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Sealed tube welding

Posted: Mon Apr 10, 2017 12:30 pm
by DrDogwood
First off I wanted to say Thank you for what you have posted I have learned a lot. Probably the best tip was going to a gas lens set up Helped my tig work immensely. But now I'm having some issues that I haven't seen covered yet. I and assume some others are having trouble when welding tube that will be sealed up when done (as in both ends of the tube are capped off). when I get to the end it seems like the pressure that has built up in the tube keeps pushing the weld out of the seam and filling it with unshielded gasses so I get porosity. any help would be appreciated. I don't seem to have trouble with the mig or maybe I don't notice it as much but with the tig it's getting frustrating.

Re: Sealed tube welding

Posted: Mon Apr 10, 2017 5:13 pm
by cj737
Very similar topic here. Answers are the same.

http://forum.weldingtipsandtricks.com/v ... =5&t=11510

Filling the tube with inert gas doesn't solve the issue either. The reason you may not have had the problem with MIG is the speed at which you are adding wire. You can get away with it because the amount of filler overcomes the pressure blowout. But it's still a better bet to rotate the welding or best, let cool and naturally dissipate.