Can't weld aluminum with DC TIG but can with DC MIG?

[undercut]

Why is it that I see people who can weld aluminum with DC MIG but DC TIG, you can't?

 

[Shield Arc]

Who told you that? Here is a aluminum Tig weld done on DC.

 

[undercut]

Who told you that? Here is a aluminum Tig weld done on DC.

I see so many DC inverter TIG products that specifically state they will not weld aluminum (well).

 

[Shield Arc]

When Linde now ESAB invented Tig welding it was all DC, with helium gas.

 

[undercut]

When Linde now ESAB invented Tig welding it was all DC, with helium gas.

I actually wanted to know why someone can MIG aluminum with argon but can't TIG aluminum with argon.

 

[dstig1]

I actually wanted to know why someone can MIG aluminum with argon but can't TIG aluminum with argon.

Well allow me to talk out of my behind for a moment...:laughing:

For TIG, as I understand it, Ar does does support as high of a ionization potential as He does, so you don't get as much heat into the weld quickly enough. Since Al is such a good conductor, you need to supply a lot of heat fast to weld without just melting the whole thing into a blob. Using AC cleans off the oxide also, making the weld better as it removes the oxide that can contaminate the weld. There is some relation to the oxide cleaning in why DC TIG on AL is so much harder, I think.

Here's an explanation:
Why can't you TIG weld Aluminium with DC current?

MIG is a different animal as the electrode is also the filler. I assume that makes the difference, though I won't even try to guess why....I've already made up enough stuff for one post.:laughing:

 

[Shield Arc]

One nice benefit to Tig welding aluminum on DC with helium, is you can do the same thing as with AC but it only takes about half the amps.

Down side is, you don't get as much cleaning action out of the arc, and there is a very small window where the arc will start.

 

[Jorville]

When Linde now ESAB invented Tig welding it was all DC, with helium gas.

Here is a good read that might interest you. I did not know the history of Tig until googled it. I often wondered who invented it, when it was invented. The first I heard about it was aboard ship in 1965. No offence intended

History of TIG Welding

This information came off another site.

Development

After the discovery of the electric arc in 1800 by Humphry Davy, arc welding developed slowly. C. L. Coffin had the idea of welding in an inert gas atmosphere in 1890, but even in the early 20th century, welding non-ferrous materials like aluminum and magnesium remained difficult, because these metals reacted rapidly with the air, resulting in porous and dross-filled welds.[2] Processes using flux-covered electrodes did not satisfactorily protect the weld area from contamination. To solve the problem, bottled inert gases were used in the beginning of the 1930s. A few years later, a direct current, gas-shielded welding process emerged in the aircraft industry for welding magnesium.[3]
This process was perfected in 1941, and became known as heliarc or tungsten inert gas welding, because it utilized a tungsten electrode and helium as a shielding gas. Initially, the electrode overheated quickly, and in spite of tungsten's high melting temperature, particles of tungsten were transferred to the weld.[3] To address this problem, the polarity of the electrode was changed from positive to negative, but this made it unsuitable for welding many non-ferrous materials. Finally, the development of alternating current units made it possible to stabilize the arc and produce high quality aluminum and magnesium welds.[3]
Developments continued during the following decades. Linde Air Products developed water-cooled torches that helped to prevent overheating when welding with high currents.[4] Additionally, during the 1950s, as the process continued to gain popularity, some users turned to carbon dioxide as an alternative to the more expensive welding atmospheres consisting of argon and helium. However, this proved unacceptable for welding aluminum and magnesium because it reduced weld quality, and as a result, it is rarely used with GTAW today.[5]
In 1953, a new process based on GTAW was developed, called plasma arc welding. It affords greater control and improves weld quality by using a nozzle to focus the electric arc, but is largely limited to automated systems, whereas GTAW remains primarily a manual, hand-held method.[5] Development within the GTAW process has continued as well, and today a number of variations exist. Among the most popular are the pulsed-current, manual programmed, hot-wire, dabber, and increased penetration GTAW methods.[6]

 

[Shield Arc]

That is very interesting! So Linde bought the patent:laughing:. Can't tell you how many times over the years I've read where Linde invented the process. I'm sure I've even read it in welding books. Goes to show you, don't always believe what you read, wait a minute! Am I believing what was printed in your link? :laughing:

 

[Jorville]

That is very interesting! So Linde bought the patent:laughing:. Can't tell you how many times over the years I've read where Linde invented the process. I'm sure I've even read it in welding books. Goes to show you, don't always believe what you read, wait a minute! Am I believing what was printed in your link? :laughing:[/QUOTE
]
Shield arc I am not trying to pick a fight with you in any way, I am just sharing information that I have found. I would like to give credit where credit is due.

What I posted was not to offend you in any way. Here is another comical link that they claim was researched. You should get a few laughs out of this also.

Who invented tig welding? | Answerbag

I found another link, It's 125 years of Linde http://www.the-linde-group.com/en/images/chronicle_e[1]14-9855.pdf

On page 46 I found the only reference to electric welding

During the war, Ellira (Elektro-Linde-Rapidschweiﾟung), the
electric welding systems department established in H?lriegelskreuth in 1937, worked almost exclusively on supplying welding
equipment for the arms industry.

On page 86 and 87 they have milestones of Linde From 1879 to 2004, they never mentioned their invention of the Tig welding process. They either forgot to put it on the list or it was such an insignificant invention it was not worth mentioning.

I will look some more and see if I can find somewhere where Linde claims they invented the process.

Can anybody else on here help me out?

 

[Shield Arc]

Oh I wasn't offended, no way, no how! I'm always amazed at what I don't know about welding. I'm just one step above your average hack.

 

[Jorville]

shield arc I have only once saw someone show you disrespect. You can see that on site comments where you go by Puddles. You have done an excellent job helping Lanse with his projects. And all the knowledge you have shared over the internet. You have shown total professionalism on both sites I see your posts on. I would never call you a hack or anything disrespectful. Keep up the good work and have a great day.

 

[Shield Arc]

shield arc I have only once saw someone show you disrespect.

I don't remember that at all! Everyone is entitled to their opinion, majority of the time, mine differs from everyone else's.:laughing:

Honestly, I'm not much of a weldor! I worked way more years as a rigger than a weldor.

 

[Jorville]

I actually wanted to know why someone can MIG aluminum with argon but can't TIG aluminum with argon.

It looks like no one ever answered your question. I thought it was the industry standard to Tig with argon, Aluminum included. You can't Tig with 75/25, doesn't work for beans. I have found a gas lens helpful in Tig welding welding aluminum. Using argon I have Tig welded brass,aluminum ,steel and stainless steel.

Helium was the first cover gas for Tig, (that is where Heliarc came from) Helium makes a poor cover gas because it is lighter than air. It was never used for a cover gas on a Tig machine where I worked.

 

[Mark @ Everlast]

DC TIG is a matter of polarity...while it is TECHNICALLY possible to TIG Aluminum with DC, it isn't at all practical.

If you weld in DCEN, you will have nothing but an oxide layer laying on top, even with the cleanest metal. At the very least it will be sooty and dirty.
If you weld with DCEP it will provide the cleaning you need, BUT it will be very hot, and you'll need a huge tungsten and a large torch for low amp welds...and your cleaning area will be huge.

Argon still is the standard for DC TIG and AC TIG. Helium CAN be added to improve the penetration and cleaning if needed.

Anyone trying to sell you a DC tig to do Aluminum is a moron. In a pinch you can make it work, but it is not with the ease or quality of AC.

Watch this...and you'll see exactly what I mean:
http://www.youtube.com/watch?v=RG4ZOwSw9CQ&feature=plcp