Mig or ARC Welder... What should i go for?

[birchy]

I'm a City & Guilds 229 I, II & III qualified welder and fabricator and used to work for a company who build steel bridges, electric pylons, sub stations, etc. I've owned an Oxford 180A mig for at least 15 years, am a ham-fisted bugger and have made more gates and wrought iron work than I care to remember. It takes 15Kg spools of wire and I'm currently on spool number 5 or 6. Other than replacing a couple of tips, the trusty old Oxford hasn't had any new parts and just plods on forever and ever. I very rarely need the full 180A but even when I do, it can still lay about a metre of continuous 6mm fillet before it cuts out on overheat. I can only remember a few occasions where I actually worked it so hard it needed a 10 minute cool down.

Stick a reel of 0.8mm wire on it and get a bottle of CO2 from a pub or pub gas supplier. It'll be "food grade" CO2 if you get pub/fizzy drinks gas so it will be guaranteed pure. Argoshield does give a slightly better weld finish but CO2 costs £10 a bottle and no rental...