One more thing mark, Why are you weld etching? And what process are the etches from, tig mig? Is it just curiosity? I had to weld some 1/2 to 1/2 aluminum plate, with 210 amps tig....... not nearly enough sack to get that job done, so I borrowed some helium from air gas and did some penetration tests running in DC with pure helium, awesome penetration, full pedal was a little too much lol. Helium for those of you who don't know will make your tig welder super-powered instantly, it's better to run a 50 50 mix argon helium and use AC for the cleaning action, DC alu welds aren't pretty, also the helium will leave the bead kind of black, and must be brushed