I'm thinking of buying a MiG welder. All my previous welding was done with acetylene and huge bottles! Advice on purchase would be helpful please. Are the 'no gas' systems any good? What size machine is appropriate for chassis, body and bumper/spotlight brackets/tow bars etc. When the description states 'needs hard-wiring' I assume that's because a standard 13A plug can't take the current. I could hard-wire with 'twin and earth' but the machine needs to be portable so I can weld on the drive?