TIG On Aluminium

[Mr shiney]

Practising with my new on AC mode...... Not done much aluminium outside of C&G1.
Managed to vaporise 2 ceramics. I was using a 1.6mm 2% Thoriated Tungstenand 1.6mm filler on a piece of 6mm chequer plate and the tungsten just vanished in a splatter of dirty smoke and left the ceramic glowing red pretty much on striking the arc. I tried a variety of amps from 55 to 120.

Any thoughts on what I was doing wrong?

I then set it up at 65amps on a piece of 1.6mm with the same set up and ran some nice beads. I am thinking I might stick a pedal on though as trying to lower the amps as the material heats up with the torch mount adjuster is a pain in the ass!!

 

[Wendelspanswick]

Practising with my new on AC mode...... Not done much aluminium outside of C&G1.
Managed to vaporise 2 ceramics. I was using a 1.6mm 2% Thoriated Tungstenand 1.6mm filler on a piece of 6mm chequer plate and the tungsten just vanished in a splatter of dirty smoke and left the ceramic glowing red pretty much on striking the arc. I tried a variety of amps from 55 to 120.

Any thoughts on what I was doing wrong?

I then set it up at 65amps on a piece of 1.6mm with the same set up and ran some nice beads. I am thinking I might stick a pedal on though as trying to lower the amps as the material heats up with the torch mount adjuster is a pain in the ass!!

A pedal is much easier to use, it's rare that I don't use mine, normally when in an awkward position and I have no other option than to resort to the torch trigger.
As a guide match your Tungstens to your material thickness on smaller gauge material.

 

[BrokenBiker]

I would be using a 2.4mm tungsten and rod on 6mm plate. the torch mounted adjusters are horrid things, only used one once, never again. I use a pedal if using my mates ac/dc tig, but apart from that I have only ever had lift arc so stuck with the current I set it at, just move a bit quicker when it gets hotter

 

[langy]

You should be using at least a 2.4 tungsten and of the white, grey or blue flavour

 

[hotrodder]

Doesn't explain the vaporised tungsten and glowing cup but thoriated is the wrong flavour for AC, it can work but doesn't melt or 'ball' cleanly usually and is very prone to splitting (and contaminating the weld) from the thermal shock. Any other flavour is fine for both AC & DC

120A shouldn't be enough to destroy even the wrong flavour of 1.6mm tungsten unless the AC balance is heavily biased towards EP (electrode +ve for "cleaning") or the polarity is wrong which'd make the AC balance work 'backwards'. As said be better with a 2.4 tungsten, personally i step up at around 90 - 100A with AC usually and a 2.4 does me through to the machines max of 200A although AC balance settings can make quite a difference to the amperage a tungsten will take

 

[Mr shiney]

So was I overloading the tungsten trying to use it on thick stuff? I am using the Blue and Grey Tungstens.

 

[Mr shiney]

Doesn't explain the vaporised tungsten and glowing cup but thoriated is the wrong flavour for AC, it can work but doesn't melt or 'ball' cleanly usually and is very prone to splitting (and contaminating the weld) from the thermal shock. Any other flavour is fine for both AC & DC

120A shouldn't be enough to destroy even the wrong flavour of 1.6mm tungsten unless the AC balance is heavily biased towards EP (electrode +ve for "cleaning") or the polarity is wrong which'd make the AC balance work 'backwards'. As said be better with a 2.4 tungsten, personally i step up at around 90 - 100A with AC usually and a 2.4 does me through to the machines max of 200A although AC balance settings can make quite a difference to the amperage a tungsten will take

I think I had the AC balance on around 65%, and the Ac at 120z.

 

[hotrodder]

65% what? 65% EN is about right but not all machines display AC balance as EN, some do it the other way around and 65% EP would explain the mess

Blue is 2% lanthanated or a mixed flavour. Grey is ceriated and 2% thoriated are red.

 

[Mr shiney]

Wave balance says at the 10% end its penetration and the 65% end maximum cleaning. AC frequency goes up to 150.

 

[langy]

So was I overloading the tungsten trying to use it on thick stuff? I am using the Blue and Grey Tungstens.

??? in the first post you said "I was using a 1.6mm 2% Thoriated Tungsten"

 

[hotrodder]

Wave balance says at the 10% end its penetration and the 65% end maximum cleaning. AC frequency goes up to 150.

Penetration = biased to EN, cleaning = more EP. Around 2/3 of the total heat occurs at the +ve electrode i.e. it's sounding like the tungsten vaporised and made a mess 'cause the AC balance was set wrong

 

[Mr shiney]

??? in the first post you said "I was using a 1.6mm 2% Thoriated Tungsten"

Sorry, I meant Ceriated and Lanthanated! grey and Blue!!

 

[Richard.]

Wave balance says at the 10% end its penetration and the 65% end maximum cleaning. AC frequency goes up to 150.

Forget about the frequency at the moment it's not causing your problem. 2 polarities en ep.
Dc Tig requires en 100% to take the heat out of the tungsten and into the work peace there for (tungsten dependent) you should maintain the point. In ac it fluctuates between the 2 polarities to break through the oxide layer and give you the cleaning Alu requires. Ac balance is the % of the wave spent in a particular polarity. You need just enough cleaning(Dcep) set to ensure the weld is coming out nice and shiny and no more. The rest is all penetration (dcen) this should be around 65-75% dcen. By heading deeper into the cleaning zone your loading that tungsten up and it will disappear. Up to a 100 amps I'm happy with a 1.6 over that I go 2.4

 

[chunkolini]

I think I will give that one a miss. Too complicated.

 

[Mr shiney]

Forget about the frequency at the moment it's not causing your problem. 2 polarities en ep.
Dc Tig requires en 100% to take the heat out of the tungsten and into the work peace there for (tungsten dependent) you should maintain the point. In ac it fluctuates between the 2 polarities to break through the oxide layer and give you the cleaning Alu requires. Ac balance is the % of the wave spent in a particular polarity. You need just enough cleaning(Dcep) set to ensure the weld is coming out nice and shiny and no more. The rest is all penetration (dcen) this should be around 65-75% dcen. By heading deeper into the cleaning zone your loading that tungsten up and it will disappear. Up to a 100 amps I'm happy with a 1.6 over that I go 2.4

Thanks Richard, that makes more sense now. So ideally if I set the balance to around 35% which is the penetration DCeN side it should improve things?

I will have a try this morning!!!

 

[Richard.]

No you set the balance 30-35% ep or 65-70% en
Cleaning should be the lower % and penetration the higher%.

 

[Richard.]

What machine have you got. I'll google the front panel and tell you where I would roughly set the balance control.

 

[Mr shiney]

Its the Thermal Arc 202 ACDC

 

[Mr shiney]

I just looked in the book and it says the maximum weld penetration is at Wave Balance 10% and maximum cleaning is at Wave Balance 65%

 

[Richard.]

It says it's range is between 10-65% EN which I don't find to be a helpful range. I'd go with the maximum at 65% en, the adjustment is a pretty useless range unless I'm understanding it wrongly. Mine has a range of 50-85% en which is far better because I usually work right in the middle of it and have a good bit of adjustment either side. Antonio has the same machine might be worth a pm to see if he understands the range better. If it's how I think it is set it max en and see how that goes.