Earl, what kind of thickness were your 6061 fuel tanks? Or maybe worded another way, if a guy was more 'thin gauge' orientated, would there be specific TIG features to look for? When I took my SAIT intro evening course last year (on Miller 2xx?) the instructor was kind of saying some of the 'other' brands like Everlast & models being discussed were actually evolving better boards & controls than some of the established names. But I didn't quite get what knobs & whistles specifically. And then there's aspect of torch handle & assembly. Some apparently offer broader selection of smaller heads & lighter cable/hose & more styles. I'm still not sure myself if handles are brand specific or can anything plug into a box as long as it has XYZ type socket? I got a similar read on some YouTube channels where guys were doing thin gage stuff on import welders. And of course everything on YouTube is 101% real
Peter, the thickest material I work with is .125 with 6061 usually for tanks that will be stationary, for custom fuel tanks on atv's sleds etc i always go to 5052 .063 thick because of its mechanical properties. I chose the Miller Diversion 180 primarily because I needed to start welding and make parts without a lot of experimentation. It's basically the "automatic transmission" of tig welders. The beauty about tig is you can weld thin gauge material without burning through. I've welded 22 gauge (.030) cold rolled steel. Getting back to the Miller, I also chose it because it has high frequency start (vs. scratch start), and it was an inverter based machine. My best advise if your starting out on tig, keep it simple, don't get too caught up on bells and whistles, most any tig setup will weld thin material. Machines are always advancing and I do believe that Miller and Lincoln are the slowest to advance. Everlast, Esab and others are gaining, German made tig and mig welders have unbelievable technologies and addresses a lot of the little annoying things people put up with.
Again keep it simple when your starting out. You don't need a huge selection of collets, cups, torches or tungsten.
My machine came with a W7 torch, I just changed the back cup for a smaller tungsten to get into close areas.
I primarily use one set up, 1/16 2% ceriated tungsten with a #7 gas lens using 75% argon 25% helium mix for my aluminum work. The helium makes any welder on steroids when welding aluminum. Since I only have 110 power supply currently this is a huge advantage. I do have 5 types of filler rod though, for different materials i weld. You can customize most machines with accessories to your liking whether it be brand specific or aftermarket.
The one accessory I plan for mine is a wireless foot pedal that's offered by Miller. Hope that helps.