[jonesk0668]

Just a note that I am a noobie at tig
I was trying to get some practice in yesterday on some 1/8" aluminum plate and just could not get a puddle and the arc was going everywhere. I checked my settings and all were correct. (125-140 amps on AC with 15 on the flow). I was using 2% thoriated 3/32, with 1/16 filler and a #8 cup. I noticed after several tries and re-checks that my bottle was a little on the low side. Down to about 20 on the gauge. The flow seemed ok...
Will that cause an unstable arc?

[MosquitoMoto]

Hi and welcome.

While I'm not qualified to comment on your gas (although I suspect you are indeed running a bit too low) you'd be better off with 2% Lanthanated or even zirconiated electrodes on aluminium, rather than Thoriated.


Kym

[Otto Nobedder]

Just a note that I am a noobie at tig
I was trying to get some practice in yesterday on some 1/8" aluminum plate and just could not get a puddle and the arc was going everywhere. I checked my settings and all were correct. (125-140 amps on AC with 15 on the flow). I was using 2% thoriated 3/32, with 1/16 filler and a #8 cup. I noticed after several tries and re-checks that my bottle was a little on the low side. Down to about 20 on the gauge. The flow seemed ok...
Will that cause an unstable arc?

Yes, this can cause issues. If there is any moisture at all in your gas, it will rear it's ugly head when the bottle's nearly done. I assume you've been using the same setup for a bit, in the same way, and the trouble is new? If so, the gas is very likely the culprit.

Welcome to the 'hood (pun intended).

Steve S

[WTFH]

If you have a gas issue your tungsten would be dark after it cooled down due to a lack of shielding. But with 140 amps you should have been able to form a puddle no problem even with bum gas and at that amperage the tungsten will grenade with no shielding. Sounds like it could be a grounding problem or a cable connection problem or even a machine problem. Try it on DCEN to see if you get can melt the aluminum. Sometime just switching the polarity switch around a few times can straighten things out if if it's the switch causing the problem.
John

[Bill Beauregard]

People will tell you that only a given tungsten will work. I have a lot of varieties which I use interchangeably on aluminum. Buying new, I try to get lanthanated. I've bought a bunch of old stock thoriated which I use as well. Zapster from the other network uses nothing else. His work shows it works very well. I'd guess you have a gas issue. Something is leaking, or sucking air.

[jonesk0668]

Thanks for all of your thoughts and advise! I am picking up a new bottle of gas this afternoon and gonna give it a try! I'll keep you posted!

Thanks,
KJ

[Fatjackdurham]

When I took my welding course, we did something with the tungsten to make a sort of round blob on the tip to weld aluminum, but I don't remember exactly what. Can someone remind me what that is? It was like we just ran an arc over the work or some steel and the tungsten melted into a sort of sphere.

Is your tungsten set up that way?

[hey_allen]

That sounds like transformer machine practices for pure tungsten.

I'm not an expert on this, but I've seen numerous people here saying that you don't need to do so on an inverter based machine, nor really want to run pure tungsten for aluminum, on an inverter machine.

[WTFH]

Well the old dog learned a new trick today. When jones said he could not form a puddle I immediately thought it was a machine problem and gas never entered my mind. In all my days of tig welding I have never seen what he said happened to him, until today. But then again I have never run a cylinder down to nothing or had an extremely low flow rate. I was just running a torch over aluminum forming a puddle and moving around and told a student to slowly turn the gas down and sure enough it happened. The arc went crazy jumping all over the place, very interesting! I was still able to form a puddle but it was all crapped up and at the same time my tungsten was going to heck too and I was never really able to reproduce the crazy arc without the tungsten going bad but I'm sure it could happen under the right conditions. I'm not sure at what flow rate this happened I just know it was below 10 cfh. I was using a standard gas lens and a #7 cup.

John

[LtBadd]

When I took my welding course, we did something with the tungsten to make a sort of round blob on the tip to weld aluminum, but I don't remember exactly what. Can someone remind me what that is? It was like we just ran an arc over the work or some steel and the tungsten melted into a sort of sphere.

Is your tungsten set up that way?

With the transformer machines it was common to "ball" the end of the tungsten by switching to reverse polarity, and at low amps initiate an arc on a clean piece of copper. The current flowing from the work piece would quickly ball the tungsten, thus using only minimal amps determined by the diameter of the tungsten

[jonesk0668]

Ok guys, not much change since last night...
I decided to give you all a look at my machine settings and the results. Don't really know where to go from here?

[Poland308]

Was the regulator reading 15 cfh during a purg cycle or is that all the time?

[jonesk0668]

During the purge.

[Poland308]

image.jpeg (36.96 KiB) Viewed 1143 times

[Poland308]

The gauge you have is a Borden tube style. The scale on it may read 15 cfh but ti can only sense pressure. That is why most people switch over to a floating ball gauge it shows flow.

[Poland308]

Your gauge may indicate 15 cfh but you might not be getting 15 cfh at you rig.

[Poland308]

You may have a restricted solenoid or gas passage. Your photos indicate a gas issue no question about that.

[jonesk0668]

I can hear gas coming from the nozzle...
Maybe like you said, not getting the 15 at the rig.

[Poland308]

Switch to or add a floating ball and you will see actually what is flowing. You can also find a floating ball gauge that you just hold over the end of your gas cup to read flow that might be a cheap option.

[jonesk0668]

I found the problem! My hose has cracked and it's leaking gas at connection.
Now just have to buy a new hose...

[Poland308]

It's always a relief when you can pin point a problem. At least hose is cheap.

[jonesk0668]

It's always a relief when you can pin point a problem. At least hose is cheap.

Thanks Josh for keeping me on the right track with the gas flow! I knew something was wrong when I changed the gauge and the problem didn't change. I then went to the solenoid and made sure it was working.
While I was down there, I could hear gas escaping from the connection. Upon further inspection, well, you see what I found.
A new cable/hose is $90 from Lincoln. Not bad.

I'll be sure to post an update when I get the new hose.

Thanks again!
KJ

[Bill Beauregard]

I believe it was Shovelon who explained it. A transformer based machine producing sine wave will struggle to initiate the EP half of the cycle. The ionization of gas making it electrically conductive is weak. The electrons leaving the workpiece are hampered by less conductive oxides, and contamination. It is late in the beginning of the half cycle that voltage builds to overcome resistance, and begin the arc. This renders the work negative portion of the cycle weaker. For reasons I don't understand pure tungsten was once used for aluminum. Despite the weak nature of return arc, it melted away the point. Might as well make a ball on the end to reduce the erosion. Inverters switch to the other polarity so quickly ionization isn't lost. The work negative half cycle is instant. It moves with the electrons, and corruption, heat. Pure tungsten is not an option with these machines. I would estimate 50/50balance in a transformer machine as similar in cleaning action to an inverter at 80%.

If you have an inverter, give away any pure tungsten. I believe the differences in other varieties are smaller than advertising would suggest. Thoriated has a minute level of radio activity. 2% lanthanated is versatile. others work OK.

[soutthpaw]

A flow gauge for checking the actual gas flow at the end of your torch would have found that problem much quicker. There are about 10 to 30 bucks

[jonesk0668]

UPDATE!
I got my new hose, hooked it up, flipped the switch and struck an arc. All is good in TIG land again!
Thanks for all of the comments and advise!

KJ