Gday from australia, and cheers for having me. I work for a company that builds faraday cages, we are currently quoting a job for a low frequency shilded room for an electron microscope. Its essential a box made from 6mm aluminium sheet, room size is roughly 7200X6200X5200, quite large, sheet size is going to be 1200X2400 and every join and corner needs to be welded. The sheets are going to be screwed down to fire-rated plywood before welding out so warpage will be less of an issue than the plywood smoking out and interupting the weld. My main questions are what would be the best process and procedure wor welding this room. From what little knowledge i have with aluminium a spoolgun is reccomended with straight argon or argon/helium. Will each sheet need to be v-ground for a v-butt weld or can you get away with a slight gap without v-grinding. also is it possible to weld vertically down with mig aluminum? Bear in mind that the welds are non-structural and purely for fusion of the sheets.