I had a thought. Instead of getting another tank to purge my primary tubes before welding, could I plug off both ends and add fittings to plugs the same size as the hose to the TIG welder, fit hose from bottle to one end, then run a hose from the other end to the machine. I imagine I'd have to tape off the joints to be welded except for the one I'm going to weld, helping to keep to much gas from escaping. Or do you think it would still draw outside air into the mixture before it gets to the machine?

David