[Aussie Mike]

Hi David,

In my experience gasless MIGs don't produce as clean a looking weld with a lot more weld spatter.

You might find that some of the small/medium MIG welders support both gas and gasless wire. I think it's only a change of polarity to go gasless. There are also some disposable gas canisters available which might work out cheaper if you don't use it much.

One thing I will say is once you have a welder you will always be finding jobs for it. You may only plan on a few jobs initially but new jobs always pop up. ie welding up gates, trailers, general repairs etc, you would be surprised.

I have a 200A MIG and a 125A TIG and run a bottle of Argon and a bottle of Migshield gas with rentals for the two "E" size bottles. I use the Argon with the TIG and with the MIG when I do aluminium. The Migshield is just for welding steel with the MIG. I use maybe 1 refill of each per year so the rental costs me more than the gas. However I pay it because I like the performance of the MIG running gas. The TIG has to run Argon no matter what you weld.

Straight CO2 is fine for mild steel only but i don't think it performs as well as a mixed argon CO2 gas like migshield. The carbon in the CO2 has some effect on the metalurgy of the weld. It's not worth the smalll saving as the cost of the gas is the least of your wories when you are paying $120 a year for the bottle rental. I've been looking into using straight argon for everything and getting rid of one bottle. Unfortunately I can't get a straight answer from any of the gas or welding companies on what kind of weld performance it give with mild steel. When I get some spare time I'll do a bit of experimenting and compare the two in some controlled tests.

I would buy a MIG over a TIG because there's a lot more you can do with a MIG for general purpose welding. It's a lot faster too. If you want to weld aluminium with a TIG you will need to spend a fair bit of cash to get a unit that does AC since most of the smaller units are DC only. DC is fine for steel and stainless but it makes a mess of aluminium.

Give me a call if you have any questions or if I can give you any pointers.

Cheers