Problems with TIG on Mild Steel

[eKretz]

I usually snap 'em off too, but I nick/score 'em all the way 'round with a diamond wheel first. Never have any problems with cracking. Usually don't need to do that unless I have a major dip, which is pretty rare.

 

[604Pook]

I have had one bad bottle of Argon in 20+ years of tig welding, and luckily it was in the last 5 years, so I had a very good idea it had nothing to do with me, and happened right after the bottle was changed mid job.

The new large fancy gas lense shouldn't make any difference in the issue your having, and really is only needed when doing tube work or like other said some stainless type welding. Its really just a hyped up thing thanks to instagram.

this guy has lots of good tig welding videos. I would watch some.

 

[Cyclotronguy]

The soot is evidence of carbon that has not been oxidized to CO2 or CO. Seems like you have carbon contamination from somewhere, and the reasonable source is the gas bottle. Is there a chance some fuel gas (acetylene, propane) got pushed into it during a different use?

I was gong to say that was either high carbon or leaded steel.

 

[David_M]

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.

The setting *lift start* instead of *high-frequency start* might be a good idea for the above test.

 

[eKretz]

The setting *lift start* instead of *high-frequency start* might be a good idea for the above test.

Shouldn't matter for most decent meters. DC circuit is just averaging, and we're not concerned with accuracy, just polarity.

 

[G-ManBart]

Edited for grammar.

As a self-professed grammar nazi I love a good edit for grammar!

 

[bjfurman]

2024-03-09 update:

I looked into three things suggested by some of you:

1. Verified that TIG is running DCEN. On 1/4 inch machine setting (190A), my DMM measured about 12 - 14 V from work to tungsten (positive work, negative tungsten)
2. Tried a stubby gas lens (#7 size, 3/32 lanthanated, running 8 LPM 'argon' ) instead of the standard #7 cup that came with the rig
3. Swapped my supposed 'argon' gas line with argon-CO2 from the MIG side of the rig just to see what would result (picture is below)

From right to left in the picture:

1. Result from my last post (on 1/4 inch setting, 1/4 in HR well-cleaned (flap disk shiny, multiple acetone wipes), 8 LPM argon flow)
2. Result from #7 stubby gas lens (same settings)
3. Result with #7 stubby but with Ar-CO2 instead of my supposed pure argon (same settings)

My conclusion (like some of you reached earlier, but I wanted to rule out everything else first) is that the supposed pure argon I have is anything but. It's interesting that result with Ar-C02 is slightly 'better' than with my argon attempt. There is hardly any of the grotesque porosity in the Ar-CO2 bead. Both show lots of brown crud, which one would expect with the wrong gas or gas with a contaminant.

I will be taking the Ar bottle back to the supplier next week. I'll report back on what happens when I get it set up.

Thanks for all your input to help me figure out what is going on.

 

[BT Fabrication]

2024-03-09 update:

I looked into three things suggested by some of you:

1. Verified that TIG is running DCEN. On 1/4 inch machine setting (190A), my DMM measured about 12 - 14 V from work to tungsten (positive work, negative tungsten)
2. Tried a stubby gas lens (#7 size, 3/32 lanthanated, running 8 LPM 'argon' ) instead of the standard #7 cup that came with the rig
3. Swapped my supposed 'argon' gas line with argon-CO2 from the MIG side of the rig just to see what would result (picture is below)

From right to left in the picture:

1. Result from my last post (on 1/4 inch setting, 1/4 in HR well-cleaned (flap disk shiny, multiple acetone wipes), 8 LPM argon flow)
2. Result from #7 stubby gas lens (same settings)
3. Result with #7 stubby but with Ar-CO2 instead of my supposed pure argon (same settings)

My conclusion (like some of you reached earlier, but I wanted to rule out everything else first) is that the supposed pure argon I have is anything but. It's interesting that result with Ar-C02 is slightly 'better' than with my argon attempt. There is hardly any of the grotesque porosity in the Ar-CO2 bead. Both show lots of brown crud, which one would expect with the wrong gas or gas with a contaminant.

I will be taking the Ar bottle back to the supplier next week. I'll report back on what happens when I get it set up.

Thanks for all your input to help me figure out what is going on.

that definitely looks like a gas issue. just had one here like that, gas lens was worn out,/dirty enough that the speed was sucking air into the weld gas doing the same thing. it bubbles and blows up as you weld and is a definite sign of contamination.

 

[bjfurman]

Finally, SUCCESS!!!

