[av8r]

I have two small pieces of aluminum to join. I have been considering options like soldering (with Alumiweld), stick (with E4043) or TIG. I know that aluminum TIG is normally pulsed to allow for surface cleaning. My multi-process welder has TIG DC- without pulse. Do you think I could do this small aluminum job with DC+? I'm thinking DC+ to keep more heat on the tungsten.

[rake]

You won't be happy. DC+ is gonna burn back the tunsten. You said multi process?
Mig it. I have migged aluminum in a pinch without a spool gun. .030 wire, .035 tip,
blow out and clean your conduit and spray teflon dry lube in it. Set your wire tension
to not crush the wire and position your machine do the conduit is as straight as possible.
100% argon and push the puddle. Don't pull it! Preheat! Plenty of preheat! and a NEW SS
wire brush! NEW!

[ajlskater1]

DC positive can weld aluminum and actually does a very good job on really thin stuff like .030 and under. Iv you use it for stuff much thicker than that the tungsten is going to ball up extremely bad.

[ksmrf]

IF someone was going to try this??????
What tungston would a person us?

[Otto Nobedder]

I'd think pure would be the only choice, and at least one size larger than you'd use for a similar HFAC weld. Alloy Tungstens are more likely to splinter than pure. There was another discussion on this recently, and I'll see if I can dig up the topic.

Steve S

[weldin mike 27]

I saw a you tube clip of a Bulgarian dude using DC- inverter to weld Al using an Al stick rod as filler. The coating of the rod helped to break down the surface oxides. Wasnt perfect but worked.

[MinnesotaDave]

Sections must be thin because of the low current carrying ability of the tungsten on DC+

3/32" carries about 30 amps
1/8" about 40 amps.

I'm sure each would carry more for short bursts of welding.

I have done this and it works just fine.

[weldin mike 27]

On second inspection of the question , i know of an instance of this practice . Very thin Al used with a very thick elecrode, 3/16 ish. The heat is soaked up by the thick electrode and doesnt obliterate the thin al.

Mick

[ksmrf]

Im learning loads of neat tricks on these forums....

[Bill Beauregard]

I tried it as an experiment. Arc was very smooth, no evident cleaning action. It seemed to flatten the bead out with only a few cracks in the oxide layer allowing filler to flow beneath the oxide. I don't know that I would choose DC but it wasn't as bad as I expected.

[MinnesotaDave]

I tried it as an experiment. Arc was very smooth, no evident cleaning action. It seemed to flatten the bead out with only a few cracks in the oxide layer allowing filler to flow beneath the oxide. I don't know that I would choose DC but it wasn't as bad as I expected.

You should see a wide cleaning band as you are only using the cleaning side of the polarity, DCEP

That was my experience with it.

If on DCEN, like for welding steel, no cleaning action and you get the results you listed.

[Bill Beauregard]

I tried it as an experiment. Arc was very smooth, no evident cleaning action. It seemed to flatten the bead out with only a few cracks in the oxide layer allowing filler to flow beneath the oxide. I don't know that I would choose DC but it wasn't as bad as I expected.

You should see a wide cleaning band as you are only using the cleaning side of the polarity, DCEP

That was my experience with it.

If on DCEN, like for welding steel, no cleaning action and you get the results you listed.

I'm starting to question my memory, might I have been DCEN? I'll try again to see.

[AKweldshop]

how do you run a tig torch DCEP????
I had my leads swiched one day, and "boom", went off like a firecracker inside the tig cup.
how do you do it?

~John

[MinnesotaDave]

how do you run a tig torch DCEP????
I had my leads swiched one day, and "boom", went off like a firecracker inside the tig cup.
how do you do it?

~John

How much current did you try punch through it?

Consider these numbers from my earlier post:
3/32" carries about 30 amps DCEP
1/8" about 40 amps DCEP

Not much to play with, try hammer 200 amps and I bet it blows apart

We pushed the limits welding with DCEP and eventually ours started to quiver and BAM - it was gone

[AKweldshop]

OK my bad. I was using about 120 amps 3/32 tungsten.
Ok,
~John

[Bill Beauregard]

how do you run a tig torch DCEP????
I had my leads swiched one day, and "boom", went off like a firecracker inside the tig cup.
how do you do it?

~John

I tried it again reverse polarity with 1/8" thoriated on 1/4". It balled up the tungsten fast. I could weld, but not well. I got a lot of black, I think so much turbulence from the torch it was sucking in air.

Switching to straight polarity EN I don't see what the fuss is about. It is necessary to force the rod in, breaking under the slag that looks like the scummy layer that forms on liquid lead when making bullets for muzzle loader. After it cools it isn't quite as pretty as AC, but brush it down it doesn't look all that bad. I welded two pieces 1/4 x 3 12 " long side by side but with no space or bevel, welded 8" one side and pounded it to deform seriously without failure of weld.

[AKweldshop]

AC.

[MinnesotaDave]

how do you run a tig torch DCEP????
I had my leads swiched one day, and "boom", went off like a firecracker inside the tig cup.
how do you do it?

~John

I tried it again reverse polarity with 1/8" thoriated on 1/4". It balled up the tungsten fast. I could weld, but not well. I got a lot of black, I think so much turbulence from the torch it was sucking in air.

