On Sun, 28 Feb 2010 06:52:53 -0800 (PST), mark
wrote:

My original jeep CJ-7 frame has rusted out and I was thinking of
building a new one from aluminum. Would 2 X 4 X 1/4 wall (if that is
even available) box tubing have the equivalent strength of the stock
1/8" wall steel frame? I would like aluminum because it will last
forever, no need of any paints etc..., very easy to work with and
cheaper than building a steel one and having it galvanized. My second
choice would be stainless 1/8" box tubing.

You do NOT ewant an aluminum frame. Perhaps stainless steel.
Aluminum frames on a jeep WILL flex. Particularly a 2X4 x1/4 tube.
ANY time aluminum flexes it is a stress, and all stresses are
cumulative. Frame life would likely be measured in months.

Steel is different. It has an elastic limit, and as long as that
loimit is not exceeded, no cumulative stress occurs.

I'd build a stainless steel TUBE frame if I was going to the trouble -
but Iron Horse (I believe that is still the name of the company)
supplies ready made replacement frames at a very reasonable price.