Brown dust on side of steel TIG weld

[johnnymg]

Greets

Sorry for the newbie questions again but what do you think is causing this brown discoloration/dust? I have the 210 set up on DCEN and have tried low-high Ar (100%) gas flow. I have 3 sec of pre flow and 5 sec of post flow. The discoloration seems to track the angle of the TIG torch. i.e. the contamination is mostly in the direction of the gas flow. I was using a 3/32" 1.5% lanthanated electrode. Amps were set at 50. I did grind the metal but didn't wash it down with acetone. I'll get some acetone tomorrow.

The plasma looked OK/stable but I have zero experience with TIG welding so I can only compare to what I've seen on videos.

Attachment 10528

I'm SURE there are other issues with the set up but I thought I'd start with this funky contamination issue. Bad gas or bad setup/operator???

cheers
JohnG

[zoama]

Looks like poor gas coverage. You need totally clean metal with no breeze or drafts and proper torch angle. Turn your preflow down to less than 1 second and the post flow up to around 7. A picture of the torch setup would also help.
What was your gas flow setting ?

[johnnymg]

Looks like poor gas coverage. You need totally clean metal with no breeze or drafts and proper torch angle. Turn your preflow down to less than 1 second and the post flow up to around 7. A picture of the torch setup would also help.
What was your gas flow setting ?

I ran the Ar from 5-20 LPM. Didn't seem to make any difference.

Here are a couple pics of the setup. The tungsten electrode has some blackish "hair" on it.


regards
JohnG

[Rambozo]

I ran the Ar from 5-20 LPM. Didn't seem to make any difference.

Here are a couple pics of the setup. The tungsten electrode has some blackish "hair" on it.

By any chance, did you touch the molten puddle with the tungsten? You would see a greenish flash and get results that look like that. You need to grind your tungsten clean after any steel contamination.

[johnnymg]

By any chance, did you touch the molten puddle with the tungsten? You would see a greenish flash and get results that look like that. You need to grind your tungsten clean after any steel contamination.

Yes, I the tungsten did touch once. I'll give this another try Tues afternoon after I get some acetone. Besides the tungsten getting contaminated, is it possible the gas could also be contaminated? Seems like I was getting this funky "soot" before the tungsten contact.

regards
JohnG

[Rambozo]

Yes, I the tungsten did touch once. I'll give this another try Tues afternoon after I get some acetone. Besides the tungsten getting contaminated, is it possible the gas could also be contaminated? Seems like I was getting this funky "soot" before the tungsten contact.

Anything is possible, but it is pretty rare to get bad gas. First I would check over your torch for air leaks, especially around the back cap o-ring. That can suck air into your argon stream. TIG does take some practice. Acetone is kinda over the top for steel, but if you are not sure about any oil or grease it can't hurt to wipe it down. Remember to re grind your tungsten any time you contaminate it. Also keep your torch angle as close to 90° as you can. Also hold the torch still at the end of the weld while the post flow is going, to shield the end of the weld while it cools.

[joshuab]

Contaminated or not, that electrode is ready to be ground! Grind 'em on both ends so you can weld twice as long--but be careful. If it balls up on one end and you pull it out the front of the torch, then stick it back in and it balls up the other end, you can't get it out without cutting it.

[DaveO]

Grind 'em on both ends so you can weld twice as long

A fine idea as long as you don't rely on the color code to know what type of tungsten you're using!

[joshuab]

A fine idea as long as you don't rely on the color code to know what type of tungsten you're using!

That's totally true! I only use 2% Lanthanated, so it's not an issue.

[johnnymg]

WOHOOOOO ~~~~~~~~~
THANKS for all of the suggestions ~~~~

Here's how it went:
1.) ground tungsten and kept all previous HW/settings the same (3/32" tung, 10+ LPM AR flow, and #6 cup) ==> major arc instability and brown ugly contamination
2.) raised/lowered AR flow rate (and finally read manual). Ended up at 5 LPM flow rate (for steel). Major arc instability went away but still had brown ugliness and arc was still not totally "right". i.e. arc wass somewhat spitty
3.) As a WAG I changed the ceramic cup from the #6 I was using to a #5: ===> Super stable arc now and NO brown ugliness. Yehaaaaaaaa!

