03-22-2015, 10:21 PM
I've built a couple of car exhausts in stainless with MIG. I've never seen flux-core stainless wire (not saying it doesn't exist, however). If you're using a gas set up, you have to run pure argon. Second, unless you're "back-purging" (i.e. shielding the back of the weld with argon) you really must use SolarFlux on the back side of the welds.
http://www.solarflux.com/index.html
The MIG welds look like ass -- spatter everywhere, and badly oxidized -- but they held up. You can't really do pre- and post-flow with MIG, and even with the CFH cranked up, I couldn't get enough gas around the weld (at least with my MIG machine, which is not a pro-grade machine) so there's always going to be oxidization.
TIG is superior, but that's not the question you asked. I actually like using the stainless MIG wire as filler for TIG when I'm doing fussy stainless jobs.
http://www.solarflux.com/index.html
The MIG welds look like ass -- spatter everywhere, and badly oxidized -- but they held up. You can't really do pre- and post-flow with MIG, and even with the CFH cranked up, I couldn't get enough gas around the weld (at least with my MIG machine, which is not a pro-grade machine) so there's always going to be oxidization.
TIG is superior, but that's not the question you asked. I actually like using the stainless MIG wire as filler for TIG when I'm doing fussy stainless jobs.