Can I weld stainless (exhaust) with a MIG 175 w/ flux?
02-22-2004, 12:04 PM
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Can I weld stainless (exhaust) with a MIG 175 w/ flux? I'm thinking about picking up a MIG 175 that comes with flux coil... Will I be able to do some stainless welding for some exhaust components? I'm really not concerned with the appearance of the weld and I'm not going to deal with buying gas/gas conversion at this point.
TIA.
TIA.
02-22-2004, 02:56 PM
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I tried it and it turned out like ****. Couldn't help from burning through. Ended up with a gorilla weld that did seal though. Comes out very nice though with the argon/co2.
02-22-2004, 06:11 PM
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It took some practice, but I can make clean welds on stainless with flux-core mild steel wire. A word of warning though, the weld is very brittle and will crack over time 
02-23-2004, 05:13 PM
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I am not sure with a mig as I dont use one very often, But with a stick welder which I am quite familiar with you have to use different rod like a nickle alloy or the weld will just crack and fall off so you will probably need different wire in your mig for this. I woud check at a weld shop they could tell you exactly what wire you need.
Last edited by tamanjld; 02-23-2004 at 05:39 PM.
02-23-2004, 06:33 PM
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Do any of you guys happen to know if the average decent-sized exhaust shop would have the proper welder/materials/etc. to weld the soft stainless used on most of these high dollar LS1 Y-pipes & catbacks (T-304 I guess it is?)?
02-25-2004, 08:03 AM
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Cars have been stainless, at least cat forward, since
the EPA mandated a 5-year (?) emissions warranty.
So shops have had plenty of time and reason to be
able to weld stainless. But, they also will use the
cheapest they can get away with. I'd ask them if
they use stainless wire or not, case by case.
I don't know if you can get stainless flux-cored wire
or not. If so, you want the thinnest you can get so
as to have less penetration. Mild steel wire snarfs up
the stainless steel's other constituents and makes
the metal in the weld unlike either native SS or the
filler. Also you want to scuff off any thick oxide on
the surface before weld, SS protects with a CrO2
native oxide layer. For a penetrating weld you can
bet you blew this away but on exhaust you're trying
to get by with minimal penetration, a surface bead.
I'd check first and be sure you can find a thin SS
cored wire (in a size that your pinch roller can make
traction on). If so, take the chance, practice on
scrap and you should do OK.
the EPA mandated a 5-year (?) emissions warranty.
So shops have had plenty of time and reason to be
able to weld stainless. But, they also will use the
cheapest they can get away with. I'd ask them if
they use stainless wire or not, case by case.
I don't know if you can get stainless flux-cored wire
or not. If so, you want the thinnest you can get so
as to have less penetration. Mild steel wire snarfs up
the stainless steel's other constituents and makes
the metal in the weld unlike either native SS or the
filler. Also you want to scuff off any thick oxide on
the surface before weld, SS protects with a CrO2
native oxide layer. For a penetrating weld you can
bet you blew this away but on exhaust you're trying
to get by with minimal penetration, a surface bead.
I'd check first and be sure you can find a thin SS
cored wire (in a size that your pinch roller can make
traction on). If so, take the chance, practice on
scrap and you should do OK.
03-17-2004, 09:51 PM
#7
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Just an FYI - this past week I welded up two downpipe-catalytic converter setups w/ the flux core MIG setup I have. The weld turned out great - good penetration, great strength - complete seal. A little bit of spatter, but who gives a F. 
BTW - the cat was stainless and the downpipe was mild steel.
BTW - the cat was stainless and the downpipe was mild steel.
