Managed similar to that once, whilst mucking about on a quite day at work, set up a few 300mm long fillets and butts, in some offcuts of 5 - 6mm 304 stainless steel (brushed up nice and clean first of course).
The Difference was, we were doing it with a Tig set using a size 12 nozzle on a large gas lense, and using a mig welder to feed in the wire (found an old spool of Stainless mig wire in the stores).
Took a bit of fiddling with, getting somebody else on the wire speed control until got it dialed in, but when we did, I think it was the fastest ive ever Tig welded anything. Had three of them next to each other and was alternating around between them to not build up too much heat in one, and took no time to build up a 6 pass fillet on each
Pucka penetration, no undercut, perfectly smooth, real shiny bead.
Same thing as cold wire Tig welding i guess, but wasnt too hard to do once got used to the feel of it