I am just gathering all this info about rack systems. I hear y'all tellin about welding on lines and havin the gas bleedin thru the ball valves.

Well hey, cant you simply sweat a pair of schraders, one upstream of the repair area and one downstream of the area to be welded.

Have one used to hook up a vacuum pump and the other used to introduce some nitrogen.

I know this would take a balancing act to get it correct , mixture wise ... but it would be far better than infecting yourself with fosgene gas all the time.

What are your tips/ techniques/ strategies for accomplishing a welded repair .... as painless as possible?