Just some food for thought:
Dan L wrote:
Interesting project, keep the pics coming.
Re: the frame twist, a few years ago I was working on a military vehicle project and on those with boxes on the back, ie, "campers" they used a special 3 point pivoting mount system that isolated the box from the frame. It was designed such that a moment could not be transmitted from the frame to the box.
Do some searches and I'm sure you can find some info/pics of similar mounts.
Dan
I have seen this 3 point system purposely used on an "Earth Roamer type" off-road build, either on the net, or a television documentary. For absolute frame twist security, it is the only way that makes sense, and I made a mental note of it. If one was to mount the box shell in two forward places on the frame, the cabover portion of the box is unlikely to flex different enough to touch the cab. The single point mounted rear of the shell can lift/travel considerably from the truck frame without shell damage.
On the other hand, I'm sure most TC's and Mini/Motorhomes do twist considerably more than their owners realise. As long as the shell is fairly homogenous, the bending stresses are not concentrated in one single area. It is the reason that windows, and now often doors, have rounded corners and the glass can somewhat "float". Marine windows are often entirely round. Boat structure cracks and leaks are even worse than campers, of course.
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Jfet wrote:
recycler wrote:
you could always just do like i am and fiberglass over the plywood making it a one piece roof put you some waxed shimming on the sides to wrap over so you can add the siding of choice later.. as for attaching the plywood grind the tubing for some bit and use liquid nails and and screws
It does seem like fiberglassing the plywood would be the easiest and maybe cheapest solution. Considering fiberglass boats last like 30 years even when exposed to the elements...
I would use sikaflex, which I guess is similar to liquid nails, to fastent the ply to the steel...maybe with some screws too although I doubt they are needed.
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recycler wrote:
the original one piece fiberglass roof to mine is about 45 years old and is in fair shape yet...
Speaking of marine construction,
here is a thread discussing good old fashioned painted canvas decks. Most important to note is that in this post, the gentleman mentions his ordinary painted cotton canvas has reliably served as a waterproof deck (roof) for
55 years. Quote:
"The original painted canvas has been on my boat for 55 years. It's kept on the water all year long in a covered slip. I re-coat the paint every 6-8 years." EPDM is far from a new concept, except probably even more rubbery and durable than paint. EDPM would be my roof of choice.
I did try the lowball "painted fabric" idea on a plywood picnic table we received as a gift. The table was meant to disassemble and be transported for campouts, but the builder thought that if thin plywood was good, more was better, so he used 3/4 inch ply. It weighed a miserable ton and we finally left it permanently set up in our backyard. Anyone that has merely painted plywood in an effort to preserve it outdoors, knows that the raw plywood surface grain cracks within months.
Finally, in an effort to forestall chronic repainting, my wife let me have some old, semi-rotten, cotton sheets that we had used to start new lawn. I experimentally applied a very wet coat of ordinary leftover latex house paint to the tabletop and wrapped the sheet over, then immediately saturation-painted the dickens out of the sheet surface. Ten years later, the maintenence-free table top was still in great shape, but the feet had rotted off, so I threw the table.
My son also covered a low-cost homemade truck topper with thin painted cotton. The redneck topper was built with a superlight wood frame and styrofoam sheet. It had a plexiglass front and rear window incorporated and a rear door with a sealed plastic hinge. After the latex house paint was dry, it was very light, stiff and waterproof. He work-camped in it for a summer. Unfortunately, it wasn't fastened well to the truck box and eventually tore loose in a windstorm coming from the rear while parked. The aerodynamic shape apparently kept it on during driving. I don't know how long the surface might ultimately have lasted, but many quality latex house paints are rated for up to 50 years. Because it breathes vapor, latex is inherently less likely to peel as opposed to oil paints.
Wes
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