Page 1 of 1
Tungsten contamination
Posted: Mon Jan 07, 2019 1:46 pm
by 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
Re: Tungsten contamination
Posted: Tue Jan 08, 2019 12:15 am
by 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
Re: Tungsten contamination
Posted: Tue Jan 08, 2019 1:53 am
by tweake
probably more common caused by bad tungsten or snapping it rather than cutting it.
Re: Tungsten contamination
Posted: Tue Jan 08, 2019 7:22 am
by cj737
tweake wrote: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

Re: Tungsten contamination
Posted: Tue Jan 08, 2019 7:37 am
by 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.
Re: Tungsten contamination
Posted: Tue Jan 08, 2019 8:55 am
by 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.
Re: Tungsten contamination
Posted: Sun Jan 13, 2019 4:59 pm
by 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.
Re: Tungsten contamination
Posted: Sun Jan 13, 2019 5:30 pm
by 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 1475 times
Often a regulator gauge can't be trusted. These are cheap from fleabay etc.
Re: Tungsten contamination
Posted: Mon Jan 14, 2019 1:08 am
by 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.
Re: Tungsten contamination
Posted: Mon Jan 14, 2019 4:39 am
by 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.