Port gunwale and deck carlins in place

After the troubles I'd been having with scarf joints giving way under the head of steam bending, I was careful on the port gunwale to avoid steaming the two scarf joints present there.  I steamed the gunwale in sections, and that's easy to do using the plastic bag method of containing the steam.

The gunwale bent without any breakage, and again I used most of my clamps to glue that on to the hull.

For the carlins that support the deck, I was able to use single lengths of sitka spruce left over from my mast stock, so didn't have to worry about joints.  Here the whole length is being steamed.

And here clamped in place.  I clamp in place while it's still in the bag, and can even keep steaming while bending the part into place.

After the wood has cooled down, I unclamp and slip the bag off, then reclamp and allow the wood to dry. The next step for these is to glue them in and plane them to accept the deck. 

Gunwales in progress

Next up to install are the gunwales that stiffen the upper edge of the hull and provide a place to glue the deck to.  I looked around through my lumber stacks and found a couple 10 foot 1 x 8 pine boards that were relatively clear and I started ripping stock for the gunwales.  I had to work around a few knots, so I cut them out and rejoined the pieces with epoxy-glued scarf joints.  I cut them with the bandsaw and then finished them on the disk sander, which gave a nice surface with square faces, and all pieces the same.

I was concerned about the scarf joint's ability to stand up to the heat of steaming.  I read somewhere epoxy is good to about 180 degrees, and of course the steam is about 212 degrees.  I scarfed a test strip and steamed it and was able to bend it to the curve of the hull without failure, so I went ahead with the real stock. Here I'm again using lay-flat plastic tubing as my steam box, which lets me clamp the piece in place while the steam is still flowing.

CRAAACK!  Yep, scarf joint gave way.  <sigh>  The epoxy in the area of the scarf looks kind of grainy or crystalized - must be from the heat.  I broke the joint the rest of the way, and reglued it, then steamed the wood on either side of the joint separately and clamped it in place.  After the wood cooled, I removed the plastic and reclamped the gunwale and left it for a few days while I worked on other things.

Then I removed the gunwale and applied thickened epoxy and clamped it on.  I used a few 23-gauge pins through the gunwale and into the edges of the bulkheads to keep things from sliding around too much while I used most of my clamps to hold in in place.  I didn't need to clamp very hard, but needed a lot of them to pull the hull and the gunwale together all along the length.  I cleaned up the squeeze-out and left it to cure.

After removing the clamps, it looks pretty good.  There's a slight flatness in the area of the scarf joint, but it's not very noticable and I can probably improve on that after the deck is installed and I fair the edge of that.

The gunwale on the other side has two scarf joints, though, so we'll see how that goes.  

After the gunwales, I'll need to cut and install the carlins (which are the same size as the gunwales and run parallel to them about 4 inches inboard, to support the inner edge of the deck). I may rip the stock for the mast/boom/yard from my stock of sitka spruce and see if I have enough of that leftover to use for the carlins. If so, that is long enough to not need any scarf joints. 

Seat edges finished up

After the epoxy cured, I brought the top edges down flush with the seats using a hand plane for the bulk of the work, then finishing up with a hard pad on the random orbit sander, then a soft pad to do the contour.

And finally, I put a fillet of epoxy on the underside to finish this off and close up any small gaps between the edging and the front of the seat.

Seat edges constructed and installed

I continued with the seat edge construction by using a router to round over all but the top seat edge. 

I applied several coats of epoxy on the three surfaces that form the seat-board slot, since it's easier to do that before assembly, and after that cured I applied thickened epoxy to the joints and clamped the parts together.

I didn't have any kind of bit to form the large round-over on the front of the seat edges, so I marked out the edges where I wanted to stop the cut.

And used a power plane to remove the bulk of the wood, then finished up with a spokeshave, followed by sanding with the soft pad on my random-orbit sander. 

I fit the back ends to the transom on each side, and then cut them to final length and rounded the forward ends, then coated the remaining untreated areas with epoxy.

On the starboard seat edge I routed a groove for the copper tubing to route the centerboard uphaul line and epoxied that in place.

And after it cured I trimmed off the excess tubing and made sure there were no burrs or sharp edges to wear on the line.

Finally, it was time to epoxy on the port seat edging.  I held this in place with a couple clamps and braces from the other seat front.  Short sticks support the edging at the correct height.  No screws or other fasteners needed.

