yep those inverter scratch start tig/stick welders are great and portable for small jobs. Its carrying a "L" size argon cylinder that kills the portability! You can get "high"pressure disposable canisters now that hold enough gas to do a small job.
My little inverter will run a 5mm rod and is lighter than a couple of bricks.
I would probably attack that repair with the MIG anyway, welly the weld in there and cool it before it jiggers the seals, then attack it with a 4" grinder to finish it before a skim of filler and a coat of paint.