I bought a TIG welder thinking I was going to do a little repair on the hell hole and have found that TIG needs a lot of technique. I'm getting ok on the bench but the combination of thin sheet metal and out of position welding on the car has lost my confidence. Anyway, I think I have to go with MIG....My question is can I weld MIG with the pure argon gas that I use with the TIG welder or do I have to buy another bottle? I understand that most MIG is done with a mixture of argon and co2. I would like not to buy another bottle. What do you think?

Thanks,
Bill

Argon/Co2 is cheaper. Pure argon may be a better shield gas for thin stuff. For thick stuff you can get away with (dirt cheap) pure Co2.

I think pure argon should only be used for aluminum, actually...

the rest is a mix

Argon is for stainless and aluminum, with MIG. I'm told you can get by using it for regular steel, but I haven't tried it. There's no harm in giving it a try on some scrap.

I'm just trying to get out of paying for the extra tank. I haven't got the MIG welder yet. Some of the welders that are available used come with the gas bottles and I'm just trying to figure out the most economical approach and still get a good structural weld.

Thanks for the help,
Cheap Bill

My mistake:

"Pure inert gases such as argon and helium are only used for nonferrous welding; with steel they cause an erratic arc and encourage spatter (with helium) or do not provide adequate weld penetration (argon). Pure carbon dioxide, on the other hand, allows for deep penetration welds but encourages oxide formation, which adversely affect the mechanical properties of the weld. Its low cost makes it an attractive choice, but because of the violence of the arc, spatter is unavoidable and welding thin materials is difficult. As a result, argon and carbon dioxide are frequently mixed in a 75%/25% or 80%/20% mixture, which reduces spatter and makes it possible to weld thin steel workpieces."

Hi pure argon will work, but you will get better results with 75/25 (75% argon + 25% CO2) . Good Luck Bob

It will work, but it's costlier, and not ideal.

BJH

I wouldn't use any gas, buy a spool of 035 flux core or core shield wire get some 040 tips and get rid of the cup on the end of the gun make some practice passes on some light gage sheet metal and adust your heat and speed settings you will get a little spatter but you don't have to worry about any gas. I weld sheetmetal quite often and in some very awkward positions. Also get some cheap ear plugs, there's nothing more annoying than hearing some earwax sizzling and you can't move fast enough to get it out, trust me on this one

I believe that is the 1st person i have ever heard recomend using flux core wire over shielding gas

Flux core has it's uses (thicker materials, at the edge of your welders capabilities) but sheetmetal work is not one of them.

BJH

QUOTE (Crazyhippy @ Feb 15 2006, 03:39 PM)

I believe that is the 1st person i have ever heard recomend using flux core wire over shielding gas Flux core has it's uses (thicker materials, at the edge of your welders capabilities) but sheetmetal work is not one of them. BJH

Fluxcore does an adequate job but it's very rough. Great penetration for thicker metals and it really burns through rust and crap (great for 'field repairs'). I wouldn't recommend fluxcore for sheetmetal, but it will work.

As for the original question - if you already own the pure argon, use it, it will work fine. Once that cylinder is done exchange it for Argon/CO2. It works better for MIG and it's cheaper.

flux-core may be fine for exhaust, where no one will ever see the weld... but even then, if you CAN use gas, why not have a nice weld?

When I welded king crab pots for a living, I did a "show" pot with pure argon for prettier welds. This was on 1/1/2" thick bar stock...plenty of penetration. No worries at all with sheet metal...just weld as hot as you can.

John www.ghiaspecialties.com

I actually use straight CO2 for all my mig.
(even once on some stainless exhaust)

its not answering the original question.
and its not ideal.
but it promotes better penetration.

I think to answer the original question...
any of the above can work, and if you already have it you can use it.

brant