Stainless Welding

[ItsNemo]

Ok, on the cheap here, need to do a small repair on 304 stainless exhaust where there's a cracked weld between the pipe and the cat. Have a Miller Multimatic 215, only setup for MIG/Stick (no TIG kit) and tank of C25, have only experience MIG welding. Don't really feel like buying a tank of tri-mix or buying the TIG kit.

What options do I have? Flux core? Learn stick and get right electrode? Stainless wire with C25 anyway?

 

[chickenfarmer]

If cheap is all that matters, just pretend its steel and weld it like steel with c25 and regular wire. It mig welds virtually the same, the only difference will be that the weld joint will rust.
Why did you buy the 215 if your not willing to get the tig kit?

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[Bodj Built]

Take it to an auto/offroad shop that can TIG it. If you can take it off the vehicle, clean it with a scotchbrite pad and acetone, and possibly clean the inside, it should only take them a minute or two and maybe $20 or $30... Not worth the headache of doing it wrong if you're not going to buy the correct tooling.

 

[Farmall450]

If cheap is all that matters, just pretend its steel and weld it like steel with c25 and regular wire. It mig welds virtually the same, the only difference will be that the weld joint will rust.
Why did you buy the 215 if your not willing to get the tig kit?

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This. It's been done before. Welded like ****, in my experience, but it's been done.

 

[Lwel9226]

I have done this with stainless wire and straight argon.... Lots cheaper than tri mix...

LynnW

 

[danski0224]

Silicon bronze wire and argon.

 

[dogdog]

Pay some one ? If you are not looking for show room quality..... you can just straight mig it... it'll stick, the joint might rust a bit but will be fine. Mine have been holding fine for past .... since 2011...

 

[joe_padavano]

Pay some one ? If you are not looking for show room quality..... you can just straight mig it... it'll stick, the joint might rust a bit but will be fine. Mine have been holding fine for past .... since 2011...

^^^THIS. I've gas welded stainless using mild steel filler. Not pretty but good enough for an exhaust system.

 

[ItsNemo]

If cheap is all that matters, just pretend its steel and weld it like steel with c25 and regular wire. It mig welds virtually the same, the only difference will be that the weld joint will rust.
Why did you buy the 215 if your not willing to get the tig kit?

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Willing? Sure, wanting to spend $1000 right now (Canada, our prices are higher) on a second tank for argon and the tig kit? Not so much.

And I also don't know what world you guys live in where there's a local shop that won't charge $100 minimum for any work, no matter how quick/simple it would be.

In any case, looks/rust don't terribly matter...so will probably just have at it. Better to use stainless wire or just regular mild steel wire with it? I also assume that mig with the wrong setup is better than stick with stainless rods?

 

[danski0224]

And I also don't know what world you guys live in where there's a local shop that won't charge $100 minimum for any work, no matter how quick/simple it would be.

That world is Garage Journal Dreamland.

 

[MoonRise]

Best way - TIG with 308 (or 309 or 316) filler wire and back purge

Next best - GMAW with tri-mix and stainless 308 wire (or 309 or 316)

Next next best - GMAW with stainless 308 wire (or 309 or 316) and C25, single pass weld only and you shouldn't get too much carbon pick-up from the shielding gas.

Not really an option unless you are an SMAW god at welding thin wall tube - 3/32" 308/308L-16 or -17 rod at the lowest amps it will run (40-50 amps usually), or 1/16" similar rod at 30-40 amps.

No FCAW, even if you wanted to get a $$$ spool of stainless FCAW-S wire.

Plain ER70 carbon steel wire and C25 will weld the stainless, at least initially, but it WILL rust. Rather quickly, especially due to hot exhaust and road salt and dissimilar metals.

A 2 pound spool of stainless wire (name brand stuff) is probably going to run you about $35 all by itself. No-name or 'off' brand might be about $20. That's US dollars, so in Canadian that's probably about $500CAN .

3/32" stainless stick is about $10/lb, but you usually have to buy an 8-10 pound can, 1/16" stick is about $14/lb, and again you usually have to buy an 8-10 lb can.

 

[Bigblue&Goldie]

And I also don't know what world you guys live in where there's a local shop that won't charge $100 minimum for any work, no matter how quick/simple it would be.

