It is currently Fri Apr 28, 2017 12:12 am Advanced search

Aluminum on DC

Tig welding tips, questions, equipment, applications, instructions, techniques, tig welding machines, troubleshooting tig welding process

Aluminum on DC

Postby Farmwelding » Mon Mar 13, 2017 9:33 pm

So fi tried running some aluminum in DCEN today on some 1/8" at like 120-130 amps with 100% argon. When I did it the aluminum just deflated and sunk in. I know in all the videos, they use helium, but why won't it work with just argon-to much heat directly from DCEN? I don't know maybe one of you does.
A student now but really want to weld everyday. Want to learn everything about everything.
warning!! Bad English may be in post. It's off a phone/autocorrect. I've had teachers with worse spelling!
Instagram: @farmwelding
Nick
Farmwelding
Weldmonger
 
Posts: 909
Joined: Thu Mar 10, 2016 11:37 pm
Location: Wisconsin

Re: Aluminum on DC

Postby Coldman » Mon Mar 13, 2017 9:50 pm

What are they teaching you in school?
Gas shield has nothing to do with it.
Aluminium melts at a lot lower temperature than does its oxide layer. You have to remove the oxide layer to weld the virgin aluminium beneath. the EP part of AC GTAW does this. If you use DCEN only, before you melt the oxide layer the virgin aluminium beneath melts and collapses away as you have found. That's why aluminium is tigged AC. You can use DCEP to remove the oxide layer and weld, but your gonna need a 1/4" or bigger electrode to handle the heat.
Flat out like a lizard drinkin'
Coldman
Weldmonger
 
Posts: 949
Joined: Mon Dec 15, 2014 2:16 am
Location: Oz

Re: Aluminum on DC

Postby Otto Nobedder » Mon Mar 13, 2017 10:26 pm

Coldman wrote:What are they teaching you in school?
Gas shield has nothing to do with it.
Aluminium melts at a lot lower temperature than does its oxide layer. You have to remove the oxide layer to weld the virgin aluminium beneath. the EP part of AC GTAW does this. If you use DCEN only, before you melt the oxide layer the virgin aluminium beneath melts and collapses away as you have found. That's why aluminium is tigged AC. You can use DCEP to remove the oxide layer and weld, but your gonna need a 1/4" or bigger electrode to handle the heat.


Aluminum can, and in certain circumstances is required to be, welded DCEN.

Pure helium is one requirement, for the heat transfer it allows. Surgical cleanliness is the other.

Roy Crumrine (@crummywelding on Instagram and one of the hosts of the WT&T podcast) has experience with it. He has posts here on the subject, under an old username, rediron881.

Here's the topic:
viewtopic.php?t=2002

Steve S
User avatar
Otto Nobedder
Weldmonger
 
Posts: 8044
Joined: Thu Jan 06, 2011 11:40 pm
Location: Near New Orleans

Re: Aluminum on DC

Postby Coldman » Tue Mar 14, 2017 12:07 am

I am aware that with special setup and technique it can be welded DCEN with helium. Highly specialised and kinda rubs the grain up the wrong way a little after all we've been taught. I don't do enough ally and don't keep helium so never gonna experiment. I'll stick with good ole tried and proven square ac with argon.
Flat out like a lizard drinkin'
Coldman
Weldmonger
 
Posts: 949
Joined: Mon Dec 15, 2014 2:16 am
Location: Oz

Re: Aluminum on DC

Postby cj737 » Tue Mar 14, 2017 7:47 am

Coldman wrote:I am aware that with special setup and technique it can be welded DCEN with helium. Highly specialised and kinda rubs the grain up the wrong way a little after all we've been taught. I don't do enough ally and don't keep helium so never gonna experiment. I'll stick with good ole tried and proven square ac with argon.


This brings to mind a maxim about a lifetime of learning possibilities-
"The moment you believe you have all the answers, is the moment you have begun asking all the wrong questions."

