[RST Driver]

Hello everyone,

I am looking for advice on mig welding stainless steel, mainly for light fabrication of exhaust pipes. Although I would really like to have a dedicated TIG welder for these kind of jobs, budget tells me I have to try it with my MIG machine.
In the past I gave it a shot with 82/18 gas (C82, comparable to C75 with slightly less CO2) and pure argon, which - of course - failed miserably. Nevertheless I believe the main problem was my wire: ER308 0.8mm (0.030''). No "Si", no "L", nothing, just plain ER308. I had trouble with burning holes (trying to get a better corner tie in) or a lack of fusion because of an extremely sluggish weld puddle. Amount of spatter was massive and the weld bead was sitting on top of the material or almost falling through. The surface looked dull and grey, far from the light rainbow colour scheme a good mig weld should have.

I have to say that I have zero problems with welding carbon steel. My machine works like a charm and can be dialed in really nicely. No problems with spatter, weak penetration, insufficient corner tie in etc. and a really controllable, wet puddle.
Therefore I guess I have to change my gas and the welding wire. Any recommendations? I thought about getting a bottle of 98/2 Ar/CO2 and a little spool of 0.8mm (0.030'') ER316LSi.

Any tips and tricks are greatly appreciated.
How about covering stainless MIG welding in one of your next videos, Jody? You can't find any valuable information on stainless mig on youtube.

Best regards from Germany,
Phil

[Poland308]

I'm not sure what they run for wire at the shop but I know they use 95/5 for SS MIG.

[Slawkos]

Hi,

as far as I know the wire grade is dependable of the base metal. Regarding to the gas the usual mixes used for mild and carbon steel will live SS welds with a black surface film and lots of spatter, the best for MIGging SS is Stainshield Light and Stainshield Universal (formerly Argoshield 90, Helishield TG and Argoshield 101)
The first is used in the MIG welding of thickness range of 0.5 mm to 3 mm. It is suitable for both manual and automatic applications. Widely used to weld automotive components such as exhaust, sheet metal components like heating and ventilation ducting. Specifically formulated for dip transfer with solid wire, producing minimal spatter. Austenitic, ferritic, martensitic and duplex SS, Nickel alloys (not Monels).
The second (Universal) for heavier SS plate 3mm to 10mm.
You can supply them in Germany with BOC gases.
Good luck

[Rick_H]

Typically use a Tri-mix with stainless mig... 90% helium, 7.5%argon, 2%carbon dioxide

[RST Driver]

Hello guys, thanks for your replies.
Now I am torn between two options. First there is the easily available 82/2 Ar/CO2, second is the virtually nonexistent (at least here in Germany) tri-mix gas with an enormous amout of helium. What we do have here are tri-mix gases with about 30% He, 68% Ar and 2% CO2, which are noticably more expensive than 82/2 Ar/CO2.

On top of that I found this:
http://www.weldreality.com/MIG_welding_gases.htm

Form what I have learned so far helium is especially used on thick Aluminum welding where every bit of extra heat input is welcome. On the other hand helium tends to destabilise the arc. Therefore I doubt tri-mix gases are the perfect solution for my kind of welding (which will be short arc GMAW on 1.0-2.5mm stainless steel)...

Best regards,
Phil

[Rick_H]

I have welded 16g 304L sheet with the trigas with no issues