Cut the gas off on the mig when you can lay a bead without it then you can weld and may turn the gas back on. All the parts to replace are available.
Nope
.. a welding wire designed for use with shielding gas cannot be used without shielding gas, no matter how "good' a welder you are, well, unless you perhaps have divine intervention
or if you perhaps live in an atmosphere free "vacuum".
With semi-automatic mig welding the shielding gas "shields" the weld from the atmosphere. Flux core wire and manual stick welding uses a flux that covers the weld...
Take away the shielding or the flux and you end up with severe porosity.
