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Tried a new backing gas mix on a stainless job and it backfired big time
Last month on a food plant job in Omaha, I swapped my usual 100% argon backing gas for a 90/10 argon-hydrogen mix. The spec sheet swore it would give a cleaner root pass on the 316L pipe. Instead, I got a weld full of porosity and a nasty sugar-like deposit inside the pipe. The foreman made me cut out and redo 40 feet of 6-inch schedule 10. Learned the hard way that those fancy mixes are super sensitive to purge flow rates, and my setup wasn't dialed in for it. Anyone else have a backing gas story that went sideways?
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nathanburns5mo ago
Yeah, that's a rough one. A buddy of mine had a similar mess with nitrogen backing on some duplex. He thought it would be fine, but it came out looking like a sponge. Totally agree with @faith_torres83, sometimes you just want to stick with what you know works. Those special mixes really need everything perfect, or they'll bite you every time.
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faith_torres835mo ago
Ouch, that's a brutal way to learn! It's crazy how one little change in the mix can throw everything off like that. Makes you want to just stick with the old reliable stuff sometimes.
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