High Frequency DC TIG and Aliminum

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I know AC gives substantially better results over DC in the GTAW process when welding aluminum, but I was curious if the addition of a high high frequency start setup on a DC rig would make it perform any when trying to join the metal. Anyone happen to know?
Reply:No, High frequency is just an arc starting mechanism. AC works because the electrode positive component cleans the oxides off the metal and the negative component provides the heat. In DC you can go either electrode positive or electrode negative but not both. It is possible to marginally weld aluminum on DC negative is you use 100% helium as the shielding gas, but helium is super expensive and the welds turn out rather poor. Just bite the bullet and buy an AC/DC TIG if you want to weld aluminum.Miller Multimatic 255
Reply:Yep. Well said, Louie.
Reply:Thanks for the feedback about HF and AL. I suspected it wouldn't matter much, if any...Jodie over on YouTube had some success using AL stick welding rods on DCEN with argon (I'm assuming, he didn't mention helium) with a pre-heat. It didn't look like he wire brushed with stainless beforehand, so perhaps his results would have been even better. I'm just a hobbyist, not planning on doing anything structural and the high cost of AC rigs, even used, these days just doesn't warrant the expense for me. I'd even consider using those zinc-ish soldering/brazing rods with DC TIG in spots where using a propane/MAPP torch might not be advisable. On that note, a couple of YouTubers have actually done some poor man's tensile strength tests on joints filled with the stuff and it is pretty impressive for what it is.Last edited by weldbro; 1 Hour Ago at 02:17 AM.
Reply:

Originally Posted by weldbro

Thanks for the feedback about HF and AL. I suspected it wouldn't matter much, if any...Jodie over on YouTube had some success using AL stick welding rods on DCEN with argon (I'm assuming, he didn't mention helium) with a pre-heat. It didn't look like he wire brushed with stainless beforehand, so perhaps his results would have been even better. I'm just a hobbyist, not planning on doing anything structural and the high cost of AC rigs, even used, these days just doesn't warrant the expense for me. I'd even consider using those zinc-ish soldering/brazing rods with DC TIG in spots where using a propane/MAPP torch might not be advisable. On that note, a couple of YouTubers have actually done some poor man's tensile strength tests on joints filled with the stuff and it is pretty impressive for what it is.