I took the 'argon' bottle back to the supplier today, and they were easy about swapping it for a new bottle. They looked a bit incredulous that it would be contaminated, and one of the guys there said he had never seen a contaminated bottle in all the time he's worked there... Before I brought the original bottle back, I tried just striking an arc on a 1/4 inch coupon of 6061-T6 to see what it would look like, since all the other 'experiments' described above were all on HR or CR low-carbon steel. I'm including that picture below. It was nasty! I brought the coupon with me to show them, just in case they needed 'proof'.

With the new argon bottle, I tried a few no-filler passes and a few with ER5356 Al rod. The difference between what I had experienced with the old bottle and the new bottle was like night and day! Amazing! The arc was stable (no frothy splashing), a nice controlled puddle formed, there were no volcanic streamer sparks, the bead and area around it were clean (no soot), it even sounded different, a nice, satisfying buzz. So, yes, one can get a contaminated argon bottle, even from a reputable supplier.

So, I'm on first base now! Thanks for all your help to figure out what was going on. Now it's time to burn some rod and get some practice...

 

[eKretz]

Figgered that was gonna be it. Good that you got it straightened out easily.

 

[Trboatworks]

It may have been a lose gas fitting somewhere which was inadvertently resolved when you switched out the bottle.
I have had a few similar issues over the years and it was always my setup not the gas bottle.

One bit of input- when setup well tig just works and the issue of perfectly clean surfaces type of gas lens etc just are not going to kill the weld.
A butcher approach still works and you can see the oils burning off, rust floating around or oxide debris all through aluminum puddles but it still works.
If it just fails to weld it’s no gas or lose gas fittings or something else just basically wrong with the setup and not the fine details.

 

[Freedommachine]

Finally, SUCCESS!!!

I took the 'argon' bottle back to the supplier today, and they were easy about swapping it for a new bottle. They looked a bit incredulous that it would be contaminated, and one of the guys there said he had never seen a contaminated bottle in all the time he's worked there... Before I brought the original bottle back, I tried just striking an arc on a 1/4 inch coupon of 6061-T6 to see what it would look like, since all the other 'experiments' described above were all on HR or CR low-carbon steel. I'm including that picture below. It was nasty! I brought the coupon with me to show them, just in case they needed 'proof'.

With the new argon bottle, I tried a few no-filler passes and a few with ER5356 Al rod. The difference between what I had experienced with the old bottle and the new bottle was like night and day! Amazing! The arc was stable (no frothy splashing), a nice controlled puddle formed, there were no volcanic streamer sparks, the bead and area around it were clean (no soot), it even sounded different, a nice, satisfying buzz. So, yes, one can get a contaminated argon bottle, even from a reputable supplier.

So, I'm on first base now! Thanks for all your help to figure out what was going on. Now it's time to burn some rod and get some practice...

Good deal! Thank you for carrying this thread to completion, most get left without showing a solution.

 

[bjfurman]

@Trboatworks, interesting idea... A little bit of added detail in my situation that makes me think that it was *not* due to a loose fitting, I had done the soapy water check from torch, feedline, machine output, machine input, feedline to the regulator, regulator fittings, all the way to the original bottle outlet (as mentioned in this thread back a page or two). I went ahead and disconnected the regulator and put the cap back on the bottle to get it ready to take back to the supplier, when I saw a post by someone who said that if you were having issues with soot and terrible welding TIG on steel that you should try running a bead on aluminum. If that came out shiny and clear, then it would not have been the shield gas causing the problem. Soooo, I put the regulator and fittings back on the bottle and tried a 6061 coupon with the original bottle. It produced the sooty start I showed in my earlier post. Taking off and putting the regulator back on the old bottle was the only thing that changed in that last attempt to sort out the issue, and it *still* produced the same outrageously bad start with soot and volcanic arc/puddle that I had seen from the get-go with trying TIG on my rig and the original argon bottle. The night and day difference with the new bottle from the first attempt leads me to believe it was contamination in the first bottle.

 

[G-ManBart]

It may have been a lose(loose) gas fitting somewhere which was inadvertently resolved when you switched out the bottle.
I have had a few similar issues over the years and it was always my setup not the gas bottle.

This is implausible, at best. The only thing changing when you swap bottles is the main bottle to flow meter/regulator connection. That's at 2000psi (give or take on a full bottle) and it's not going to let anything into the system so a leak there wouldn't cause contamination in the first place.

Further, he tested all the fittings with soapy water, so a leak is extremely unlikely. He swapped bottles and magically the welds look normal...that's contaminated gas.

