[Tim Brewer]

Myles, sorry so long to get back to you, I've been out of town. All gas mig machines are switchable. Usually there are directions under the lid telling you how to reverse it. I've never heard of a gassless only mig machine, but I guess there could be. A stick welding machine can do as good a job, but is more difficult to do for most people. Hope this helps,( kinda cool talking to you from New Zealand, some day when i've saved up a whole bunch of cash, i'd love to vacation there someday)
Tim