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Problems with TIG on Mild Steel

I had a problem like this and a Miller field person came to my place.
It was a clogged hole for the shield gas on the back of the machine. He must have seen that before.

What regulator is on your tank? Open up the connections and try to see the light of day. Might be a partial clog. I would use toothpicks or fine solid wire.
 
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I'll second what Rons said. Miller has field reps that your dealer can put you in touch with. I had a problem updating firmware on my machine and it stopped working. Every time I started it I got an error when I started TIG. The field rep was familiar with the issue and solved it after a quick conversation.
 
Too much stickout without a gas lens. Try 1/8". The cup should be so close that it's almost dragging in the puddle. Also try a No6 cup instead of the No7.

Did you try retracting the tungsten a bit then using the gas-test function of the welder (if it's got one) to check for leaks by putting your thumb over the cup? Don't try this on an HF start welder without a gas-test function, it'll hurt!

20240118_191116.jpg20240119_110552.jpg

#5 cup
1/16 purple band tungsten
.35" stick out
15 cfm gas flow
Yes, that is 2 hose clamps and a mag base holding the torch 🙃.

IIRC, I saw a YouTube video from one of the welding channels and the fella stated that the cup # has a rough correlation to tungsten stick out in 16th's of an inch. #5 cup = 5/16... #7 cup = 7/16, ect. I am not a professional welder by any means but that is the rule I stick to and it works pretty well.

Back to the op's issue; those welds look real odd. Would a gas issue cause that crater at the end of the weld? The puddles do not look extremely porous, just...weird. The soot definitely seems like a gas issue though.

@bjfurman please keep us updated on this as you work through it, I am curious to know what would cause the issues you are experiencing.
 
I don't know how this has not been pointed out, if your info is correct - your issue is your shielding gas. Your settings are WAY too low. You should be running around 12+ CFM (cubic FEET per minute), not 15 LITERS per minute. Up that gas flow!!! Use a sharp tungsten and clean metal, and it doesn't even need to be that clean. Also if you're having a clean weld with a bad puddle you might try a different tungsten. Old transformer welders work great with thoriated (red) tungsten but newer inverter machines work well with different types like the lanthanated.

Regarding gas lenses, I was as happy to stop using them as I was to start using them. They waste a ton of gas for no measurable benefit on steel. If you're welding sanitary stainless and titanium, probably a good move.
 
I don't know how this has not been pointed out, if your info is correct - your issue is your shielding gas. Your settings are WAY too low. You should be running around 12+ CFM (cubic FEET per minute), not 15 LITERS per minute. Up that gas flow!!! Use a sharp tungsten and clean metal, and it doesn't even need to be that clean. Also if you're having a clean weld with a bad puddle you might try a different tungsten. Old transformer welders work great with thoriated (red) tungsten but newer inverter machines work well with different types like the lanthanated.

Regarding gas lenses, I was as happy to stop using them as I was to start using them. They waste a ton of gas for no measurable benefit on steel. If you're welding sanitary stainless and titanium, probably a good move.

Uh, no. Shielding gas is usually spec'd in cubic feet per HOUR. He's fine. I usually TIG at 15-20 CFH, which is 7-9.5 LPM
 
Uh, no. Shielding gas is usually spec'd in cubic feet per HOUR. He's fine. I usually TIG at 15-20 CFH, which is 7-9.5 LPM

Well now I feel dumb, I misspoke in the numbers I provided as well. This whole time I've been thinking that the black #'s on my flow meter were cubic feet per something... looking at it closer, it does clearly say L/min! :sulk:
My apologies everyone. In my defense, Harris did make the black line on the tank pressure gage PSI.

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Uh, no. Shielding gas is usually spec'd in cubic feet per HOUR. He's fine. I usually TIG at 15-20 CFH, which is 7-9.5 LPM

Haha dude I've been staring at compressors a little too much this week, you're spot on!

It does look like a shielding gas issue though. If the gas is around 7+ LPM, that should be right in the range for a regular cup. It might be bad gas in the bottle or a leak somewhere in the line that's dropping the flow too much - that would be easy to check, you could crank the shielding gas way up and try a weld and see what it does.
 
Well now I feel dumb, I misspoke in the numbers I provided as well. This whole time I've been thinking that the black #'s on my flow meter were cubic feet per something... looking at it closer, it does clearly say L/min! :sulk:
My apologies everyone. In my defense, Harris did make the black line on the tank pressure gage PSI.

View attachment 430931

Gotta pay attention to detail, haha. Anyways if you are running 15 LPM you're using a lot of gas. Probably can get away with almost half that flow rate.
 
2024-03-03 update on the debug progress:

I looked for leaks in the argon supply hose and fittings using soapy water. Some bubbles appeared at the nut from the regulator to the tank (see the picture). Those went away with a little tightening of the fitting. No leaks were found from there all the way to the torch body. There was some slight bubbling at the interface between the white (teflon?) bushing and the black rubber that surrounds the torch body (see the picture). The bushing has a groove that engages a circular ridge of the black rubber that surrounds the torch. There is nothing that can be tightened in that arrangement, so I don't know what can be done about it. I'm thinking that a leak there will not cause a problem with sucking *in* room air, since with argon in the line there will be sufficient back pressure to keep air from coming in (just a little argon will leak out). Or maybe I should put some vinyl tape over it to reduce it further? The leakage volume seems to be orders of magnitude smaller than the shielding flow. Is it of concern?