As I mentioned above, a friend owned the local welding shop where I get most of my bottles. She told me she saw contaminated bottles happen with some frequency, but almost always when a bottle was switched from one gas to another. I've had contaminated bottles that I'm 100% certain were bad...swap back and forth, with no other changes, and get normal welds with one, and contaminated, sooty crap with the other. It happens.

 

[eKretz]

I've definitely had a handful of contaminated bottles over the years. And I *always* bleed/purge lines when switching bottles.

 

[Trboatworks]

This is implausible, at best. The only thing changing when you swap bottles is the main bottle to flow meter/regulator connection. That's at 2000psi (give or take on a full bottle) and it's not going to let anything into the system so a leak there wouldn't cause contamination in the first place.

Further, he tested all the fittings with soapy water, so a leak is extremely unlikely. He swapped bottles and magically the welds look normal...that's contaminated gas.

What?
I’ve had it happen in my shop and have to date never seen a bad bottle of gas.
The last time I saw a problem a low pressure fitting on the welder had developed a leak and was a bear to chase down.
Does not show leak with soapy water due to being charged with a breath of pressure just when welding and it seems more letting air in than gas out..
In my case just handling the torch lines would stop the problem for a bit so pulling a bottle and generally Messing with things can do so.
It does sound like he has it sorted.

I hadn’t seen his note in the thread on having tested fittings with soap.
I’ll repeat- a well setup system just runs and these threads are always trying to chase the nth degree of tungsten torch etc.
In my experience there is plenty of wiggle room in these things and it takes some greater fault to blow up results ( like a bad bottle eh)
I’m often out on boats in the field tacking work with the little Maxstar in a good breeze- you can get away with a lot..

 

[MrWhoopee]

I had this same problem, like I had suddenly forgotten how to weld. I could feel the puff of gas when I stepped on the pedal. Blamed it on bad gas, LWS replaced it. Same problem. Discovered that the gas hose had been damaged right where it exited the front of the welder. Must have bumped it with something. It was split just enough that it allowed some flow but not enough. Got rid of the ultra-flexible lead and got a more durable, less flexible one. I can weld again (well, sort of)..

 

[akjeff]

Glad you got it figured out! I have to say my experience is like that of Trboatworks. I've been fortunate, and have never had a bad bottle of gas in 40 years of MIG/10 years of TIG welding. Have had plenty of other issues, but all were either me, or an equipment issue. I'd think if I had a gas supplier that said bad/contaminated gas is "pretty common", I'd look for a new gas supplier.

 

[G-ManBart]

I'd think if I had a gas supplier that said bad/contaminated gas is "pretty common", I'd look for a new gas supplier.

I didn't say "pretty common" I said "with some frequency". I don't know if that was two times a year or two times a month, but they had hundreds of bottles lined up coming and going every week.

I also said the owner of the shop said it happens mostly when they change the gas in a bottle because it has to be evacuated more carefully. The guys they pay to do that aren't exactly rocket scientists and mistakes happen.

I'm far from the only one who's experienced contaminated bottles, even in this thread, and if you go on a welding forum it's beyond an established fact that it happens.

I have bottles from three different suppliers and I've gotten contaminated bottles from two of them. I don't get many bottles from the second place, but when I took back the contaminated bottle with a test piece showing results from a good bottle and the bad bottle they didn't even blink and said "it happens". They swapped my bottle with no questions asked. If it was unheard of I think they would have had questions.

Just because it hasn't happened to you doesn't mean it can't happen.

 

[akjeff]

I didn't say "pretty common" I said "with some frequency". I don't know if that was two times a year or two times a month, but they had hundreds of bottles lined up coming and going every week.

I also said the owner of the shop said it happens mostly when they change the gas in a bottle because it has to be evacuated more carefully. The guys they pay to do that aren't exactly rocket scientists and mistakes happen.

I'm far from the only one who's experienced contaminated bottles, even in this thread, and if you go on a welding forum it's beyond an established fact that it happens.

I have bottles from three different suppliers and I've gotten contaminated bottles from two of them. I don't get many bottles from the second place, but when I took back the contaminated bottle with a test piece showing results from a good bottle and the bad bottle they didn't even blink and said "it happens". They swapped my bottle with no questions asked. If it was unheard of I think they would have had questions.

Just because it hasn't happened to you doesn't mean it can't happen.

I didn't say it can't or doesn't happen, I just said I've been fortunate, and it hasn't happened to me. As far as the "pretty common" or "with some frequency", that's on me. Either would concern me, as far as vendors go. Maybe it's a local/regional thing. At any rate, glad the OP has his problem solved. Of course, now I'll probably end up with a bottle of bad gas, next time I swap tanks!