Wall construction?

[Roly Nelson]

The 1/4 Nelson Stacker has 1/4" sides, 1/8" roof and hatch lid. No problem with So Calif heat and cold. Build your tear as suits your locality. I'm all for keeping it lightweight, so far, only 245 lbs!

Roly, just another dreamer and builder of off-of-the-wall teardrops.

[riverfront]

Roly! I put your site in my favorites! Great workmanship and ideas! Nice pics! You are quite the craftsman!

[Chris C]

The 1/4 Nelson Stacker has 1/4" sides, 1/8" roof and hatch lid. No problem with So Calif heat and cold. Build your tear as suits your locality. I'm all for keeping it lightweight, so far, only 245 lbs!

Roly, just another dreamer and builder of off-of-the-wall teardrops.

Roly, I want to know how you plan to keep that ultra-light teardrop on the ground when pulling in a crosswind?????

[Roly Nelson]

Well Chris, I have not thought of crosswinds, but I suppose I could stack a few cement blocks on the floor right over the axle. Or, how about a spoiler in the front and keep the hatchlid open to create some down-thrust at high speeds. In all truthfullness, it is well known that here in So Calif, all days are fair and sunny, it never rains and high winds are unheard of............. :-) Hmmm, now you have me worried, guess I'll just keep in in the garage, stacked safe and sound up against the wall.

Roly, with tongue in cheek and a great big

[jplock]

The construction I have been using is 7/8" x 1 1/2" studs mounted flat. The exterior plywood wall is 3/8". The inside plywood wall is 1/4" birch plywood. The insulation in the walls is 3/4" styrofoam. The ceiling plywood is 1/8" luan mahogany. The Roof is going to be 2 layers of 1/8" mahogany luan. ( Which I got on sale at Sutherland Lumber for $7.99 a sheet.) The Beams in the roof is 1" x 1 1/2" spruce. The insulation in the roof is 1 layer of 3/4" styrofoam I used in the walls, and 1 layer of 1/2" styrofoam it gives it a total of R-8 in the ceiling, and R-5 in the sides. I plan to use .020" white textured aluminum puchased from Mac's Aluminum here in Broken Arrow, OK. They are a supplier of RV siding they estimated about $ 280.00 for the aluminum. It is purchased and cut from 4 foot wide stock or 10 foot wide stock. They also bend joints for the seams in the roof it is made to your specifications.

Also does any one recommend a time tested contact cement for attaching the aluminum to the plywood?

Thanks!
jplock

[madjack]

JP, I would not recommend contact cement...we floated our skins and of late, most who glue their skins, use something like Henry's 663(or similar), which is a rubber cement formulated for putting down outside carpet...
madjack

[Cary Winch]

Riverfront,

One pro for plywood construction that was missed is structural strength. While it is possible to build a unibody like stick built design it takes alot of thought and planning on the engineering end to get it right. With a plywood construction you have a very rigid body easily. On ours the trailer frame is not even structural in holding the body square and straight. The body does that on its own and you save a bunch on frame cost and weight.

With a 3/4" wall you proabably won't see condensation on the plywood until well into the low thirties and even then just near the bottom. Definetely do insulate the roof though with solid foam to prevent condensation on the ceiling.

JP,

Do not glue the aluminum on. Free float it like Jack mentioned. Just use a heavier gage and it will lay flat nicely. We use .040. The thermal expansion of the aluminum is just too much, you will experiance bubbling of the aluminum for sure.

Cary

[madjack]

Cary, I am curious, do y'all experience any "oil canning" on the sides...we used .032 Al and when left in the sun for a period we get some minor oil canning in the area between the door and hatch and above the fenders....we get none on the roof which is floated over a ply substrate...
madjack

[Cary Winch]

Jack,

That is the are we some slight lifting off the plywood too. It is almost not visible, you have to push in on it to really see it. I would think the .032 and the .040 are going to be the same result.

Way back when did experiments with bonding the aluminum to the plywood that was the worst are for seperating, most suface area I assume.

Cary

[madjack]

Cary, yep that is the largest open area...the oil canning is only visible in certain light, IF you know what you are looking at...I believe we can live with it and your right .008 shouldn't make a real big diff........
madjack

[Cary Winch]

Jack,

Sounds like you are seeing the same thing we do. If it were glued and it popped itself off in that area, believe me it is waaaay more noticable.

The roof is probably swelling out in the sun too, it just is not visible I have noticed. If you put a staight across it you will see it though. Things like seams, roof vents and front windows help restrain it and greatly minimize this. Ones with nothing attached to the roof swell out more in the sun. Nothing to worry about as long as you are attached well enough on the edges. I have see the sun rip the roof off of the edge if it was not retained well enough (too short of screws and no glue) in one of our experiments. This is why we glue, staple and screw the edges down.

Cary

[riverfront]

Thanks everyone for the input!!!

As in JP's pic above, is it best to have the foil faced inside or out as he has it inside?

Cary, In all the reading most say you have to have sidewall insulation esp. if you will have air which I plan on installing, but if I understand you correctly if you are using 3/4 plywood, sandwich insulated sidewalls are not needed? I plan on a painted exterior on this project! I would prefer the faster construction of plywood but would be willing to build sandwich if it is advisable!

I also learned from Cary and MJ that AL is best not glued! That would make it a much easier job!

Again thanks for everyones input!

[Chris C]

Foil reflects heat. I hate heat. So I'm putting the foil to the outside. Not right, not wrong, just the way I plan on doing it.

[toypusher]

........So I'm putting the foil to the outside...........

When might that be???





(sorry, don't mean to hijack)

[asianflava]

So I'm putting the foil to the outside.

Is that so you don't have to wear it as a hat?