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Old 05-01-2008, 02:49 PM   #1
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while doing some research on welding SS I came across a thread on Miller Welding's forum about welding keggles and back gassing. A member claims he purges his kegs with dry ice before welding? I was under the impression that ss would oxidize in the presence of CO2. Any thoughts?
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Old 05-01-2008, 03:16 PM   #2
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noone has any thoughts?
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Old 05-01-2008, 03:22 PM   #3
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Quote:
Originally Posted by pickles
noone has any thoughts?

If you wait more than 27 minutes, someone who knows something about welding may chime in.

I know nothing about welding, but I'll offer this:

We use CO2 to protect beer from oxidation. Don't kow why it wouldn't work for SS.
We keep CO2 in stainless (kegs) for long periods of time, with no worries.
In fact, I'm struggling to see how CO2 would "oxidize" anything, as oxidation requires O2.
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Old 05-01-2008, 03:26 PM   #4
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sorry i'm about to leave my computer for the day and wanted some quick advice
thanks for your help
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Old 05-01-2008, 03:28 PM   #5
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Should be OK. Some people use CO2 as a shielding gas for MIG welding
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Old 05-01-2008, 04:31 PM   #6
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a mix of helium and argon is preferrable for stainless welding.... but any gas that pushes the oxygen out of the way is exceptable for back gassing. On the weld itself, you MUST use either the helium argon mix or pure helium. Pure Argon won't work on stainless. It'll weld, but you'll never get a water tight weld.
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Old 05-01-2008, 05:15 PM   #7
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Apologies, but argon is the purge gas used in stainless steel welding, both automatic machine welding and hand welding. Co2 should not be used for stainless steel welding or back purging.

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Old 05-01-2008, 06:09 PM   #8
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I would also be concerned with the temperature shock between the weld and dry ice. If that weld cools too quickly it will crack.
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