http://www.mig-welding.co.uk/calculator.htm
^That's a handy page to look at if you're looking for what thickness steel a welder is likely to weld. In fact, the whole site and forum is really really good.
I'm intending to use a 130A mig for the chassis tubes and hopefully for the 3mm brackets. If not then I'll tack them using the 130A and borrow a bigger welder to finish them