Switching to straight polarity EN I don't see what the fuss is about. It is necessary to force the rod in, breaking under the slag that looks like the scummy layer that forms on liquid lead when making bullets for muzzle loader. After it cools it isn't quite as pretty as AC, but brush it down it doesn't look all that bad. I welded two pieces 1/4 x 3 12 " long side by side but with no space or bevel, welded 8" one side and pounded it to deform seriously without failure of weld.

Bill, DC+ tig welding is only for very thin aluminum. Notice my posts where I list 1/8" tungsten will only handle about 40 amps?

[Bill Beauregard]

how do you run a tig torch DCEP????
I had my leads swiched one day, and "boom", went off like a firecracker inside the tig cup.
how do you do it?

~John

I tried it again reverse polarity with 1/8" thoriated on 1/4". It balled up the tungsten fast. I could weld, but not well. I got a lot of black, I think so much turbulence from the torch it was sucking in air.

Switching to straight polarity EN I don't see what the fuss is about. It is necessary to force the rod in, breaking under the slag that looks like the scummy layer that forms on liquid lead when making bullets for muzzle loader. After it cools it isn't quite as pretty as AC, but brush it down it doesn't look all that bad. I welded two pieces 1/4 x 3 12 " long side by side but with no space or bevel, welded 8" one side and pounded it to deform seriously without failure of weld.

Bill, DC+ tig welding is only for very thin aluminum. Notice my posts where I list 1/8" tungsten will only handle about 40 amps?

Yeah, I know, but the man posed the question; was it possible. I remembered trying it to see what happened, then couldn't remember for sure, polarity. So I tried again. Reverse polarity was not going to work, too much heat on the tungsten. Straight polarity worked reasonably well. I had to really push to get filler beneath the seemingly thickened, and toughened oxide layer, but was surprised how easy and quick it welded. I shined it up with a wire brush, it didn't look all that bad. I beat it up, it didn't break!
I just noticed your 40 amp with 1/8" tungsten. I trust you are referring to EP?
There is no chance I,ll ever use it. But the soothing nature of a DC arc is sort of therapeutic. I still prefer aluminum over steel, deterioration to scrap doesn't begin immediately. Living in the North it's heartbreaking to see a new truck reduced to landfill in about 5 years. One day I'll build a Jeep body of AL.

[Bill Beauregard]

I have two small pieces of aluminum to join. I have been considering options like soldering (with Alumiweld), stick (with E4043) or TIG. I know that aluminum TIG is normally pulsed to allow for surface cleaning. My multi-process welder has TIG DC- without pulse. Do you think I could do this small aluminum job with DC+? I'm thinking DC+ to keep more heat on the tungsten.

Do you weld air frames? or is that an unrelated avocation?

[MinnesotaDave]

I tried it again reverse polarity with 1/8" thoriated on 1/4". It balled up the tungsten fast. I could weld, but not well. I got a lot of black, I think so much turbulence from the torch it was sucking in air.

Switching to straight polarity EN I don't see what the fuss is about. It is necessary to force the rod in, breaking under the slag that looks like the scummy layer that forms on liquid lead when making bullets for muzzle loader. After it cools it isn't quite as pretty as AC, but brush it down it doesn't look all that bad. I welded two pieces 1/4 x 3 12 " long side by side but with no space or bevel, welded 8" one side and pounded it to deform seriously without failure of weld.

Bill, DC+ tig welding is only for very thin aluminum. Notice my posts where I list 1/8" tungsten will only handle about 40 amps?

Yeah, I know, but the man posed the question; was it possible. I remembered trying it to see what happened, then couldn't remember for sure, polarity. So I tried again. Reverse polarity was not going to work, too much heat on the tungsten. Straight polarity worked reasonably well. I had to really push to get filler beneath the seemingly thickened, and toughened oxide layer, but was surprised how easy and quick it welded. I shined it up with a wire brush, it didn't look all that bad. I beat it up, it didn't break!
I just noticed your 40 amp with 1/8" tungsten. I trust you are referring to EP?
There is no chance I,ll ever use it. But the soothing nature of a DC arc is sort of therapeutic. I still prefer aluminum over steel, deterioration to scrap doesn't begin immediately. Living in the North it's heartbreaking to see a new truck reduced to landfill in about 5 years. One day I'll build a Jeep body of AL.

You're right, he asked can it be done on DCEP. I usually jump to the conclusion a person means can it be done well - and for very thin pieces of aluminum the tungsten can handle it Which I always find interesting since manufacturers of DC only inverters don't list that capability and it worked so well when I tried it I think they should.

On DCEN with 100% helium the theory goes that deep penetration and high travel speeds are achieved with less amperage than on AC. This one I have not tried, but have been shown samples by those that have, that prove the theory. Pushing through the scummy oxide layer was also noted.

You are correct about my amperage listing, 1/8" tungsten, 40 amps DCEP (way less than AC or DCEN), I went back and added that to make it more clear.

I think aluminum is cool and an aluminum jeep body would be even cooler . ...salted roads suck....

[lazerbeam]

Some inverters do not have the capability to weld DCEP because the shielding gas comes through the DCEN side and you only have the option to switch to AC welding. If you plug in the tig torch to the + side then you will not have shielding gas and your tungsten will pop as soon as you light up.

[Superiorwelding]

This video might help you out.
http://www.youtube.com/watch?v=lqXSHdRbOG0