TIG Welding Problems

[cobrawanabe1699]

Hey everyone, I have a question for you...

First, here's the background....
-The welder in question is a brand-spankin' new Miller Syncrowave 200
-I know (as I have checked the entire gas delivery system) that the argon is making it to the gun
-I am attempting to weld 6061-T6 aluminum in DCEN (direct current electrode negative)
-I am using 7" long, pure tungsten electrodes (green band) in 3/32 dia.
-The gun (electrode holder and gas/electical line) is a Weldcraft (can't remember the model)
-I have the ground clamp postioned as close as possible to my workpiece, which is on a steel bench.
-I have tried to clean the elecrode in AC, but the problem persists...

Here's the problem...

In order to get a puddle, I have to strike an arc on the metal. But with this machine (I have used the same model before), that should not be necessary. As soon as the electrode gets within 1/4 to 1/8 of an inch of the metal, the arc should show up, no matter how much I'm on the pedal. By striking the arc, I am in turn contaminating the elctrode, and ruining the weld before I have even formed a puddle. The puddle does not appear shiny, and the electrode ends up black, without a properly balled tip. I have checked my settings time and time again, and have practically memorized all the literature that was shipped with the machine. I have also read the welding process books at my school almost religiously for the last three years, and am a pretty experienced TIG welder for my short 17 years, especially with 6061 aluminum.

Is it me or the machine? What in the world am I doing wrong? I think it may possibly be a current problem with the machine, as a group of my colleagues set up the machine without my supervision.

Thank you so much for your help!

[DonRotolo]

Originally Posted by cobrawanabe1699

I think it may possibly be a current problem with the machine, as a group of my colleagues set up the machine without my supervision.

It cannot hurt to perform the setp again as per the book, as a double-check.

Remember, an arc needs voltage to form (as in "jump across the gap"), not current. Current only comes into play once the plasma arc is formed.

Having no experience with TIG I really can't answer the question directly, but I hope what I wrote helps.

Don

[Greg Needel]

sounds to me like you are not getting gas flow. Are you sure you have your regulator set high enough and that you have the correct flow nozzle on your gun for the size of the material. Also check to see if your gas ports on your gun are clogged.

Also how fine of a point do you have ground on your tungsten?

[cobrawanabe1699]

Originally Posted by Don Rotolo

It cannot hurt to perform the setp again as per the book, as a double-check.

Remember, an arc needs voltage to form (as in "jump across the gap"), not current. Current only comes into play once the plasma arc is formed.

Having no experience with TIG I really can't answer the question directly, but I hope what I wrote helps.

Don

It does help, as you brought up a good point. Thanks!

Originally Posted by Greg Needel

sounds to me like you are not getting gas flow. Are you sure you have your regulator set high enough and that you have the correct flow nozzle on your gun for the size of the material. Also check to see if your gas ports on your gun are clogged.

Also how fine of a point do you have ground on your tungsten?

I had originally suspected such a problem, and was told over and over by peers that the gun was getting gas. I'm not so sure if they know what they are talking about, since I can't hear the afterflow. I thought it may have just been a quiet gun Stupid me...

I had ground the tungsten to a sharp point, but isn't the tip supposed to ball up while welding aluminum?

[Greg Needel]

Originally Posted by cobrawanabe1699

I had ground the tungsten to a sharp point, but isn't the tip supposed to ball up while welding aluminum?

it should be a fat sharp point, something like the geometry of a golf pencil (but smaller obviously)

[Dick Linn]

I'm Dick's son. I think your main problem is that you need to be using AC high frequency continuous. Gas flow should be about 10-15 CFH, mainly depending on your cup size. I don't think that particular machine has a preflow so you need to hold the torch in the air, depress the pedal so it goes into postflow mode and before it turns off go to where you want to strike up. With the gas flowing press the pedal about a quarter of the way down and wait for the high frequency to start the arc (it ionizes the argon and then goes to welding amps). The electrode should be tapered and will ball up on its own when you weld. You should not have to scratch start hold the electrode about 1/8" away from your work. With aluminum clean the work with a STAINLESS brush for aluminum only, and clean your filler with a scotch brite for aluminum only. Keep your filler very low (about 10-15 degrees off work). Try connecting the ground clamp to the workpiece at least once or make sure the table actually makes good contact with the aluminum. Also, before I forget make sure it is in TIG mode! Use the tig weld calculator on the miller website to adjust your max amps and pay attention to the duty cycle!

Once again make sure it is clean. When you are done cleaning it, clean it some more. Aluminum tends to get "sucked" onto the tungsten so if that happens just break it off with pliers carefully and either point it or let it ball if its a clean break.

I've welded aluminum up to 260 amps (not fun) and spent the summer welding Inconel turbine blade tips (also not fun).
Wordy I know but these are the basics.

[cobrawanabe1699]

Originally Posted by Dick Linn

I'm Dick's son. I think your main problem is that you need to be using AC high frequency continuous. Gas flow should be about 10-15 CFH, mainly depending on your cup size. I don't think that particular machine has a preflow so you need to hold the torch in the air, depress the pedal so it goes into postflow mode and before it turns off go to where you want to strike up. With the gas flowing press the pedal about a quarter of the way down and wait for the high frequency to start the arc (it ionizes the argon and then goes to welding amps). The electrode should be tapered and will ball up on its own when you weld. You should not have to scratch start hold the electrode about 1/8" away from your work. With aluminum clean the work with a STAINLESS brush for aluminum only, and clean your filler with a scotch brite for aluminum only. Keep your filler very low (about 10-15 degrees off work). Try connecting the ground clamp to the workpiece at least once or make sure the table actually makes good contact with the aluminum. Also, before I forget make sure it is in TIG mode! Use the tig weld calculator on the miller website to adjust your max amps and pay attention to the duty cycle!

