[Stringfellow]

Hi all, I recently encountered an issue with my setup.

I'm running a Thermal Arc 186 with a CK9 + 45V44 gas lens and Furick BBW cup running about 27 CFH 100% argon. This combo has been great and performed really well as recently as last week. I use it for welding mostly 4130 thinwall for experimental aircraft stuff. But I am definitely a hobbyist and a novice.

The other night, just doing some open beads on 16ga at 60A, the weld suddenly started to go all to hell like I was losing shielding gas coverage. Greenish uncontrolled arc, instant burn-through, popping/sparking, etc. This would happen after a normal start, and about 10 seconds of normal welding...suddenly pffffftttt.

It's happened briefly in the past, and I suspected the stock Victor argon regulator. It seemed to be fixed by running the regulator through the travel range and back to 25 cfh. Argon bottle started at 2200 psi, now down to about 1000 psi. I got into the habit of backing the regulator completely off when I am done welding, and closing the bottle valve, worried maybe this crappy reg was getting sticky.

I'm at my welding table in enclosed space, no sources of moving air other than my mouth-breathing.

I'm was thinking 1) Bad regulator, or 2) contaminated argon, or 3) faulty GSV in the Thermal Arc, 4) sucking air at some point in the torch plumbing, UNTIL I hooked up the TA 26 torch that came with my welder to test. It seems to have no issues, though testing hasn't been that scientific. Switched back to the CK9 and have erratic shielding again.

I've swapped back and forth between my Furick BBW and the CK Gas Saver large lens/cup, and even the stock #5 the CK9 came with. I reduced gas CFH to 20 for that test.

Any ideas? This setup has been pretty reliable for a few months since the initial regulator issue (I think) so seemingly spontaneous issues are troubling. I did order a Harris flowmeter to swap out for the stock Victor as another troubleshooting tactic.

Thanks

EDIT: Tonight I tried snugging up the knurled gas fittings in the torch end and inside the DINSE connector. Then I bumped the CFH to 32 (gas lens) and it seems to be fixed. Maybe the regulator is working but inaccurate. ?

[Oscar]

Have you verified the flow at the tig torch cup with a flow meter checker thing? This way you can compare it to what your regulator at the tank is reading and you'll know for sure.

[MFleet]

I purchased a profax gas flow tester part# 50020 for ~$10 and I find myself using it more than I thought I would. It has a cfh scale and it agrees with the readings on a smith flow meter. The only other tester that I found with a cfh scale is sold by CK. More expensive, but the mouth appears larger. The absolute max cup size for the profax is a #15.

22 cfh seemed to be more than enough for 1" of stickout on a standard extra large lens. I've read of higher flows with larger custom cups, etc.

The back cap and o-ring would be another thing to check.

[cj737]

This may sound obscure, but, by chance do you have a magnet nearby holding your work? That can really screw up your arc and can be “forgotten” or overlooked. It produces the same reactions you’re describing.

[tungstendipper]

Have you checked for any air leakage around your O ring on the glass lens? If that #12 cup gets bumped it can cause a leak around the o ring.

[Stringfellow]

Thanks all for the replies. Thought I had it sorted out so I kinda forgot about this thread, but I'm afraid the issues are still not resolved. I think gas flow is still the big issue. I like the idea of the flow tester to attach to the torch.

My Furick BBW recommends 25-30 CFH, and I toyed with higher and lower but I'm still getting spontaneous loss of shielding.

Yes, I have some triangle magnets on my welding table. I'll try removing them. They have never been an issue before.

I've wondered about the O-ring holding the cup. The 45V44 lens has a flat wrench surface machined into the brass, and that's where the O-ring goes. It seems to fit tight enough, but I can't be sure. The air leak troubleshooting is just elimination method I guess. I could put some soapy water at that junction I suppose. Water + electrified stuff though?

[ignatz200]

Be sure to check your back cap on the torch head. Sometimes the thing can leak. I had that problem once. I had just purchased a new medium-size back cap. For some reason the O-ring groove in the thing had been machined off-center so that a whisper of air could get sucked in. That really screwed up my weld beads until I figured it out.

[nelson]

This may sound obscure, but, by chance do you have a magnet nearby holding your work? That can really screw up your arc and can be “forgotten” or overlooked. It produces the same reactions you’re describing.

Can magnetized workpieces or fixturing cause this? I've not heard much of this.

[MFleet]

The air leak troubleshooting is just elimination method I guess. I could put some soapy water at that junction I suppose. Water + electrified stuff though?

When I tested my torch, I had the machine on dc, amps all the way down, high frequency start off. The pre/post flows set to max. Naturally, you want the ground clamp far away from everything and lay the torch on wood. I have a pedal, so there was no need to touch anything while triggering the gas valve. I used a small acid brush to apply the soapy water without making a mess.