Welding Stainless Muffler

[rockcrawler]

I ordered a stainless muffler for my Jeep, and when it arrived, I noticed one of the flange studs had popped off and was laying loose in the box. I do not want to go through the trouble of sending it back and ordering another. I just need to spot weld the stud back in place. I have a Hobart Handler 140 Mig welder using 75/25 Argon/CO and .030 solid wire. I’m extremely novice when it comes to welding and just kind of tinker occasionally until I can get into a class of some sort. Can I simply spot weld the bolt, or is there some special process for stainless? Any suggestions on settings?

 

[Danny]

You can weld it with the set up you described it’s just going to rust where you weld it and the area around the weld that will become contaminated.

 

[Colin Len]

^Agreed. And, it's not worth the $$ to upgrade your wire and gas in order to weld SS properly with your MIG. Plus, welding SS isn't super easy compared to what you're used to. AND, the correct way is with TIG anyway.

If you're picky, find a local shop to TIG it for you. Or get a replacement from the company you ordered from. If you're not picky, weld it with your current setup and throw a little paint or coating on there to keep the rust somewhat at bay.

You could also consider replacing the studs with bolts if the setup allows for it.

 

[Rst277]

I ordered a stainless muffler for my Jeep, and when it arrived, I noticed one of the flange studs had popped off and was laying loose in the box. I do not want to go through the trouble of sending it back and ordering another. I just need to spot weld the stud back in place. I have a Hobart Handler 140 Mig welder using 75/25 Argon/CO and .030 solid wire. I’m extremely novice when it comes to welding and just kind of tinker occasionally until I can get into a class of some sort. Can I simply spot weld the bolt, or is there some special process for stainless? Any suggestions on settings?

Return it. The only way you will be happy.

 

[DGersic]

You shouldn’t, but you can get a spool of stainless wire and weld it with that. You're supposed to change the shielding gas, but it will work with what you have.

 

[no704]

To properly mig stainless you need to run straight Argon, SS wire, and reverse polarity. In your situation I’d just use a nut, bolt, and a couple washers.

 

[rockcrawler]

^Agreed. And, it's not worth the $$ to upgrade your wire and gas in order to weld SS properly with your MIG. Plus, welding SS isn't super easy compared to what you're used to. AND, the correct way is with TIG anyway.

If you're picky, find a local shop to TIG it for you. Or get a replacement from the company you ordered from. If you're not picky, weld it with your current setup and throw a little paint or coating on there to keep the rust somewhat at bay.

You could also consider replacing the studs with bolts if the setup allows for it.

I guess a stainless nut, bolt and washers would work.

 

[MoonRise]

To properly mig stainless you need to run straight Argon, SS wire, and reverse polarity. In your situation I’d just use a nut, bolt, and a couple washers.

Nope.

The only typical metal you MIG weld with straight 100% argon is aluminum. All steel MIG welding is done with some amount of active gas in the gas mix, whether that active gas is O2 or CO2.

Short-circuit transfer mode GMAW (aka MIG) on stainless steel is typically done with tri-mix or 98-2 argon-O2. Spray mode GMAW on stainless is typically done with 98-2 argon-O2.

GMAW polarity on stainless steel is the same as on plain steel, DCEP, DC electrode (wire) positive. Work clamp (aka 'ground') is the negative.

To weld stainless steel and keep it (mostly) stainless, you need the proper filler wire and the proper shielding gas and the proper procedures.

Yes you could sort-of weld two pieces of stainless steel together (maybe) with a HH-140 with C25 gas and plain steel filler wire (ER70S-6). The "maybe" is if the HH140 has enough amperage on 120V input power to properly melt the flange AND the broken-off stud back together. And the fact that using C25 gas and mild steel filler wire means that the weld is no longer stainless. And you might get enough carbon pick-up from the C25 in combination with the ER70 wire to possibly get a hardenable witches-brew of an alloy mix in the weld puddle that is hard and brittle.

To the OP, hassle or not just send it back and have them send you a non-broken exhaust. Or drill it out and replace the stud with a stainless steel bolt and nut.

 

[Slednut]

Buy yourself a TIG.

 

[Sumboodie]

Most "stainless" exhaust welds fine with normal mig setup.

