[falconav8r]

I have been trying different tungsten for aluminum welding. 2% lantanated, 2% ceriated, 2% thoriated. 2% thoriated has always been the go to, however after welding for a few minutes the tungsten does not keep the shiny ball end, instead it seems to split and appears contaminated. The aluminum is very clean, acetone wiped on project as well as the rod itself. 1/8" aluminum, 20 CFH argon, 145 amps max on foot pedal, with or without pulse. Weld quality and appearance is excellent but tungsten always needs regrinding

[weldin mike 27]

Hi there, this can happen due to contamination of the shielding gas itself, or a pin hole leak in the line, drawing in air. Try a different welder with the same bottle or a different bottle that's known to be good. Also too, the tungsten stick out can be critical if not using a gas lens, don't have more than 6mm of stick out

[tweake]

probably more common caused by bad tungsten or snapping it rather than cutting it.

[cj737]

probably more common caused by bad tungsten or snapping it rather than cutting it.

...and a too sharp grind angle, or your AC Balance is set too high. Set it above 75% and watch it tear a tungsten into shreds

[LtBadd]

well 2% thoriated will deform when welding on AC, it's not for AC welding and there is no way around that. Lets see a pic of this contamination.

[falconav8r]

Thanks for the answers to my question. I forgot to mention I am using a #7 gas lens, A/C balance 35%. Changed the argon and the difference was immediate.

[falconav8r]

Still having the same issue. Aluminum is very clean, AHP Alphatig 200DX, A/C balance 35 - 40, Frequency 75 - 100, 20 CFH argon, 2% Lanthanated or 2% Thoriated, 2% Ceriated 3/32. Same results. See attached pic.

[Coldman]

Check your post flow, should run long enough to keep the tungsten silver.

Also check actual flowrate at the cup with a meter like this:

flow meter.jpg (14.33 KiB) Viewed 1477 times

Often a regulator gauge can't be trusted. These are cheap from fleabay etc.

[tweake]

post flow will help.
i often make that mistake due to being to cheap on the gas.

also tungsten grind. looks like you have a pointy tip. i would flatten that off more. eg make it look more like a crayon.

[noddybrian]

145 amps is on the upper limit for AC in my opinion using 3/32" - I would usually jump up to 1/8" - some batches / brands hold up better.