Am I a TIG Welder Yet?

Welding Techniques, Theory, Machines and Questions.

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SteveHGraham
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Am I a TIG Welder Yet?

Post by SteveHGraham » Wed May 03, 2017 6:20 pm

My aluminum adventures are not going well at all. I keep finding the aluminum blows out before it forms a puddle, and I get black stuff around the weld. Sometimes the molten metal turns into a strange black foam. I managed to create a couple of joints which were technically welds, but they were nasty to look at.

Today I went back to steel, figuring that since aluminum is harder to weld than steel, my aluminum failures might have made me a better steel welder. Turned out that was correct.

I switched to a 2% lanthanated tungsten, and while I did not expect much difference, it seems more controllable than E3. I managed to create something that more or less resembles a weld. The tungsten balled up in a hurry, but it did the job.

My big problems with steel seem to be bad wire feeding, bad timing, and failure to hold the torch close to the joint. Today I started practicing with a dead torch, just counting out the timing and pretending to form a puddle, dip the rod, and move. I believe it's a waltz. It seems to help a lot, but I guess it will be a few days before it sinks in. There was a big gap in the weld in on the other side of this thing because my timing got mixed up.

Anyway, I am now capable of joining two pieces of metal, as long as the joint is not really, really important, and it doesn't have to be where anyone can see it.
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05 03 17 tig practice 125 thou iron lap small.jpg
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GlennW
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Re: Am I a TIG Welder Yet?

Post by GlennW » Wed May 03, 2017 8:18 pm

For the aluminum, try more Argon (20cfh) and make sure you don't have a leak somewhere.

The tungsten balling up indicates the balance may be off, but that doesn't really coincide with the black in the weld. Try setting the balance to 35%-40% and see if that changes the balling. It should ball up a little, but nowhere near as much a pure tungsten does.

You might also try a different gas lens if you have one. It may be getting a bit plugged up from spatter.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

choprboy
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Re: Am I a TIG Welder Yet?

Post by choprboy » Thu May 04, 2017 12:51 am

The steel is looking better. The long weld is a bit more consistent, started off with not quite enough heat in the pool. About 1/4 of the way right to left the base metal had heated up and starting to look better, a bit of undercut but getting close. A little past the second half there got to be too much heat in the part, more undercutting and can see where you sped up/took larger steps to try and keep up. I would say, needs a bit more power in the start and the first couple steps, then back off to where you were, about half way across reduce the power a little bit more. Basically, try to race the heat front in the part and stay just behind the "wave" as it moves down the joint.

Tungsten should generally ball up when welding on AC (pure/green tip most definitely), it should be a clean ball, not have "tumors" or growths off the side. Some newer tungsten mixtures these days are designed to not ball much with inverter-based/high frequency machines though (I have an older 60Hz-only machine though).

The black foam would indicate contamination and poor cleaning action of the arc. Could be bad gas, contamination of the aluminum (oil/etc. in the pores), or you are running very high DCEN with little AC cleaning action. I would start by setting cleaning to 50% (straight 50% duty cycle wave) and see if it goes away.

Aluminum is hard to weld because there is very little difference between a solid surface and melting pool, particularly if there is contamination/a lot of aluminum oxide on the surface. It takes alot of heat to start and goes from what looks like a solid form to a molten blob that falls away in the blink of an eye. Thick sections (1/4" plate) are much easy to learn on as it has enough thermal mass to wick away in the excess heat and keep you from getting the molten pool too deep. Thin (16ga) takes a lot of practice before you can make something passable in my experience.

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SteveHGraham
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Re: Am I a TIG Welder Yet?

Post by SteveHGraham » Thu May 04, 2017 12:51 pm

Thanks for the comments.

I was using DC on steel. I hope no one thinks it was AC. I mean, it WAS AC for a few seconds, until I realized I had forgotten to switch back to DC. After that it was all DC.

The tungsten balled up on DC. I was welding 1/8" steel with max amps of 125. The gas was set at about 12.

The aluminum filler gave me problems yesterday. Something kept blowing it back up the rod, so I got blobs that had to be cut off. The metal was very clean, so I don't think the black mess I got was caused by dirt on the metal itself.

I like the 1/4" aluminum suggestion, although this machine only goes to 200 amps, so I suppose I should look for 3/8".
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10KPete
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Re: Am I a TIG Welder Yet?

Post by 10KPete » Thu May 04, 2017 1:03 pm

If the tungsten balled up on DC then you had the polarity basakwards!!

Pete
Just tryin'

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SteveHGraham
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Re: Am I a TIG Welder Yet?

Post by SteveHGraham » Thu May 04, 2017 1:13 pm

Holy cow. I'll bet that's exactly what happened. If there are more than two things to remember when I set up a tool, I am guaranteed to forget some of them.
Every hard-fried egg began life sunny-side up.