I put a balloon over the torch tip to verify that there was argon flow and to see if I could approximately measure the volume flow rate to compare to what the regulator reads. The YouTube video shows the test:
The regulator indicates about 8 LPM, and my rough calculations using the balloon volume says it was about 12 LPM.

I tried a few beads on *well cleaned* 1/4 in. HR, first on 3/16 setting and no filler, then on 1/4 setting with Linde ProStar ER70S-2 3/32 in. filler rod. I shot video of these attempts:

--> 3/16 in. setting no filler YouTube:
--> 1/4 in. setting with Linde ProStar ER70S-2 3/32 in. filler rod YouTube:

What do you see in the videos or the weld results (besides them being lousy)?

The puddle still seems very 'splashy' compared to what I see on every tutorial on TIG in YouTube. Is the argon flow too high? I just got a gas lens kit, so that will be one of the next things I'll try.

I have not found a way to test the polarity. As I understand the Multimatic 220 AC/DC is supposed to set the polarity automatically. How can I check the polarity?

The periphery of the bead shows lots of brown crud. Is that to be expected if the argon is not contaminated? From the balloon test I *know* that I am getting good gas flow. It is still a question in my mind as to whether the gas is contaminated or not. I have yet to swap cylinders with Ar-CO2 (just to see what the welds look like with the wrong gas) or get a new bottle of argon.

Thanks for your help!!!
 

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Video record striking an arc on stainless steel. That would confirm that your argon is not pure (at least by the time it reaches the arc). No dipping the tungsten, though.

There could be issues with the steel you are using. Look up fully-killed, semi-killed, and rimmed steel.

E70-S2 contains triple deoxidizers to help with oxygen-containing steel. Still, I have seen cases where it can't fully control the porosity (especially if it is added to the puddle inconsistently or improperly).
 
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Change the bottle already. And are you certain you're not dipping the tungsten? It sure looks like it might have some melted steel on it in at least one of those vids. You can probably check polarity with a multimeter. Put the neg lead on the tungsten and the pos lead on the welder's ground lead and see what you get when you hit the pedal. It should be a positive number. If you get a negative number you've got improper polarity.
 
In forty some years, I’ve never seen bottled gas be contaminated, however if I was having your kinda troubles, I’d change the bottle and check polarity.
We have a few choices on gas supply around here. I have used most of them at one time or another, never seen it?
 
You need to cut off the end of your electrode and give it a fresh point on clean tungsten. You've definitely got some dipping in the puddle going on there. It should look like the picture attached here, and yes I've run a bead with it and it still looks fresh, Welding steel should not cause the point to ball up like yours did. That happens on aluminum( or welding steel using the wrong polarity, or AC ). If you dip your tungsten in the puddle( or hit it with your filler rod ), stop immediately and grind a new point on as far back as you need to, to be on virgin tungsten. If there's even a tiny bit of contamination above the point, it'll re-contaminate the point as soon as you light up.
IMG_2028.JPG
 
In forty some years, I’ve never seen bottled gas be contaminated, however if I was having your kinda troubles, I’d change the bottle and check polarity.
We have a few choices on gas supply around here. I have used most of them at one time or another, never seen it?
I've had two or three contaminated bottles in the past ten years. I'm friends with the owner of the closest welding shop/gas supplier and they told me they see it pretty regularly, but almost always when a bottle gets changed from an ArgonCo2 blend to straight Argon. The last time I had it happen they told me they had two or three bottles from one batch, so it was probably somebody new not sucking the bottles down completely before filling them.

The results looked exactly like what the OP is seeing.
 
Forgot to add; when/if you shorten your electrode.....do not just nick it with a grinder and snap it off! Grind it all the way through on the corner of a grinding wheel, or with a diamond disc on Dremel, etc.. Bottom line is, cut it off, don't break it. You may get away with it, or you may cause tiny cracks in the tungsten that won't get ground away when you sharpen it, and then they will drive you nuts.
 
You need to cut off the end of your electrode and give it a fresh point on clean tungsten. You've definitely got some dipping in the puddle going on there. It should look like the picture attached here, and yes I've run a bead with it and it still looks fresh, Welding steel should not cause the point to ball up like yours did. That happens on aluminum( or welding steel using the wrong polarity, or AC ). If you dip your tungsten in the puddle( or hit it with your filler rod ), stop immediately and grind a new point on as far back as you need to, to be on virgin tungsten. If there's even a tiny bit of contamination above the point, it'll re-contaminate the point as soon as you light up.

I almost never cutt off the end of the electrode and have zero issues. I've got a belt grinder dedicated to nothing but tungsten sharpening. I use one side to get the nasty stuff off, then finish on the other side for the final cleanup and sharpening. I've been doing that for years without a problem.

Welding steel with contaminated gas (or dirty metal) that causes the spitting and popping he's showing in the videos will cause some of the parent metal to migrate to the tungsten making it look like it's balling or like you've dipped the tungsten.
 
I almost never cutt off the end of the electrode and have zero issues. I've got a belt grinder dedicated to nothing but tungsten sharpening. I use one side to get the nasty stuff off, then finish on the other side for the final cleanup and sharpening. I've been doing that for years without a problem.

Welding steel with contaminated gas (or dirty metal) that causes the spitting and popping he's showing in the videos will cause some of the parent metal to migrate to the tungsten making it look like it's balling or like you've dipped the tungsten.
But you do, as you said, "get the nasty stuff off" which was really my point. Cut it off, grind it off, doesn't matter. What does matter is not leaving contamination above your new sharpened point. The OP looks like he's new at this, and I was just trying to correct the obviously contaminated tungsten, before he went any further.

Edited for grammar.
 
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