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Up Topic Welding Industry / General Welding Discussion / Questioning Thermal Arc's Reputation
- - By welder_guy2001 (***) Date 02-29-2004 21:43
Has anybody here had any trouble welding aluminum w/ a Thermal Arc 185?

I've been trying to find the ideal settings for welding 3/16" and 1/4" aluminum. My problem starts w/ the 1/8" pure tungsten melting into a big nasty ball at only 170 amps. Yes, I am using AC current and I've tried adjusting the wave balance from 10% to 65% negative charge. I've tried adgusting the AC frequency from 10 Hz to 150 Hz. I've tried a 5/32" pure tungsten thinking maybe that would carry the amps w/o melting into an ugly ball...wrong. How is it possible for a 5/32" pure tungsten to meltdown at only 170 amps? I've also adjusted the pure argon gas flow from 20 cfh to 30 cfh. I've also tried the pulser.

As if the melting tungsten isn't enough, the arc dances around wherever it wants to go. And in the rare occassion that I did get both sides of the joint melted, as soon as I got the filler rod close to the puddle the arc went wild.

I'm a pretty good TIG welder when it comes to aluminum, but this welder has me baffled! I've welded 3/8" aluminum w/ a 1/8" tungsten on a different welder and never had the problems this welder is giving me.

I'm really hoping it's just a glich w/ my welder's circuitry and not the particular design of the welder itself. Anybody have a clue?
Parent - - By Lawrence (*****) Date 02-29-2004 23:59

Go between 65 and 85% negative on your AC Balence control. If your really running 10% negative that means of course your running 90% positive which puts most of the heat on the electrode rather than the work. You need to balence the other direction :)

Loose the Pure tungsten, it has poor arc transfer and the lowest melting point of all TIG electrode choices. The newer power sources will do just fine with a sharpened (and blunted) Zirconium, Cerium or Thorium, tungsten.

Make sure your water cooled torch is getting good flow and use a full length tungsten for best heat sinking.
Parent - - By welder_guy2001 (***) Date 03-01-2004 03:58
I've tried getting zirconiated tungsten at the welding supply stores here in town (Anchorage, Alaska) and niether of them have ANY. Interesting huh? Also, the Thermal Arc 185 comes w/ a gas cooled torch...I wish it was water cooled though.

Possibly it's just the tungsten that's giving me problems.
Parent - By awill4wd (**) Date 03-01-2004 10:14
I agree with Lawrance here, I think the pure tungsten is your problem, it simply can't carry the current the others can. Personally I prefer Ceriated for high currents, I find it outperforms Zirconated particularly when ground to a point. I've never really liked Thoriated for welding aluminium as it doesn't seem as stable as the Ceriated but that is my own preference and I know that others swear by them.
That being said I do prefer Thoriated for DC welding.
Regards Andrew.
Parent - - By welder_guy2001 (***) Date 03-02-2004 03:22
I tried 2% 3/32" thoriated today and it seemed to be better than using pure tungsten. Then, in search of something better, I broke down and got some 1.5% 1/8" lanthanated tungsten to see how that works. That's better than thoriated, and much better than pure, but still not the best. I suppose I'm gonna have to order some zirconiated and ceriated over the internet.

Another strange thing somebody told me at AirGas...they didn't have any zirconiated or ceriated...and they said that ceriated is very rarely used. I think the people up here are really in the dark when it comes to new products. I mean, they're selling the newest welding machines, but they don't sell the consumables you REALLY need to make the machines work!
Parent - - By ssbn727 (*****) Date 03-02-2004 05:48
Hi Welder_guy2001!
Maybe they want you to go through more tungstens so you could buy more???
Check out any of the internet sites that you can order from yet?

Respectfully,
SSBN727 Run Silent... Run Deep!!!
Parent - - By welder_guy2001 (***) Date 03-02-2004 06:28
HA HA! I'm sure...Alaska is turning out to be one of the strangest places to live because we're the last state to get any kind of technology!

