Purging and tips for welding 1.5” 304ss tube 1.6mm wall

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Last year I decided I wanted to learn to TIG weld. So I took myself off down to my local college and did my Cambridge Institute Level II course (the one where all the test pieces have to be done in the vertical position). Its been I while since I passed but I have now bought myself a TIG unit and shall shortly be attempting my first TIG welding project.I plan to make an exhaust manifold using off the shelf 1.5 inch 304ss 1.6mm wall bends.I have never done any work with pipe so have a few questions.1) I would like to purge my welds. What is the correct procedure for getting an argon supply for this.Do I need another bottle or can I just T off the original? Surely the T would have to be before the regulator so as not to mess up the metering of the flow of argon to the welder?2)Can anyone recommend a world procedure for this sort of stuff? I was just gonna start with approx 60 amps, 1.6 mm filler and a thin ground 2.4 tungsten.2) Any other tips for welding small diameter tube? Thanks,Doug.
Reply:Get'm, Zap!If you don't have the time to do it right, then you definitely don't have the time to do it over.
Reply:Originally Posted by ClanweldGet'm, Zap!
Reply:You can "T" off the original tank. do it ahead if your flow regulator and use some type of regulating divice for your purge. I just used a simple thumb wheel type shut of valve with a 1/4" line into my tube. I would open it up slightly,it only needs minimum flow, let it purge the tube using a piece of scotch brite to "plug" the end, you dont want to build pressure just get the air out of the tube. Pretty simple stuff. I am sure you will get the machine dialed in properly once you get welding so there isnt much to say there.Hope that makes sense.Dan.Repair Specialties LLC
Reply:Originally Posted by ClanweldGet'm, Zap!
Reply:You can tee off after the flow guage or meter.  You will need to increase the flow to make up for the purge line.  If you plan on a lot of purging you can get a dual flowmeter.  A piece of cardboard taped to the openings will surfice to keep the purge gas in.  Bring the gas in at the lowest point you can and leave a small venthole at the highest point you can.  Argon is heavier than air so it will fill the tube from the bottom up.  If you want a dual meter now is the time to get it.  buy it outright or if it's coming as part of contractor or tig/stick kit trade in the kit reg for the dual.DennisThermal Arc 185-TSWMillermatic Challenger 172VictorO/AAtlas Craftsman 12 by 24 LatheEsab PCM-875Wholesalem Tool Mill-Drill
Reply:Just wrap some aluminum foil around your purge line stuff in the pipe double or triple fold foil over the other end and tape around it with masking tape punch an 2 1/8th inch holes in the end use very low flow argon give it time to purge out . That depends on the length of pipe
Reply:Argon is heavier than atmosphere so you want to fill from the bottom. This will push all the O2 out the top.The foil and tape will work for the end that you insert the argon let the other end stay open once a match inserted into the open end self extinguishes you are full of argon and can cap both ends and stop the purge flow. This will save you money on argon pouring out on to the shop floor and might save your life (build up enough argon and you go out just like the match. During the purging process you want the flow very slow so as not to mix the argon with the atmospheric gas.   Fat Fab Alaska CWI 27years Heliarc
Reply:Good info fat-fab !  I like the idea of capping it to save wasting gas. I never would have thought that method would work if I had not heard it from someone else. Thanks for the idea !Dan.Repair Specialties LLC
Reply:Originally Posted by Fat-Fab.comArgon is heavier than atmosphere so you want to fill from the bottom. This will push all the O2 out the top.The foil and tape will work for the end that you insert the argon let the other end stay open once a match inserted into the open end self extinguishes you are full of argon and can cap both ends and stop the purge flow. This will save you money on argon pouring out on to the shop floor and might save your life (build up enough argon and you go out just like the match. During the purging process you want the flow very slow so as not to mix the argon with the atmospheric gas.   Fat Fab Alaska CWI 27years Heliarc