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.

[dazza]

CO2 is an active gas and gives better penetration than Argon mixes. 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.

birchy ive used up 100,s of bottles of argon as a former welder fabricator with variuos fab shops much nicer welds with argon ,the co2 is crap and commonly used in the car trade and back street garages in my neck of the woods at least, i scored a fair bit of it from them for side work from home, both will do the same job but theres a noticable difference between the two when using it.

[magicniner]

MIG ......... It's ideal for mild steel down to 2mm - 3mm thick. Anything less than 2mm thick will be best welded with TIG.

That's innacurate information and as a former Vauxhall Dealership Panel Beater and Jig Operator I can inform you that body steel down to 0.8mm is easily welded with MIG and CO2, ESAB set bodyshop proceedures for this using 0.8mm wire, thinner material than this is better welded with 0.6mm wire, some good MIG sets designed for lighter work will have an intermittent setting to help welders who are unable to deal manually with thin material,
Regards,
Nick

[birchy]

That's innacurate information and as a former Vauxhall Dealership Panel Beater and Jig Operator I can inform you that body steel down to 0.8mm is easily welded with MIG and CO2, ESAB set bodyshop proceedures for this using 0.8mm wire, thinner material than this is better welded with 0.6mm wire, some good MIG sets designed for lighter work will have an intermittent setting to help welders who are unable to deal manually with thin material,
Regards,
Nick

I didn't say it CAN'T be done. For "on the bench" type work, TIG does a nicer job of sheet metals and gives better pool control, particularly for none-expert welders. I also said that thinner materials could be welded but you generally have to "spot" weld to avoid burning through if you're not an expert. I've welded cars with an arc welder in the past but I wouldn't recommend it.