 

[andyvh1959]

I modified the interior of the s/s muffler for my 94 BMW R1100RS, made my own baffle system out of stainless, cut the can off at the main huge elbow 0over 4"diameter), MIG tacked the components in place without the outer can on it. Took it to a pro and he TIG welded the whole thing back together. I got it home and polished the outer surfaces he TIG'd. Can't tell it's not OEM, been that way since 2007 with no fails.

 

[slowtwitch73]

I just did this for the first time a few weeks ago.. stainless muffler to regular pipe. Used my standard setup and it worked just fine.. easy.

 

[Jswain]

I guess a stainless nut, bolt and washers would work.

There's the winning ticket. Couple dollars and done..

It's a jeep not a Bugatti. Spot welding the stud on would also be more then fine. Nice thing about bolts is if you need to remove them in the future and they are stuck you just cut them in half. If you use stainless bolts don't impact/power tool them together or they will likely gall the threads & remain together, forever

Sure it should come ready to go, but the hassle of sending it back and waiting for a new one or 5 mins in a hardware store and the jobs done today. Is the juice worth the squeeze.

 

[rockcrawler]

Got‘er done! Just went the bolt and nut route. The weld on the upper cats broke, and when I removed them, a lot of white powder poured out. So, cats were toast. Just went ahead and replaced everything.

 

[Lanzg]

Which Cat System is that? I got the Flow Master when it went on sale, just waiting for some time to mess with it.
LG

 

[rockcrawler]

Which Cat System is that? I got the Flow Master when it went on sale, just waiting for some time to mess with it.
LG

Magnaflow Stainless 2.5”. I have an Nth Degree belly pan so I have to make some bends to the rear cat hanger bar to get it up high to clear the pan. I hate dealing with that thing. It weighs a ton, but it does its job well. I replaced all four oxygen sensors as well. Check engine light is finally off……….for now. It’s been on the last 5 plus years due to multiple issues. Oh well, it’s a Jeep. Pretty sure it’s operating properly if the light is always on.

 

[Lanzg]

Magnaflow Stainless 2.5”. I have an Nth Degree belly pan so I have to make some bends to the rear cat hanger bar to get it up high to clear the pan. I hate dealing with that thing. It weighs a ton, but it does its job well. I replaced all four oxygen sensors as well. Check engine light is finally off……….for now. It’s been on the last 5 plus years due to multiple issues. Oh well, it’s a Jeep. Pretty sure it’s operating properly if the light is always on.

Hahaha correct, I fix/modify them for a living, we ask the customers if they want some or all the lights turned off. Cat efficiency codes and O2s have gotten alot of TJ/LJs sold prematurely. There are ways around it but people get tired of throwing the parts cannon at them and the manifold collector can be a real pain, no one likes to do that twice. If you ever need anything Tigged I'm in NRH and have 5 killers out back that can handle anything, give me a shout.

Which O2's did you use?

LG

 

[rockcrawler]

Hahaha correct, I fix/modify them for a living, we ask the customers if they want some or all the lights turned off. Cat efficiency codes and O2s have gotten alot of TJ/LJs sold prematurely. There are ways around it but people get tired of throwing the parts cannon at them and the manifold collector can be a real pain, no one likes to do that twice. If you ever need anything Tigged I'm in NRH and have 5 killers out back that can handle anything, give me a shout.tK

Which O2's did you use?

LG

Thanks. I was actually going to get the cat weld crack redone. I had one of them fixed a couple of years ago by a guy at a performance shop nearby. But, when I removed it and all that **** poured out, it wasn’t worth it. This dang Jeep has had crazy issues for years. I had the oil pump/camshaft code for a long time. Tried everything I could find on the internet, but nothing fixed it for long. Finally broke down and pulled the motor and replaced the cam, oil pump assembly, sensor, and pretty much all top end parts. Also had to get a PCM from Wranglerfix LLC. Code was finally gone. Now I live in a county that doesn’t care about the check engine light and Texas is about to drop vehicle inspections. So, the check engine light doesn’t worry me anymore.
I only use NGK/NTK oxygen sensors.

 

[ChefRex]

Braze it.