vrijdag 28 september 2007
The deck + cabin-sides have been laminated. It turned out to be messy work, mainly due to the small walking area in the hull. There were quite a lot of bubbles and wrinkles in the final laminate, which for the greater part already have been patched. In the next hull half I won't laminate the deck and cabin side in one go again.
After the laminating/patching, the bulkhead were placed and tacked/taped into place. Unfortunately I didn't get a nice(r) picture.
The forward bunk bulkheads only fitted so-so (after some adjustment the fit was good enough, though). Fortunately the beambulkheads fitted very well. Hans worked very hard to place them at exactly the right angle. I'm certain they're fixed accurately enough. The parts of the bulkheads which will be cut away later are tacked in place with a quick filet.
To place the beam bulkheads on the gunwale line exactly level and exactly the required distance aft of the form frames I made a jig of two battens.
The lower part is screwed to the frame, one side exactly matching the gunwale-level-line..... ....the upper part exactly matching the gunwale-reference-line on the bulkhead and shifting the bulkhead the right distance backwards with the extra batten. Jay did a similar thing. Works great.
Now I first have to fit the centerboard case. The cockpitfloor and the bunks can't be fixed until the case is in the boat. I hope to fit the case somewhere next week.
maandag 24 september 2007
To make the panels fit, I first temporarily attach the panel about 10 cm above the cabin-side, and then use a yardstick to trace the outline of the cabin-side on the foam. Then I cut the foam at a 45 degree angle with a jigsaw. Like this the cabinroof fits quite well on the cabin-side. No big gaps.
I used PU-glue on this joint, but it mainly made a big mess. Now I know again why I planned only to use bog to glue the foampanels of the main hull.
maandag 17 september 2007
After that I made some progress building. The planking of the lower hull-half is ready. I laminated the first 2,5 meter of the hull (beginning from the stern) and then ran out of cloth. I thought I'd bought the amount of cloth Ian Farrier had estimated, but clearly I didn't. I'll try to get some new cloth this week.
When laminating the outside of the floats I had a lot of trouble to get a bubble-free and well adhered laminate. One thing I do since then is to coat the foam with epoxy and lay the cloth when that coat is getting sticky. Like this the foam is saturated beforehand so it doesn't suck epoxy while you're busy trying to wet out the cloth. Also you can first tack the cloth bubble&wrinkle free - after that wetting out is quite easy. Downside is of course it's more work than draping the cloth on dry foam and do one wet-out. I'm using peel ply on the whole surface I'm laminating. I wonder if this is necessary, or am I overdoing it? Maybe it is sufficient to use peel ply in places where a good bond is necessary (like in taping areas). On the other hand I'm not so keen on sanding the laminate prior to further laminating/filling/coating as I'm afraid it can weaken the the laminate (and it is extra work, but so is putting on and wetting out peel ply). Ideas anyone?
I transfered the position of the frames to the inside of the foam using my frame-positioning-device shown below.Making sure the block of wood is straight against the frame I drive the nail through the foam from the outside every 20 cm or so. Then I put the block on the inside of the foam with the nail through the holes, and mark the position of the frame and draw a line with a flexible ehrm.... yardstick(?).
I believe this is accurate enough. Even better would probably be to use a straight needle held directly against the frame, but I don't have any needles in my workshop (who would?). Nails and scrap wood on the other hand......
dinsdag 11 september 2007
For planking we mostly used 20 cm wide foamstrips which works fine. We used a few 30 cm wide strips in the middle of the hull and some 10-15 cm wide strips in very curved sections (like the bow).
We only used a heat gun a bit to bow the foam strips in the large curve near the keel. For the rest the strips could be bent and held in place easily with two (20 cm strip) or three (30 cm strip) screws on each batten.
In the bow section I removed the battens on the flat section just below the gunwale-line. This section should be straight from frames 1-5 (checked this with Ian Farrier). The only way to achieve this is - as far as I can see - to mount seperate battens in the section between frames 1-5 and 5-12.
At the junction of the flat section below the gunwale-line and the curved part of the hull, I didn't try to cut the curved strips to the correct lenght. In stead I just let those strips long, and butted the flat section against them.
Here the grooves between the strips have been filled with putty. The edge at the straight section has yet to be filled. At this edge I'll cut the curved strips to the correct lenght once the hull is out of the mold.
vrijdag 7 september 2007
The workshop is quite full now.
Putting the battens on the frames is quite straightforward, except in the bow section where the battens have to be twisted a lot. Tip for future builders: don't put battens in the 'straight section' just below the gunwale-line until you're finished planking the main bottom section. You'll have better access.
I made four 30 cm wide foam strips out of one foam panel and test-fitted one strip. It bends in quite easily without heating the foam. I use Divinycell foam in stead of the corecell most builders seem to use. Maybe corecell is more ridgid and doesn't bend this easily.
Just like Jay I wonder what benefit heat-bending the foam will have? As long as I can bend the foam without breaking and without much force, I don't really see the point in heating the foam with all the extra work and the risk of deforming it in not wanted ways. Any thoughts on this are much appreciated! For now I'll start heating the foam slightly in the first (lowest) curve and see how it goes. I heated the first test strip like this - but a bit too long on one spot which made a brown mark on it. No damage done, however.