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Old 09-18-2019, 02:31 PM   #1
segerton
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Default Mig vs Tig for T304 cobb exhaust

So I'm getting one of those Ultra Quiet Resonators for my Cobb exhaust system to get rid of some drone. Both are 304 stainless.

My exhaust shop says they use MIG. Should I look for another shop that does TIG?
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Old 09-18-2019, 11:52 PM   #2
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Quote:
Originally Posted by segerton View Post
So I'm getting one of those Ultra Quiet Resonators for my Cobb exhaust system to get rid of some drone. Both are 304 stainless.

My exhaust shop says they use MIG. Should I look for another shop that does TIG?
Yes.

You can do mig well on stainless, but it's annoying and takes special (expensive) gas to do right, which a lot of places don't actually do. Which eventually results in a rusty mess. And if they do use the right gas the odds are high that they won't be purging with fancy gas and you'll eventually end up with a rusty weld. Paying someone to do tig on stainless really shouldn't cost more then paying someone to do mig correctly on stainless.
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Old 09-19-2019, 03:14 PM   #3
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Thanks for the advice. Last thing I want is some rusty stainless..
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Old 09-19-2019, 03:36 PM   #4
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I would mark where you want them to go and take the mid pipe off. Take it to a welding shop and have them Tig it. if they ask you if you want it back purged, I wouldn't bother for that part of the exhaust.
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Old 09-19-2019, 04:03 PM   #5
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I can't believe anyone would even want to mig stainless that thin. That would be a nightmare.
Migging stainless sucks
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Old 09-19-2019, 08:02 PM   #6
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Starting to think I might just get some 3" band clamp and DIY it. Bad idea?



https://www.amazon.com/TOTALFLOW-TF-...ay&sr=8-1&th=1
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Old 09-19-2019, 11:10 PM   #7
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Quote:
Originally Posted by segerton View Post
Starting to think I might just get some 3" band clamp and DIY it. Bad idea?
I'd call that less bad than MIG with the wrong gas, you might have a little leak from time to time and you might need to figure out an additional hanger, but I'd take that over rust.

This is the actual correct answer:
Quote:
Originally Posted by JSR84 View Post
I would mark where you want them to go and take the mid pipe off. Take it to a welding shop and have them Tig it.
Measure twice (or more) and mark it well. It will probably cost less than you expect and should last.
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Old 09-19-2019, 11:23 PM   #8
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Originally Posted by rtv900 View Post
I can't believe anyone would even want to mig stainless that thin. That would be a nightmare.
Migging stainless sucks
I've done it twice on custom downpipes and would never wish it on anyone. Once with the wrong gas (rusted through in one Chicago winter) then once with fancy tri mix gas (still in service with no issues 4 years later). Both times were a pain in the butt. Never again.
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Old 09-20-2019, 06:45 AM   #9
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Thanks for the advice. Are there any heat resistant blanket wrap products that would help with drone? I’ve seen pipe heat/insulation wraps in industrial applications with zippers that would fit.
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Old 10-13-2019, 05:50 PM   #10
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Mig welding stainless is ok if they are using stainless wire and argon, technically it should be purged too, but doubtful any shop with just a mig would do that.

A lot of shops will just use mild steel wire and (gas argon/co2) mix to weld on stainless exhausts, this you really want to avoid since it will rust easily.
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Old 10-14-2019, 12:20 PM   #11
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Quote:
Originally Posted by notaduc View Post
Mig welding stainless is ok if they are using stainless wire and argon, technically it should be purged too, but doubtful any shop with just a mig would do that.

A lot of shops will just use mild steel wire and (gas argon/co2) mix to weld on stainless exhausts, this you really want to avoid since it will rust easily.
using plain steel wire to weld stainless would be the worst hack job ever and anybody who would do that should be ashamed of themselves.
plus, migging stainless can have oxygen in the mix believe it or not
straight argon is for tig
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Old 02-05-2020, 10:37 PM   #12
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I've done what you want to have done.

It can be done with MIG (75Argon/25CO2). I used .024 304 wire in a Miller Multimatic and it came out fine, just ugly. Back purge optional. The only reason I did MIG was because the customer was trying to save money for whatever reason, he probably sold the car right after.

I recommend TIG with pure argon and 304 filler. The weld comes out nicer and you have more control for thinner material. It takes longer and you end up paying for that. Back purging is optional for anything that doesn't see pressure or excessive heat. A Catalytic converter should be back purged, a down pipe should be back purged, a header should be back purged, a muffler does not have to be back purged but it's recommended for a strong weld.
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Old 02-21-2020, 03:23 PM   #13
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I did the exact same thing on my Cobb mid pipe, I did Tig weld it and its worked great. Just make sure you keep all the parts in the same plane when you cut it.
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Old 02-21-2020, 07:22 PM   #14
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Quote:
Originally Posted by Token-Negro View Post
I did the exact same thing on my Cobb mid pipe, I did Tig weld it and its worked great. Just make sure you keep all the parts in the same plane when you cut it.


Did it help the drone much?
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