Mig welding stainless and choice of Mig wire?

Want to **** weld some stainless tubing for an exhaust but i want the welds to be able to be brush polished like the tubing im welding. I do not have a tig

Is there a specific wire spool i can buy for my Mig that will let me do so

Also is 75/25 co2 and argon the proper sheilding gas

 

I dont know if there are several different kinds of stainless wire... to tig stainless you use argon gas. Maybe and probably the same to mig it.

 

What stainless is it (316, 308. etc)? You match the wire to that, and I think you should use a tri-mix gas.

 

Agree with the guy above me on matching the stainless... If you got the tri gas just go practice with it and see how it works.

 

I've always used pure argon when Migging stainless, because it was already there on the Tig rig. It worked. Not to sy something else wouldnt be better, but it wasnt worth it to get a special gas for a small project.
Definitely paractice on similar material. If the heat and feed arent right it will black up on you and not polish out.
If you are that worried about appearance, Tig is your best bet, the Mig only gives you a little speed.
Good Luck!

 

You might be better off in this case to tack it together with the mig and then take it to someone who can tig it. I know guys who are damned good with a mig on stainless who still would tig weld stainless tubing every time. All there would be was actual welding time and material and no fitting up time to pay for that way.

 

We have a Miller p***port that we only use for stainless. We use 316L wire, it works fine for any 304, 308 or 316. We have found that tri gas is way better than Argon, but used Argon for years before we actually tried it, so it will work for you as well. The trigas is expensive,but well worth it if you have alot of stainless to do.

 

Probably the best advice you've had so far.

 

A guy around the block from me MIG welds stainless and buffs it up and you can't tell. I don't know what wire he uses, but I do know for sure you can use a MIG and end up with a nice polished surface if you sand/file/grind down the bead carefully.

 

You can do it, I bought my stainless wire at the TSC store (tractor supply) 25 ga. Uses argon mix 25-75. Used 3" 304 stainless pipe and fittings i rescued from my sons s**** dumpster. He owns a pipe fitting company that primarily does pharmaceutical work. He told me to tack it together and bring it to him to have one of the guys tig it up. But he lives several hundred miles away and I'm one of those guys that do everything the hard way.
Like I said it can be done lots of grinding. First picture on the 55 I made everything from the header back. Ground smooth and finished with Scotch-Brite disc. The next two pictures are a set I just made for my latest 55 project under the ch***is headers.
By far the best way to do it is tac it up and have someone tig it. Unless your a old do it yourself guy like me. Ron.
. .

 

If the Tri-Gas is 90% Helium, 7.5% Argon, and 2.5% CO2 than that is the right stuff. Stainless is nice to weld, have fun!

 

You can use pure argon, tri-mix is more for food grade.

 

Besides, good luck getting helium. Cheaper to buy a car, let it sit for 20 years, then sell at a loss, than pay for helium today.

I agree on the 'tack, then pay a shop to TIG' brigade.

Cosmo