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GlennW
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Re: Am I a TIG Welder Yet?

Post by GlennW » Thu May 04, 2017 1:27 pm

Sorry, I misread and thought the Lanthanated tungsten was balling up on alum.
SteveHGraham wrote: If there are more than two things to remember when I set up a tool, I am guaranteed to forget some of them.
Sounds like my reading comprehension...
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!

choprboy
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Re: Am I a TIG Welder Yet?

Post by choprboy » Thu May 04, 2017 2:40 pm

Ah, yes... didn't quite understand that, thought it was balling and black under AC on the aluminum, then you did DC on the steel with a sharp point. As 10KPete said, if your balling on DC you most likely have polarity reversed. Normal TIG is DCEN and the majority of the arc heat goes into the part. One trick that i sometimes used (thin stock/heavy oxidation/odd materials) is to run DCEP TIG, most of the heat goes into the tungsten (which causes the tip balling or complete melting of the tungsten if not careful) but you get better heat control in thin parts and better cleaning action.

When welding aluminum on AC, you are combining putting heat in the part with DCEN and cleaning the oxide off the surface with DCEP. Ideally, you set the balance so that you have enough DCEP to clean the part, but the rest of the wave form is DCEN for maximum heat into the weld. You can then also change the frequency of the AC (if your machine is so equipped... stuck at 60Hz here). Higher frequencies help narrow the arc zone and provide more depth penetration. Miller has a pretty good explanation on it:
https://www.millerwelds.com/resources/a ... -frequency

You don't need a 200A machine to weld 1/4" aluminum, it just takes more/smaller passes to accomplish the same as a larger machine. My welder only goes to 180A, haven't done any in several months but I have welded 1/4" plate brackets to each other and 1/2"~1" blocks at 140~150A-ish. Only have a gas-cooled torch though, so it gets hot fast, to hot to run long without damage.

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10KPete
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Re: Am I a TIG Welder Yet?

Post by 10KPete » Thu May 04, 2017 2:54 pm

SteveHGraham wrote:Holy cow. I'll bet that's exactly what happened. If there are more than two things to remember when I set up a tool, I am guaranteed to forget some of them.
Well, waddaya expect from a beginner!! :P :P :P

Keep at it. Soon it will soak in and be 'natural'.

Pete
Just tryin'

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warmstrong1955
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Re: Am I a TIG Welder Yet?

Post by warmstrong1955 » Thu May 04, 2017 6:31 pm

Somethings you may want to try with aluminum Steve.....
Drop a size in tungsten. Smaller puddle, smaller bead, doesn't fall through so easily. It'll get you the knaack, and you can go bigger again after some playing. (Helped me)
Get some magnifiers. I use cheapy Walmart reading glasses. Much better than using my bifocals. Puddle is harder to see with aluminum,
Black around the bead....not enough argon, or crud and/or oxidation. I assume you are using a stainless brush for aluminum?
If you are getting spatter, you have some kind of contamination.
Crud, and especially oil, will give you an ugly black foam. I used to weld a lot of my motocross bike parts, including case halves.
A nasty one, was Cummins cast aluminum oil pans. They crack when they get old, and all you can do is grind out as best you can, clean, and weld a bit....and regrind, sharpen the tungsten, and go at it some more....repeat as required. The main crack is easy, but there were always little ones off the big one.....like lightening, and the oil would be in them.
Black around the weld, and porous foamy looking weld....oil....
Those things were a pain in the posterior....

:) Bill
Today's solutions are tomorrow's problems.

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SteveHGraham
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Re: Am I a TIG Welder Yet?

Post by SteveHGraham » Thu May 04, 2017 6:51 pm

I used a stainless brush on the aluminum, followed by acetone. Maybe I didn't get it as clean as I thought.

Thanks for the tungsten suggestion. That might actually get me somewhere.
Every hard-fried egg began life sunny-side up.

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warmstrong1955
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Re: Am I a TIG Welder Yet?

Post by warmstrong1955 » Thu May 04, 2017 7:13 pm

That's how to get 'er clean. I have a few brushes that are for aluminum only. Cleaning steel will crud them up, so I keep them separate.
And what Glenn said about the gas....and are you holding the torch more perpendicular?
You can get away with a lot of stuff with steel, that you can't with aluminum.

More often than not, I use 2% thoriated. Most of my work is stainless of some type. If I do much aluminum at all, I have some pure tungsten. (green tip)
I keep sizes from .040" to 1/8"....although I don't remember the last time I used any 1/8". If the material is thick enough for 1/8", I MIG it.

Lookin' at your pic, you are improving by the way.

Practice practice practice.
And if it's not workin' out right...try something different! May work....may not...but you can learn from it either way!

Good advice from all here!

:)
Bill
Today's solutions are tomorrow's problems.

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