tried dc positive tig welding

chubbysautocenter · Wed May 28, 2014 8:47 am

first time doing this and very disappointed.
put the stinger on the positive side and the ground on the negative side
and as soon as i stomped the pedal my tungsten balled up huge. not only that smoked my glass lens and cracked it.
what did i do wrong?

MinnesotaDave · Wed May 28, 2014 9:16 am

DC+ is only used for very thin aluminum.
The tungsten can't take that kind of heat - for example, 1/8" tungsten only handles about 40 amps on DC+
But on DC- it handles hundreds of amps.

AKweldshop · Wed May 28, 2014 12:33 pm

chubbysautocenter wrote:first time doing this and very disappointed.
put the stinger on the positive side and the ground on the negative side
and as soon as i stomped the pedal my tungsten balled up huge. not only that smoked my glass lens and cracked it.
what did i do wrong?

Why would you try it???
What material where you attempting to weld?

Wed May 28, 2014 6:02 pm

Since this showed up in the "forum instructions", I'll migrate it to the TIG forum. I'll certainly get more views there.

Steve S

chubbysautocenter · Wed May 28, 2014 7:13 pm

MinnesotaDave wrote:DC+ is only used for very thin aluminum.
The tungsten can't take that kind of heat - for example, 1/8" tungsten only handles about 40 amps on DC+
But on DC- it handles hundreds of amps.

thanks that's great info

chubbysautocenter · Wed May 28, 2014 7:14 pm

AKweldshop wrote:
chubbysautocenter wrote:first time doing this and very disappointed.
put the stinger on the positive side and the ground on the negative side
and as soon as i stomped the pedal my tungsten balled up huge. not only that smoked my glass lens and cracked it.
what did i do wrong?
Why would you try it???
What material where you attempting to weld?

just testing it out. it was mild steel

RichardH · Thu May 29, 2014 2:54 am

chubbysautocenter wrote:
AKweldshop wrote: Why would you try it???
What material where you attempting to weld?
just testing it out. it was mild steel

Now you know, and you won't forget.

I learned it the same way.

Heat flows toward the positive conductor. In this case, it went from the steel into your tungsten.

Generalizations... The torch is negative for steel (aka DC- or DCEN [electrode negative]) and AC for aluminum. With aluminum, the positive swing (DCEP) on the AC cycle burns off the oxide layer, at the expense of heating your tungsten and reducing the heat that goes into the joint (which is one reason aluminum needs a beefier welder for the same thickness).

Cheers,
Richard

chubbysautocenter · Thu May 29, 2014 4:27 pm

RichardH wrote:
chubbysautocenter wrote:
AKweldshop wrote: Why would you try it???
What material where you attempting to weld?
just testing it out. it was mild steel
Now you know, and you won't forget. I learned it the same way.

Heat flows toward the positive conductor. In this case, it went from the steel into your tungsten.

Generalizations... The torch is negative for steel (aka DC- or DCEN [electrode negative]) and AC for aluminum. With aluminum, the positive swing (DCEP) on the AC cycle burns off the oxide layer, at the expense of heating your tungsten and reducing the heat that goes into the joint (which is one reason aluminum needs a beefier welder for the same thickness). great info thanks

Cheers,
Richard