And the next day glued in the other side.

I left both moldings just proud of the seat tops, so that I can plane/scrape/sand them down to the perfect height.  After painting, the transition should be invisible.  I like the feel of these edges - they are smooth and comfortable.  They add a little weight to the boat, but I think it will be worth it.

Seat edge design

I've been thinking about how to finish off the front of the seat edges.  The plans call for a square corner, and then a cleat 3/4" below the edge to provide a ledge for boards spanning the cockpit for a sleeping platform or rowing seat.

I was interested in easing the edge of the seat and gaining a little additional width.  I prototyped the shape shown in the photo below, which accomplishes that, and also provides a ledge to insert boards across the cockpit.  If I do use boards I expect to make them with a cleat underneath to fit the slot so that the top ends up even with the seat tops.

When I put my edge idea in the boat, though, I could see that I was going to have some interference with the centerboard uphaul line.  I threaded the line through the pulley and taped it down at the angle I expect it to run.

I plan to place a copper pipe in the seat edging to route the line, and I was pleased to see that it would exit the bottom of the edging in a fairly short distance.  The pencil line below shows the expected path of the copper tube.

With the plan in place, I started cutting stock for the two seat edges.  To keep the 6' 9" pieces under control during glue-up I decided to route a tongue and groove arrangement as shown below.  I sized the center piece to have a slot 13/16" high - enough to fit a standard 3/4" board with a little play.

Next I will round the edges and glue things up.

Seats installed

Now that the cockpit floor is installed, I next moved on to the seats.  The starboard seat gets a section cut out to provide access to the centerboard from above, which will be handy to have when installing the centerboard.  Since I don't much like square corners, I layed out a curve on the aft end.

I didn't cut this access the full length of the slot, but left it about 8 inches short.  The idea there is to have no seams at the aft end of the trunk.  I have heard that some boats with the cover cut full length could get some water splashing/seeping through the joints, leading to wet clothing, and a recommended solution for that was to have a shorter opening, so I'm trying that.  

For the long straight cut I set up a fence and used the jig saw, after first flattening the set out of the blade with hammer and anvil in order to get a narrower kerf.  

For the corner I used a coping saw, which worked out pretty well.  I should have paid a little more attention to keeping the cut vertical, but it worked out fine.

I rounded over the edges a bit with sandpaper. 

And then put the final coat of epoxy on the underside of the seats and let that cure overnight.

In the morning I spread thickened epoxy on all the cleats and edges of the seat front on set the seats in place. I took care that they fit pretty well, so didn't need any clamps - just a few 23 gauge pins to snug it down and get a little glue squeeze-out. 

I didn't glue the joint between the back of the seats and the hull panels; that joint will be secured when I apply a fillet of epoxy along the joint, which will be the next job.

I'm always glad when the big glue jobs are done!

Sole fillets -- new recipe

No, this post is not about how to cook up the catch from your latest fishing trip -- it's about the boat again.  

After letting the epoxy cure from gluing down the cockpit sole (floor) I removed all the clamps and put a fillet of thickened epoxy around the edges.

I was able to reach over the edge of the hull from outside the boat to do the area between B3 and B4 shown below, but the area shown above was done from inside. Working on hands and knees does slow down the process.  I ended up doing this fillet in two sessions.

This was the nicest fillet I've done to date.  I did sand it a bit to remove a couple high spots, but otherwise would not have had to bother.  

This great result is due to using a new recipe for thickening the mix.  In the past I have used wood flour alone, wood flour with a little silica, and West Systems filleting blend #405.  All those options produced good strong fillets with a fairly rough surface.  The wood flour closely matches the plywood in color, and the #405 is much darker in color.

For these fillets, I made a mix of 2 parts silica, 2 parts microballoons, and 1 part West Systems #404 high density filler.  It takes quite a bit to thicken up the epoxy (about  2+ heaping plastic teaspoons-full for each pump of resin), but goes on nice and produces a smooth fillet that seems quite strong, and yet is fairly easy to sand.  

The fillet on the left is the new one, and the one on the right was West Systems #405 filleting mixture, which I then had to fair with a microballoons fairing mix because it was too rough.  I then scraped/sanded the fairing mixture smooth.

Bottom line is that the new recipe is highly recommended!