Tig oxidation with high flow argon

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Hi. I recently switched argon bottles and started experiencing unexpected oxidation on my welds. Setup Miller dynasty dx200CK water cooled 20 torch with gas saver gas lens size 8 3/32 proprietary blue mix tungsten from arc zone Argon flowing thru flowmeter at 25 CFH and I can feel/hear what looks like good flow DC HF welding max 165A on 304 stainless 2 inch box tube with 1/8 and 3/16” walls.  Good prep, cleaned with acetone. I took apart torch but didn’t see any obstructions. Screen on gas saver is clean. Any ideas? At 25CFH I would expect clean welds. Even a fillet was oxidized.  I am also making sure to move quickly and avoiding over cooking the SS.  I gave it just enough Amps to avoid my filler from sticking. See photos. I apologize for my lack of skill. https://photos.app.goo.gl/uMxsYSs2Kbk1tyEr7Sent from my iPhone using TapatalkLast edited by zargnut; 9 Hours Ago at 05:54 PM.
Reply:what brand Gas Save gas-lens are you using?  CK brand?

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Reply:

Originally Posted by Oscar

what brand Gas Save gas-lens are you using?  CK brand?
Reply:Is your collet installed backwards?Is the O-ring on the back-cap there and seated properly?Are you using the proper insulator/spacer for that gas lens collet body?

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Reply:

Originally Posted by Oscar

Is your collet installed backwards?Is the O-ring on the back-cap there and seated properly?Are you using the proper insulator/spacer for that gas lens collet body?
Reply:I would remove the quick disconnect (use the regular connection) and try on some scrap to see what happens.  I would also check the gas line going into the torch within the handle.

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Reply:ok, will test tomorrow.. This is a relatively new torch, but I have definitely used it on some recent projects and had good results. this is a weird new issue.. Have you ever heard of getting a bad bottle of gas? contaminant?  Would be kinda funny if it was nitrogen...  same 125 brown bottles I always swap from Airgas...
Reply:Not that I'm an expert but 25 cfh seems really high.  You have a #8 cup and you have the gas saver setup.  You might want to try 15-16 cfh and see if that does it.  Maybe even down towards 12.  Too high a flow can also lead to shielding problems.  I think it is Shovelon who suggests cup size x2 for cfh rate.  It will take you 2 seconds to find out if that is it or if it could be a bad bottle.-DaveXMT304 with: 22A Feeder, or HF251 Hi Freq DC TIG air cooled
Reply:I think you are on to something with the gas IF the problem started when you changed bottles. You said you've welded successfully with this torch before. I agree with DaveC that you flow setting appears high...esp with a gas saver setup. The rule of thumb I'd heard for 'normal' torches is 2x cup size for normal steel, maybe a little higher (not more than 3x cup size) for stainless. So, for a #8 torch, 16-24CFH. Stainless, probably use the high side of that range. But, with a #8 gas saver/lens, I would expect ok results between 12-18CFH. [I haven't looked at you photos, so I'm assuming you're not trying some unusually long stick out?] Is there anything new where you are working that could be creating a cross wind or breeze? Shop heater/fan running that wasn't pushing air before? As you indicated, *something* has changed...it could be bad gas.Dave66=================Millermatic 211 (Transformer Based)Primeweld TIG 225X


Reply:Gas flow is way too high for a #8 cup....start at 15-16CFH and see what happens.  You can always increase if needed.I have had multiple bad bottles of gas, so it can happen.  All were bottles that had been switched from one gas to another and they must not have evacuated them completely prior to filling.  The difference is the beads had porosity and black soot....super obvious.Your tungsten is showing a color change (blue and purple) which means the post-flow isn't long enough.I don't say this to be mean (honest) but if those parts are anything you care about, you need to spend some time practicing just running beads, then on the joint configuration you're trying to weld before doing the actual work parts.  The 5th photo has so many areas of concern I would grind it out and start over.Check out my bench vise website:  http://mivise.comMiller Syncrowave 250DXMillermatic 350P with XR AlumaProMiller Regency 200 with 22A feeder and Spoolmatic 3Hobart Champion EliteEverlast PowerTig 210EXT
Reply:

Originally Posted by zargnut

ok, will test tomorrow.. This is a relatively new torch, but I have definitely used it on some recent projects and had good results. this is a weird new issue.. Have you ever heard of getting a bad bottle of gas? contaminant?  Would be kinda funny if it was nitrogen...  same 125 brown bottles I always swap from Airgas...