Steel framing for mini-hopper

[antilies]

I was wondering if creating a frame for the mini-hopper from 1x1x.120 would give me a strong enough fram to withstand many years of service and still keep with the "lighter is better" theroy behind tear dropping? The reason that i was looking at a square tear design was that getting steel bent to match the standard profile of a tear would cost a bit too much here in central PA. But i have the chop saw and grinder and welder to be able to do this with simple angle cuts. The other question was getting some form of insulation in between the outside and inside walls. The purpose of this critter is for long term deployment in a remote location. I'm not sure i'll ever build this "tear", but i'd like to get as much information on the build of this thing as possable. I was thinking of skinning the thing in aluminum. and fininshing the inside in 3/8" luan. I'm just trying to figure the plausability of the ideas in my head for a small budget.

Aside from that, i was wondering if anyone had any information on buying that steel her in the Carlisle PA area?

Thanks guys
Bruce

[alaska teardrop]

Bruce,

You can have the .120"x1"x1" tubing bent with a hydralic or manual tubing bender that has the correct mandrel. Or you can bend it by hand around a jig using a large rosebud on a torch. 1" extruded polystyrene works well for the insulation. If you inset the ribs you can get a full sheet of foam over the top of the ribs (no thermal bridging) and another 1" fitted between the framing. You won't need the 3/8" ply for strength (save the weight). Here is an example:

Edit: The example uses 1/16" (.062") for the cabin framing, which is plenty strong and saves more weight.