TIG or MIG welder

[birchy]

I've been fabricating for 22 years, so can shed some light on this much asked question. MIG is by far the easiest to learn and cheapest to run. It's ideal for mild steel down to 2mm - 3mm thick. Anything less than 2mm thick will be best welded with TIG, although MIG can be used if you "spot" weld to avoid burning through. Basically, use MIG if you're going to be building steel frames and welding thick(ish) materials and use TIG for anything like sheet metals, etc. TIG is also preferred for Stainless Steel and Aluminium, although MIG can also be used with the correct equipment and set up. Note that for Aluminium, you will need a welding set with an AC setting. These don't come cheap and will generally double the price of a standard machine. Buy decent quality kit. The Chinese welders on ebay aren't up to much I'm afraid. SIP and R-Tech are 'OK' brands...made in China but are of a decent standard and (more importantly) have UK based customer support, servicing and spare parts. For good machines, I recommend Oxford which are UK built. I've had my Oxford 180A MIG set for 20 years and it's never let me down despite heavy use.

TIG uses a LOT more gas than MIG and requires pure Argon which ain't cheap, so running costs are much greater vs MIG. For MIG, I've used CO2 "pub gas" for many years without any issues. Technically we are MAG welding because CO2 is an active gas and gives better penetration than Argon mixes. The only thing to be aware of is that you must get the fizzy drinks CO2 as it is pure, whereas the beer gases will have nitrogen, etc in them. At £10 a bottle, no deposit and a lifespan of several years, it's a no brainer. There's a bit of an urban myth going around that CO2 is crap but very few (if any) of the "welders" saying it have actually used CO2.