't want to sand through fiberglass tape. I knew this stuff is hard, but it hard to realize just how hard. 45 minutes of hard sanding by hand, with 3 paper changes, and I had it level. The high area was only about 6 square inches.

This is the result: