I'm working on another set of turbo headers and have a nitrogen gas purging setup.
I have a rubber expansion plug in each end of the tube with a hole drilled in it for nitrogen coming in one end and venting out the other end.
It is working good as the inside weld looks great.

I am interested in hearing what other gas purge setups guys have come up with.
Something that uses the least amount of inert gas.
I considered having the vent tube go to a water bottle so I could see the gas bubbing up like a water pipe so it would act as a one way check valve and I could monitor the gas flow that way too.

 

The water bottle is very good idea. I have never heard of nitrogen being used, but if it works, great! I was going to use heavy aluminum foil/worm clamps as my end caps.

 

I wrap a bunch of foil around the hose and slip it in the hose. Wrap foil around the tube abd hose. smash here nice and smooth and tape once around the foil to hold it to the tube, ground to the foil. tape the other side up and poke a few holes in it and set back purge to 8-12 cfm