I've fusion-welded literally miles of stainless steel thinwall tubing in diameters from 2" to 6" while I was a welder/mechanic at Gallo Winery in Livingston California. During a modification of the plant piping before the harvest season began one year, we ran 8 miles of new 4" pipe. It was installed anywhere from 12 feet to 40 feet above ground level.

It's a little difficult to fusion weld with a MIG machine- - - - -my TIG isn't in working shape yet.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!