Someone asked me a question today and I felt I didn't give a satisfactory answer. It was can you mig aluminium, and if you can, why tig? My answer was that tig is cleaner, more precise, produces a better weld with better fusion and the Ac gets through the oxide layer. That sort of thing. So I realised I've no real idea about mig for aluminium. How does it work? Is it Ac too to clean off the oxide? How, given aluminiums specific heat and conductivity can you achieve speed but still get good penetration? I'd be grateful if someone with in depth knowledge of the process could fill the gaps in my education. Carl.