OK, I'm still "on the beach" but I'm no longer getting beat up by the shore break! Now, on to actually trying to dab some filler rod.

BTW, the 210 is awesome!

Thanks again for all of the help
JohnG

[Gman]

Is this 100% argon?

[johnnymg]

Is this 100% argon?

Yes, 100% Ar. What I'm thinking now is that there was major turbulence in the cup which caused the arc instability and 'brown soot' contamination.

cheers
JohnG

[zoama]

Sounds like the #6 cup wasn't seated correctly and let air mix with your gas. Too much gas flow can cause turbulence and draw air into the gas stream also, 6 - 9 lpm is the range you'll use most.

[joshuab]

Glad you got it sorted out. As Zoama585 pointed out, 5 lpm is going to be a little low for some positions and joints--e.g. an inside corner in the flat position, probably okay, because the joint will trap the gas and collect it. Flat position, lap or butt joint, I have found more like 6-7 lpm is required. And of course something like a thin outside corner is going to require more, and may even require some kind of backing plate to help collect the argon. Sometimes I feel stingy and try to knock my argon down a smidge, but usually it causes problems and it's not worth it. I mostly leave the flow-meter set at 7 lpm, and that does the trick for everything I commonly do. I may be using up 1-2 lpm more than I strictly need to, but I'm okay with that if it means I'm not constantly fiddling with the dial after having a problem with my weld.

And also, in case it's not obvious, you read a ball-type flow-meter from the center of the ball, and the flow-meter must be straight up-and-down to read correctly.

[johnnymg]

Glad you got it sorted out. As Zoama585 pointed out, 5 lpm is going to be a little low for some positions and joints--e.g. an inside corner in the flat position, probably okay, because the joint will trap the gas and collect it. Flat position, lap or butt joint, I have found more like 6-7 lpm is required. And of course something like a thin outside corner is going to require more, and may even require some kind of backing plate to help collect the argon. Sometimes I feel stingy and try to knock my argon down a smidge, but usually it causes problems and it's not worth it. I mostly leave the flow-meter set at 7 lpm, and that does the trick for everything I commonly do. I may be using up 1-2 lpm more than I strictly need to, but I'm okay with that if it means I'm not constantly fiddling with the dial after having a problem with my weld.

And also, in case it's not obvious, you read a ball-type flow-meter from the center of the ball, and the flow-meter must be straight up-and-down to read correctly.

Thanks for the tips on the flowmeter. I think I was using the top of the ball so the flow was probably on the low side. I'm on the step portion of the learning curve so I'll be asking 'obvious' questions for a while.

cheers
JohnG

[joshuab]

Thanks for the tips on the flowmeter. I think I was using the top of the ball so the flow was probably on the low side. I'm on the step portion of the learning curve so I'll be asking 'obvious' questions for a while.

No worries. I had to look it up.

[sportbike]

I use a "gas lens" on mine most of teh time. It has a screen diffuser inside to increase gas coverage.

[johnnymg]

I use a "gas lens" on mine most of teh time. It has a screen diffuser inside to increase gas coverage.

From what I've read that's a good way to minimize gas turbulence. I'm in the process of collecting parts for a CK water cooled torch with the "gas saver" screen diffuser.

Here's a pic of the pyrex cup with the screen diffuser installed.


cheers
JohnG

[joshuab]

From what I've read that's a good way to minimize gas turbulence. I'm in the process of collecting parts for a CK water cooled torch with the "gas saver" screen diffuser.

Those Pyrex cups sure are sexy, but man they're not cheap. Whatever you do, don't accidentally pull your torch's lead and knock it on the floor and break the cup. Oops.

[johnnymg]

Those Pyrex cups sure are sexy, but man they're not cheap. Whatever you do, don't accidentally pull your torch's lead and knock it on the floor and break the cup. Oops.

Indeed, thanks for the reminder on dropping the torch off the workbench.

I will say it was a real "aha" moment when the arc was stable and I could see the puddle as I moved the torch about. Perhaps 'no big deal' for you vets but after struggling for a while a real cool sight for this TIG newbie.

cheers
JohnG