| The hatch lid has
to hold its shape. According to various sources I've read on the
web, and in the plans I have, earlier lids could tend to
straighten or lose their curve, or in some way be unstable. I did not want to frame my lid from plywood. Plywood's greatest benefit is delivered in sheets rather than narrow strips or bands, and I think it tends to be a bit heavier than ordinary pine, per cubic inch. I used clear pine, and cut my curves on a bandsaw. I also used pine for ribs, and made the ribs wider in the area where my tail lights would be. This would have the effect of making a thicker cross-section in the area of the lights, making room for the light fixtures themselves. The outside surface of my lid is sheathed in 1/4" plywood. Since the lid is about 5 feet long, I decided to use a single piece of plywood with its outer grain running lengthwise . There would be no seams, and the usage was more economical... though probably only in my mind. The problem with bending the plywood on this long axis, is the the plywood is more stiff in this direction and will act to straighten the lid. It certainly did act to cause the lid to bulge outwards slightly in the middle of its bottom edge, which will complicate the bottom seal project. In thinking of this after a couple of years, I could have used a thinner plywood or paneling to sheath the galley lid. I did manage to make a decent seal for the bottom edge of the lid, in any case. |
I do have what I
consider to be a very sturdy and very stable lid. I do not
think it overly heavy. I sheathed the inner surface of the
galley lid with 3/16" plain paneling after I'd finished putting
the aluminum skin on the trailer and the galley lid. The lid is designed to provide a wiring chase for the tail lights, with its own covering, so i do not have to remove the entire inner cover if the tail light fixtures need servicing or repair. Two light fixtures and switches are mounted on the inner lid to provide lighting in the galley area. One thing did not work out very well for me. I installed air springs to support the lid, the same as automotive hatchback lids are supported. The units I have worked for a short time, but now they are effective only on very hot days. I believe that I could replace them with somewhat heavier units. I would not have to have a prop that I now use, for holding the lid up. Somehow, I do not feel any urgency in replacing them. |
 left picture is the galley lid framework, upper edge is nearest the camera - right picture is a detail of the lower edge framing as seen from the outside surface |
  upper picture shows creating a fair curve line for inner lid surface lower picture shows blocks glued and nailed in place, for attaching inner lid paneling - curved line is traced on piece of wood placed under paneling strip, cut with bandsaw |
| I mounted the
galley lid temporarily while I fastened the plywood to the
framing. I used the same ratchet straps and rigging that I used
for holding the sheet metal to the roof, earlier. I used the
same kind of bugle head screws that are used in sheet rock work.
They are self-countersinking and have an agressive thread for
holding sheet goods in place. You will see penciled "X"s in
place along the right edge. This is where my wiring is, and I
did not want to damage it. You will see the grain running lengthwise, so that I could cover a 5 foot long surface without a splice or seam. The 1/4" plywood was more than I needed and I could have done very nicely with 3/16" paneling. I was worried that the plywood would be springy enough to distort the curve of the lid. I was pleased to see the curve hold its shape when the rigging was released. Well, the bottom did bow out across the bottom edge a little but it was manageable. |
 |
Galley lid edge molding for the teardrop trailerI made a form for the exact shape of the hatch lid (as well as my skills would allow) - this would have to be very accurate so the edge molding I made with this form would not tend to want to straighten the lid - this molding had to also be flat in the plane of the plywood form when it was released from the clamps.This was a fairly robust piece of molding. I annealed it before forming it and then had to repeat the annealing during the project. It was cut from 2" x 2" x 1/8" aluminum angle, and I ripped one edge of it to 1 1/2" using my bandsaw on its slowest speed. The cutting turned out very nice, was very safe and had no attention-getting moments. Minor cleanup work with a file is all that was needed. I have a perception problem that kicks in at odd moments, and so I had to pay particular attention on bending the second molding to make sure I had a true mirror image of the first molding, instead of a copy of it. A molding like this is much like a spring, even when annealed. It will spring back a little when released from the clamps. What I had to do was manually bend the molding a little bit extra, after it was released from its form, then check its shape by seeing how well it fit back on the form. Adjust by pounding, if bent too much. |
 the edge molding for the galley hatch is clamped to a plywood pattern for shaping |
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I use various bits of scrap wood
for pounding blocks when shaping aluminum. This particular
pounding block should actually have been about one inch
longer. A bit of skin at the base of my forefinger got sorta
folded over the top edge of the block once. There is a
reasonable limit to how cheap you can be. Use a bit longer
block.
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A little safety moment...
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