Tig welding stainless tube

[tigdummy]

Got an automotive project where I need to butt weld .060 stainless tube. Have some new scrap at work i have been practicing on. 50 amps inverter machine .040 T .045 F welding small sections at a time say 1/4 to 3/8" at a time skipping around I still see on the inside of the tube where the weld drops in at a very minimal amount. This is for exhaust on a turbo application will the small puddle drop effect flow that much? i am set up to back purge the stainless but haven't due to I am trying to get heat under control and it is practice.All input needed please sorry don't have a way to post pics. I get a nice stack of dimes just more concerned of the puddle drop and weather it is really an issue.

[kcd616]

Always remember you must purge the inside.
The gas flow has to do with the size.
Higher you can run the gas flow, purge, the cooler and cleaner the weld looks.
Sincerely,
Kent

[whateg0]

If it is downstream of the turbo, I think this would be a good application for Solar-B flux. I've always backpurged my SS tubing welds, though. You won't get an accurate impression of the weld quality without it.

Dave

[Rocky D]

Your weld will act differently when you purge the part...penetration will be a lot easier, so when you practice without gas backup, be advised that when you do it purged, you will penetrate quicker. Also for .060" material I would use a 1/16" tungsten, I s'pose since that's all I've used for the last 40 years...hard to get out of old habits. When welding any tube 100% penetration is best....keep in mind your exhaust tube will be expanding and contracting under use, not to mention the vibration, so a good weld is what you want.