And there's one thing I learned early about welding, and that's no one knows everything about welding. It appears to me to be much like the game of chess; easy to learn to play, a lifetime to master.
cj737
Ace
 
Posts: 281
Joined: Thu Sep 29, 2016 8:59 am

Re: Aluminum on DC

Postby exnailpounder » Tue Mar 14, 2017 7:53 am

cj737 wrote:
Coldman wrote:I am aware that with special setup and technique it can be welded DCEN with helium. Highly specialised and kinda rubs the grain up the wrong way a little after all we've been taught. I don't do enough ally and don't keep helium so never gonna experiment. I'll stick with good ole tried and proven square ac with argon.


This brings to mind a maxim about a lifetime of learning possibilities-
"The moment you believe you have all the answers, is the moment you have begun asking all the wrong questions."

And there's one thing I learned early about welding, and that's no one knows everything about welding. It appears to me to be much like the game of chess; easy to learn to play, a lifetime to master.

Amen! I thought I was a great chess player til I played an old-timer down at the VFW...he kicked my ass so bad, every game..and he told me how he did it. He had me beat after my second move :(
Ifyoucantellmewhatthissaysiwillbuyyouabeer.
exnailpounder
Weldmonger
 
Posts: 2246
Joined: Thu Dec 25, 2014 9:25 am
Location: near Chicago

Re: Aluminum on DC

Postby Olivero » Tue Mar 14, 2017 10:09 am

The alternating current is half clean half heat, that's the simple version,

So it removes or more like bombards the surface of the aluminum in order to wreck that oxide layer and expose the jewel within that you are trying to melt, without removing the oxide layer you can pump as much darn heat on it as you want and the moment enough of it is hot enough, it sinks due to gravity, it sucks really......

So anyways, I have heard it can be done but I never did it and never had a need for it but that's probably why it didn't work.
if there's a welder, there's a way
User avatar
Olivero
Ace
 
Posts: 290
Joined: Tue Dec 13, 2016 9:24 pm
Location: Clearwater Florida

Re: Aluminum on DC

Postby pgk » Tue Mar 14, 2017 11:21 am

Farmwelding wrote:So fi tried running some aluminum in DCEN today on some 1/8" at like 120-130 amps with 100% argon. When I did it the aluminum just deflated and sunk in. I know in all the videos, they use helium, but why won't it work with just argon-to much heat directly from DCEN? I don't know maybe one of you does.


Pickup a small tank of Helium and maybe try using some thicker aluminum to practise on, dc on aluminum doesn't need much amperage compared to ac. Like the posts above make sure the aluminum is clean, clean clean. :) I haven't done much aluminum using dc but I did notice that it didn't get that shiny look to it when it was ready to add filler. Good luck ;)
Esab SVI 300, 150 wire feeder, 30A spool gun, Miller Passport, Dynasty 300 DX, Coolmate 4, Spectrum 2050, C&K Cold Wire feeder WF-5
User avatar
pgk
Workhorse
 
Posts: 63
Joined: Mon Feb 09, 2015 4:48 pm
Location: Michigan

Re: Aluminum on DC

Postby cj737 » Tue Mar 14, 2017 11:26 am

Not to belabor a point, but, I can think of heaps of folks who should learn this technique; all who have a DC TIG only. It provides a much wider reach of welding when you can TIG aluminum. A bottle of Helium is far less expensive than a new AC/DC Inverter. Perhaps those who haven't tried it don't weld aluminum, or have AC in their shop. But lots of folks don't.

As for the OP, who's in school experimenting, this a great place to learn, try and discover. Just gotta follow the rules of 100% Helium with aluminum on DC is all.

I use 50%/50% frequently with my AC box on thick aluminum because I'm amp-limited (200). Cheaper to add He than to buy a new $4k TIG box.
cj737
Ace
 
Posts: 281
Joined: Thu Sep 29, 2016 8:59 am

Re: Aluminum on DC

Postby cherwolf » Tue Mar 14, 2017 12:17 pm

Never welded AL.

But if I had to weld a cracked aluminum tipper`s body. (one of previous job boss wanted somebody to fix his trucks, was welding noob then). You have AC Tig machine.

How would you prepare and weld such task? (Let`s say crack is on the side and at angle 45 dgerees up, you can`t clean inside oxide layer)
cherwolf
Active Member
 
Posts: 39
Joined: Thu Oct 30, 2014 11:13 am
Location: Latvia

Next

Return to Tig Welding - Tig Welding Aluminum - Tig Welding Techniques - Aluminum Tig Welding