Once again make sure it is clean. When you are done cleaning it, clean it some more. Aluminum tends to get "sucked" onto the tungsten so if that happens just break it off with pliers carefully and either point it or let it ball if its a clean break.

I've welded aluminum up to 260 amps (not fun) and spent the summer welding Inconel turbine blade tips (also not fun).
Wordy I know but these are the basics.

Whoah Thanks!

One question...
I was taught how to TIG with this same machine (at LOLHS), and IIRC, we were welding in DCEN... Am I just mistaken? (I haven't TIGed since the 2008 build season )

[spazdemon548]

Steel is welded in DCEN, but when welding aluminum, use AC. Also, to prep your tungsten tip, put the unit on DCEP and strike a short arc on your work piece. This will melt the tip to a nice ball w/ a dia. of about 1 1/2 the thickness of the tungsten. Don't forget to put it back on AC though when your done, or you'll melt the torch.

Originally Posted by cobrawanabe1699

Whoah Thanks!

One question...
I was taught how to TIG with this same machine (at LOLHS), and IIRC, we were welding in DCEN... Am I just mistaken? (I haven't TIGed since the 2008 build season )

[Dick Linn]

If you were TIG welding aluminum it couldn't have been DCEN or DCEP. TIG welding aluminum is only possible with AC high frequency with that machine because DCEP pulls oxides from the aluminum surface but will melt the tungsten with 2/3 heat on it. DCEN provides 2/3 heat to the work without melting the tungsten. AC changes between the two 60 times a second but the HF is required to maintain the arc between cycles.

DCEN welding aluminum is only for stick welding which is recommended for 1/4" and thicker.

Hope this helps. Sounds like someone set the machine up and didn't really explain everything. If all else fails there's the machinist's response, "the answer is in a book somewhere". I would recommend finding a copy Welding Principles and Applications by Larry Jeffus.

Edit: I've tried Spazdemon's suggestion many times for balling the tungsten but really only to save time or guarantee a good tip.

-Tan Linn

[Alan Ing]

There is a wealth of knowledge on the Miller site (www.millerwelds.com) that gives you basic settings for all welding processes including TIG as well as technique suggestions. There is even a TIG calculator which helps you set up your machine for different materials and thicknesses. Check out

http://www.millerwelds.com/resources...ur-skills/tig/

It tells you that you need to use AC High Frequency for Aluminum as well as the initial settings to use for the thickness and type of weld you want to make.

Welding is Fun!

[AJ R]

Sounds like you got it fixed. One thing that happened to me was the petal was too close to the welding table and was getting caught, so I couldn't push it down all the way.

[Dick Linn]

DCEN is sometimes used for TIG welding of thick aluminum, with lab-grade helium used as a shielding gas. Here's a forum thread about it:

http://hobartwelders.com/weldtalk/sh...ad.php?t=25034

[DarkFlame145]

Originally Posted by cobrawanabe1699

Hey everyone, I have a question for you...

First, here's the background....
-The welder in question is a brand-spankin' new Miller Syncrowave 200
-I know (as I have checked the entire gas delivery system) that the argon is making it to the gun
-I am attempting to weld 6061-T6 aluminum in DCEN (direct current electrode negative)
-I am using 7" long, pure tungsten electrodes (green band) in 3/32 dia.
-The gun (electrode holder and gas/electical line) is a Weldcraft (can't remember the model)
-I have the ground clamp postioned as close as possible to my workpiece, which is on a steel bench.
-I have tried to clean the elecrode in AC, but the problem persists...

Here's the problem...

In order to get a puddle, I have to strike an arc on the metal. But with this machine (I have used the same model before), that should not be necessary. As soon as the electrode gets within 1/4 to 1/8 of an inch of the metal, the arc should show up, no matter how much I'm on the pedal. By striking the arc, I am in turn contaminating the elctrode, and ruining the weld before I have even formed a puddle. The puddle does not appear shiny, and the electrode ends up black, without a properly balled tip. I have checked my settings time and time again, and have practically memorized all the literature that was shipped with the machine. I have also read the welding process books at my school almost religiously for the last three years, and am a pretty experienced TIG welder for my short 17 years, especially with 6061 aluminum.

Is it me or the machine? What in the world am I doing wrong? I think it may possibly be a current problem with the machine, as a group of my colleagues set up the machine without my supervision.

Thank you so much for your help!

Is your high frequency on continuous, or is it just on start? Start is only for steel and stainless, you need Continuous to help break the oxide layer along with the DCNeg current flow.

[cobrawanabe1699]

Thank you for all of your advice, everyone. I do appreciate it. But I have come to the conclusion that the machine is not getting gas to the gun. Is there any way to clear the lines? They are brand new, so I wasn't expecting this problem. I have already made sure that the gas is atleast getting to the back of the machine, since when the tank is opened slightly, gas comes out of the end of the tank line.

[DarkFlame145]

Replace the lines and or gun/line