Cant get a puddle to form on Ally?

[tonys]

Hi,

I have a 160amp AC/DC tig , I have only ever used it for Mild and Stainless steel before. But now want to use it on ally 2mm thick


So I have switched it to AC, got a white tipped tungston set the base current to 100 and the pulse current to 50 , AC feq to around 150 , AC balance to about 50 and the gas was at about 10

When I try to start , the HF start just keeps going on and off like a made one and ally looks like its been hit with a sawn off and no weld puddle forms.

I have cleand it with Acetone, and a stainless brush before hand. I have also tried variouse Power, pulse , AC Feq and AC blanace settings and still get the same results , never get a stead arc ?


Tony

 

[hotrodder]

The results in the pic look typical for no gas or the wrong gas. Presumably you're using pure argon though or you'd have had issues with mild and stainless? What did the tungsten look like afterwards?

The only other things that come to mind are material or machine. Are we talking new aluminium (not coated or anodised) or some random scrap "aluminium"? A machine fault could account for not being to form a puddle but an HF fault or being stuck in DC mode wouldn't explain the black crusty mess

 

[tonys]

Hi hotrodder.

Is a new peice of 5251 2mm thick. The gas is Pureshield Argon, and the tungston was black at the end as if it had got to hot.

Thanks

Tony

 

[Autolupus]

Sounds like the gas is right but not on/blocked or at too low a level to give coverage.
The tungsten doesn't go black from getting too hot, it just melts!

 

[hotrodder]

^^ This. Tungsten discolouration = a gas problem. A lack of post flow can oxidise the tungsten (it's white hot while welding and needs time to cool*) but wouldn't explain the blackened charred ally.

Can you post a pic of a stainless weld? Is gas definately flowing when the machine is in AC? Is the torch correctly assembled* (been a couple of threads where people have assembled the torch **** about face and gotten similar problems)?

*A rough rule of thumb is 1 sec per 10amps, there's more info on gas flow (10 litres/min shouldn't be high enough to cause problems but generally don't need more than 7L/min and too much can be as bad as not enough) and torch assembly in the TIG tutorial/TIG FAQ at the top of the page

Won't have anything to do with your problems but i'd switch the pulse off for now. It's a useful tool for things like thin stainless, less useful on ally and can become a crutch if you don't learn to weld without it

 

[Paul G]

Hi,

I have a 160amp AC/DC tig , I have only ever used it for Mild and Stainless steel before. But now want to use it on ally 2mm thick


So I have switched it to AC, got a white tipped tungston set the base current to 100 and the pulse current to 50 , AC feq to around 150 , AC balance to about 50 and the gas was at about 10

When I try to start , the HF start just keeps going on and off like a made one and ally looks like its been hit with a sawn off and no weld puddle forms.

I have cleand it with Acetone, and a stainless brush before hand. I have also tried variouse Power, pulse , AC Feq and AC blanace settings and still get the same results , never get a stead arc ?


Tony

Hi Tony,

Firstly, I agree with Hotrodder that blackening of the tungsten is indeed a gas coverage problem.
I would set gas post flow to 8 secs as a minimum. I also use a bigger ceramic for ally (16mm i/d) as the arc from the ball end fans out,
unlike a sharp pointed one that you would use on mild or stainless.

Your settings seem a "bit out" too.
With AC the metal only heats up when the electrode is negative so a higher amp setting is needed to compensate for when the
electrode is positive (Cleaning), so up the balance setting to 65/70%.

Again I agree with Hotrodder, but if you must use the pulse then I think you have the setting the wrong way round.
The pulse should be higher than the background.
i.e. 100___/125\__100__/125\__100__ etc.

Does your welder have an HF control switch?
Some have an "off" (for MMA), "on" (for DC TIG), and "Continuous" (AC TIG)
You need continuous HF to maintain the arc for ally.
Some welders automatically go to "HF cont" when you switch to AC TIG.

To sum up, I think you need more amps. It looks to me that the arc is flashing about on the surface without the power to melt it.

Hope this helps.
Cheers,
Paul G

 

[tonys]

Thaks for the reply Paul,

I will give it a go in the morning. I have a plan B now, I did a TIG welding course last year, and funny enought I bumped in to the Tutor in a pub last night , he said I could take it in and he would have a look and see if it me being a prat or its the kit, I half hope its the kit lol

Tony

 

[Shox Dr]

Cool, let us know

 

[tonys]

Hi All
Finally got the time to go down to the local college and as you can see from the image it’s not the kit or me thank god . Fired it up and it worked first time. Had a few tries to make sure it was not a fluke, put it back in the car and took it back to the unit, and bam straight back to the black, crap. So the only thing different is the gas bottle, which is just over a year old now. So I’m going to get a fresh one today. And fingers crossed we will all be good.

Tony