Inwales and Interior Fiberglass
Note: clicking the photos links to a higher resolution image
Now that the hull is turned, I clean up the sheer with my power planer. There's a bit of a 'hump' near frame 'B' (which is probably part of the problem I had near there), so I strike a fair sheer line with a batten, and use my power planer to set things right... it looks much better now (I only had to remove about 1/4" of the sheer, near frame 'B').
I notch the frames to receive the inwales, using a hand saw and a spade bit to form a slot with a round bottom. I'm not too worried about the fit, because I'll fillet these joints when I glass the interior.
I begin sanding the inside, which thankfully doesn't need too much effort, because there are relatively few epoxy drips from the planking process.
I pick up about $50 worth of douglas fir porch flooring for inwales and other purposes.
The notch will receive the inwale
sanding the interior prior to fiberglassing
I am getting ominous signs from my Bosch sander... several times, it inexplicably slows down for a few seconds. There's no sign of smoke, and no burning smell. I've been using the vacuum attachment, so it doesn't seem likely that the problem is sanding dust in the mechanism.
I'm going to try to resurrect my older Bosch unit, the one that died due to a seized disk bearing; I managed to free the bearing, so it may come back to life (once I extract the broken bolt). In the meanwhile, I'll keep an eye on the newer one.
Minor disaster occurs. I scarfed a couple of 1 x 4 douglas fir planks to make up a 16' long piece, which I then ripped on my table saw to form a pair of 3/4" x 1 1/2" inwales. While attempting to test fit one of them, the piece broke at the scarf. From the looks of it, it might have been 'glue-starved', or possibly over-clamped; it's the first time I've ever had a scarf fail on me.
The full thickness might have worked (save for the bad scarf), but the alternative plan worked a lot better. I re-sawed the remaining piece, which resulted in a pair of full-length pieces about 5/16" thick, and MUCH more flexible. These fitted into the notched frames with no problem. I then cut and re-sawed similar shorter pieces from a new plank to form a lamination, two pieces thick. The end result isn't quite as thick as originally planned (it's around 5/8" or so), but will be more than adequate, and probably even stronger.
I glue the laminations in place with an epoxy/microfiber mix, and clamp it using my big collection of 1" spring clamps. I then screwed it from the outside temporarily. Not having enough clamps, I can only do one side at a time.
The broken scarf joint
The port inwale, clamped up with nearly every 1" spring clamp in the shop. It is also temporarily screwed in; the screws will be removed after the epoxy cures.
I install the starboard side inwale, clamping it up just like the port side.
Time to fiberglass the interior. I'm doing this one section at a time; a 'section' being defined by the space between adjacent frames, from the sheer to the keel plank. It's difficult, because the beam of the boat makes reaching to the sheer plank a reach. I am using the 'wet' method, first coating the interior with resin before laying a pre-cut piece of 10 oz glass cloth into the space; by doing it this way, the resin helps hold the glass into place as I saturate it. The joints between the frames and hull get a fillet of epoxy thickened with #403 milled fibers, and the joint gets an additional layer of 4" glass tape over it.
It's going to be a long hard slog to finish this. It is also not super-neat, since I've got corners and angles to deal with. Thankfully, the interior will be painted, and the seats and floorboards will distract from the rough finish of the interior hull, like most boats.
Cost/Time summary: 184 hours, approximately $2138. I'm now guessing that completion will require another 150-200 hours, and the total cost will approach $3500-$4000. I guess I'm paying around $10/hr for the pleasure of building this boat... not a bad price!
To reach into the hull for interior glassing, I've got the boat tilted as far as possible on the cradle.. but it's still quite a reach
The first 'section' glassed... difficult to reach inside, and hard to do neatly. I'm trying my best!
I figure another week or so of this... and then I'll be able to move off to the centerboard case construction, which should be a lot more interesting.
More sections fiberglassed... and this is really tedious. It is made even more difficult by the height of the cradle; even with the hull 'tilted' as far as possible, I have to stand on my toes to reach the keel plank.
The interior fiberglass is finally complete... a very tedious process. I picked up two more units or epoxy along the way, as well as 8 more yards of 10 oz. fiberglass cloth, for a total of around $225.
Next up: construction and installation of the centerboard case. I'll hold off sanding the interior fiberglass until this is done.
Page log:
The Project Resumes... Floorboards
Essays:
Using epoxy in cold conditions
Errors, bad judgments, and lessons learned