Hi
I have a gassles MIG which I thought could only weld mild steel, but have been told that I can do stainless or alluminium if I get the right wire is this so??
No.
You can get flux-cored stainless steel wire but this is for heavy industrial use & is used together with a shielding gas.
Aluminium is strictly gas only (pure argon).
If your machine is a dual purpose set you will be able to, by switching polarity & fitting the correct wire/gas.
weldequip