I've been doing some research on the Miller website and found out some things that are totally different from the way I used to TIG weld. I always thought that you could still run pure tungsten on inverters even if they put out square waves. I never understood the physics of why you balled a pure tungsten vs. sharpening a thoriated tungsten for work on stainless or mild steel.

I also found out that you can use 2% thoriated tungsten for welding aluminum, although, it's not the best you can get. I have seen the light! (no pun intended)
Parent - - By LarryL (**) Date 03-02-2004 14:52
"HA HA! I'm sure...Alaska is turning out to be one of the strangest places to live because we're the last state to get any kind of technology!"
----------

Our area may be a welding backwater also. Although Fresno, Calif., has close to a half million residents, the largest welding supplier here still recommends pure tungsten electrodes for GTAW welding of aluminum. If one wants to buy any kinds of tungsten electrodes besides pure and thoriated ones, they have to be special ordered.

Continuing with my own trial-and-error search for the best type of electrodes I can use for aluminum, I've found that my zirconiated ones have the most directional stability with my Thermal Arc inverter. That is, the arc consistently comes straight off the tip and I can point it at the root of a fillet. I've been trying thoriated and ceriated ones but, after a few minutes of welding, these produce arcs that come off the side at an angle. My zirconiated electrodes, however, do not withstand the amperage as well as thoriated and ceriated ones. Yesterday, for example, I was welding 1/8" stock at 125 to 150 amps AC (80% EN, 150 cycles/sec.). My 3/32" zirconiated electrode's tip gradually rounded up until it became a ball. A previous trial with a 3/32" thoriated one resulted in an angulated arc from the side, even though the tip remained quite sharp. I'm waiting for an order of 3/32", 1.5% lanthanated electrodes to arrive so that I can experiment with that type. As Lawrence mentioned in a previous message, some manufacturers produce better electrodes than others. He's found that some brands are superior to others. Buying all these electrodes to determine which is best for aluminum, however, can result in quite an expense!


Parent - - By welder_guy2001 (***) Date 03-03-2004 03:18
I've been welding w/ 1/8" 1.5% lanthanated at 130-185 amps, 80% EN, 130-150 Hz on 1/4" and 3/16" aluminum today. I must say, after getting the right set-up, this is the most remarkable AC arc I've ever seen! But it seems that the lanthanated tungstens do tend to wear out after a while. I've been sharpening it and blunting the tip so there is a .010" wide land on the end. Sometimes I've noticed the tungsten kinda spits, but it doesn't spit into the weld...more like a tiny explosion happens because I can see a tiny spark fly off to the side. Over time the tip erodes and needs to be re-ground.

I tried my 3/32" thoriated tungsten too, but that didn't seem to be putting out the heat I needed for the 1/4" aluminum.

I guess all of this is a huge revelation to me because the guy I worked for a while ago had a Thermal Arc 300 or something like that and only used pure tungsten on it. He had an older Miller machine that also used pure tungsten, and looking back on things, the Miller didn't burn up tungsten nearly as fast as the Thermal Arc. I don't believe he knows what his inverter is capable of doing, and he is passing on that incorrect knowledge to any employees he has. That's why I found it so frustrating when I couldn't do the same thing w/ my machine. Nothing against old guys, but some of them are just too set in their ways...and when they try to jump into some new technology they try to mix the new w/ the old to come up w/ something better, which actually hurts them economically.
Parent - By Lawrence (*****) Date 03-03-2004 12:51

Here you go friend. the first link is to a PDF file from Miller electric. I have printed and laminated the thing and posted it right next to my new power sources. Sometimes the Old Dogs just won't go by word of mouth. So print up this article by Mike Sammons of Miller electric and hand it to your friend. Even tho the article is from Miller the technology is the same as with your powersource.

http://www.millerwelds.com/pdf/Aluminations_Ad_Package.pdf


http://www.millerwelds.com/education/tech_articles/articles30.php

Up Topic Welding Industry / General Welding Discussion / Questioning Thermal Arc's Reputation

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