Nice! I have a feeling that's the route this is going to go...For that tank repair I doubt TIG is a valid option given the condition of the material. After sand blasting put some tape over the hole (on the outside just to be clear) then apply the JB Weld to in interior of the tank. You can press a piece of window screen wire into the JB if you feel you need additional strength. After the JB fully cures you may need a bit of filler to smooth out the edges but you may get by with a simple sand and paint.
Here is a flywheel cover I repaired that way.
Hopefully - have to start hunting around or put a request out on nextdoor or something. If I go to a company that does that in this area, they'll charge an arm and a leg just to walk in the door. I keep eyeballing a cabinet at horror freight, but I've only got a 30 gallon compressor, which of course means I'll "have" to buy a larger compressor...That's the only way I would approach prepping that tank for repair regardless of your patching method. Shouldn't cost much to have it done if you don't want to spend the money on your own setup.