MIG Stainless

[Ironcrow]

I've been welding mild steel with my Millermatic 231 MIG, C25, and 0.030 solid wire. I want to get set up to weld some 0.062 304 stainless sheet. I just need weld the corners on some boxes. There's a whole bunch of them, so it will be worth getting set up well (but not so many that I can afford to buy a different welder). So, do I just get some 0.023 stainless wire, tri-mix, and spark away?

 

[dr_clyde]

Pretty much. I would be leery about wire welding stainless that thin, so I would get some copper bars and back the welds with them as a heat sink and burn through protector. 16 GA is pretty thin stuff to seam with a MIG on a good day, stainless just adds to the frustration.

Sure you don't have a buddy with a TIG you can slip a case of beer?

 

[offroadsteve]

I have seen procedures for stainless MIG, but i'd agree with Dr Clyde, 1/16" is pretty thin for MIG.

Gas wise I would use 98% Argon, 2% O2.

 

[zkling]

That is not going to be fun no matter which way you cut it, especially with a conventional mig machine. How long do each of the beads need to be? Yes your approach is correct. Depending on the project I'd make a back gassing/support fixture to prevent burn through and oxidation on the backside. If you have been looking for a challenge, you found a good one. The hardest is going to be your start and stop points. Have you priced out a full size spool of 308L or the like recently?

 

[Ironcrow]

They are shallow little pans about 1 inch deep, the 1 inch seam is welded completely. I'll try one and see how it works. I have a friend with a bottle of tri-mix, so I'll experiment with that first.

 

[Ironcrow]

Ha! False alarm. Client has decided to switch to mild steel, a little heavier, weld, and paint. Cost cutting...

I'd still like to learn about welding stainless, so I'll look for opportunity to experiment. Thanks for the help.