by bartonmd » Mon Oct 03, 2011 9:01 am
You're over-thinking it... With sheet metal (and even tube), the shape is MUCH more important than the material... See it all the time on Pirate or whatever... A guy builds a cage out of Chromoly DOM, and another guy builds a cage out of poop pipe... They both roll, and the poop pipe cage holds up, while the Chromo DOM cage doesn't... One guy had a good design, and the other didn't...
I just use 1011 (A569... Very similar to 1018) 7ga (.179") low carbon industrial steel on my products, and it holds up great... Yeah, you could go with a better steel or chromo and get the same strength (albeit harder to work) with .165" steel or something, and save 10#; but the steel costs 3x as much, and if you aren't racing, the $/# trade-off is much different... Nobody would buy my $260 radiator skids if they were $400, but weighed 55#, instead of 63#... Same goes for my $165 oil pan skids being $250, or my $350 bumpers being $600...
Just use whatever steel you can get your hands on (usually 1011, if you get it from a welding shop or something), and use bends and flanges to make it stronger...
Mike