I think you'd be surprised. Before I owned a tubing bender I walked into Campbell Enterprises and asked if they could make a single bend in a piece of 1" DOM tubing. Not only did they GIVE me the piece of tube, but they bent it for free also. We fully expected to pay shop rate the whole way.

A simple tig weld takes a guy a few minutes to get setup and burn in, especially if you aren't concerned about purging the tubing. Another option is hit up a local board member. I know I'd try my best to help a local board member with such a simple task.

 

[ItsNemo]

Best way - TIG with 308 (or 309 or 316) filler wire and back purge

Next best - GMAW with tri-mix and stainless 308 wire (or 309 or 316)

Next next best - GMAW with stainless 308 wire (or 309 or 316) and C25, single pass weld only and you shouldn't get too much carbon pick-up from the shielding gas.

Not really an option unless you are an SMAW god at welding thin wall tube - 3/32" 308/308L-16 or -17 rod at the lowest amps it will run (40-50 amps usually), or 1/16" similar rod at 30-40 amps.

No FCAW, even if you wanted to get a $$$ spool of stainless FCAW-S wire.

Plain ER70 carbon steel wire and C25 will weld the stainless, at least initially, but it WILL rust. Rather quickly, especially due to hot exhaust and road salt and dissimilar metals.

A 2 pound spool of stainless wire (name brand stuff) is probably going to run you about $35 all by itself. No-name or 'off' brand might be about $20. That's US dollars, so in Canadian that's probably about $500CAN .

3/32" stainless stick is about $10/lb, but you usually have to buy an 8-10 pound can, 1/16" stick is about $14/lb, and again you usually have to buy an 8-10 lb can.

This was super helpful.

A 2lb roll of hobart stainless mig wire is $45 here, powerweld brand I can get for $35...sounds like the way to go.

 

[Mr. T]

Take this with a grain of salt since I’m neither a good or terribly experienced welder. But in this application if you don’t use the correct gas and a back purge I think you’re going to get a brittle weld that won’t last.

 

[rtz]

Get a roll of flux stainless:

Blue Demon 308LFC-O X .035 X 1# Spool stainless steel flux cored gasless welding wire https://www.amazon.com/dp/B00G5GHA7E/?tag=atomicindus08-20

 

[Bodj Built]

I think you'd be surprised. Before I owned a tubing bender I walked into Campbell Enterprises and asked if they could make a single bend in a piece of 1" DOM tubing. Not only did they GIVE me the piece of tube, but they bent it for free also. We fully expected to pay shop rate the whole way.

A simple tig weld takes a guy a few minutes to get setup and burn in, especially if you aren't concerned about purging the tubing. Another option is hit up a local board member. I know I'd try my best to help a local board member with such a simple task.

Bingo. I do quick jobs for people all the time. If it's a 3 or 4 minute thing and they pay me $15, that's $10 for lunch today and $5 towards tomorrow's lunch. If I have to take out multiple tools, grind, remove parts... then I charge full pop.

 

[Lwel9226]

Get a roll of flux stainless:

Blue Demon 308LFC-O X .035 X 1# Spool stainless steel flux cored gasless welding wire https://www.amazon.com/dp/B00G5GHA7E/?tag=atomicindus08-20

That will probably burn much much too hot for exhaust tube.....

LW

 

[sberry]

Just weld it with the mig, welds like stainless and will rust a little. It welds well.

 

[ItsNemo]

For the record, did the welding yesterday with stainless wire and C25 regardless...went ok, stuck the metal together...welds weren't super pretty, puddle didn't wet very well (as would be expected without trimix) and turning up the heat was getting it close to blowing through, so they were a bit ropy, but solid enough for the purpose.

No pics lol

 

[welder4956]

For the record, did the welding yesterday with stainless wire and C25 regardless...went ok, stuck the metal together...welds weren't super pretty, puddle didn't wet very well (as would be expected without trimix) and turning up the heat was getting it close to blowing through, so they were a bit ropy, but solid enough for the purpose.

No pics lol

Glad to hear it went OK. C25 is not the optimum gas for stainless mig, but it will be fine for an exhaust pipe repair.

 

[fordkid88]

Gold gas mix. Super expensive. Mostly helium. Good luck getting it.