Hey all, so 10 years ago I got a stainless exhaust that was meant to be tig welded. My joints are rusting way faster than the exhaust. Do you think the guy might have welded it with mild steel wire?
Looking for opinion on 'tig' welded exhaust (1 Viewer)
- Thread starter HarryHarrison
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Malleus
Far west of Siegen
Maybe, but what caused the material failure was poor material. All stainless steel is not created equal. Some isn't even stainless.
Here's a little bit of info on the topic: Ulbrich stainless steel
Here's a little bit of info on the topic: Ulbrich stainless steel
Nardulli
GOLD Star
Stainless comes in many forms. 316 is best for exhaust. 304 or less and right there’s what you get. He almost certainly used a mild steel rod. The weld area will likely corrode faster than the stainless steel base metal because mild steel filler lacks the corrosion-resistant properties of stainless steel. This is especially problematic in environments exposed to moisture, chemicals, or high temperatures.
All accurate info. Has he said a much you could have hit it with galv paint or some other type to keep it from happening. It doesn't look as if it was even 304. Tbh it looks cheap . I didn't look where ya are located but even on the coast it shouldn't have done it that fast
- Thread starter
- #6
Haha wtf clearly you know nothing about vehicles and that generally exhausts are replaced multiple times during the life of the vehicle. I feel like you get surprised by trivial s*** multiple times a day if that's your only input
- Thread starter
- #7
To the three above pissesthebed thanks for your input and information 
EWheeler
GOLD Star
That pipe does not look like it is stainless.....I've never seen stainless corrode like that before. That looks like aluminized steel tubing?
There are TIG fillers that are meant to join stainless to carbon steel, so while it may have been TIG welded, it is possible they may not have used the correct filler?
Also, when you TIG weld stainless, you have to back purge the inside with an inert gas, otherwise you'll get lack of fusion and/or "surgaring" of the weld. Failure to back purge will lead to accelerated corrosion from the inside of the weld. To me it looks like those holes are coming from the inside and eating outwards?
When working with stainless, you have to take care to not contaminate it with iron from carbon steel. Proper practice is to chemically passivate the outside of the weld area after welding to neutralize any free iron and help form the oxidation layer over the weld so it doesn't corrode. Usually the corrosion I have seen is pinhole corrosion/failure due to contamination, not the complete corrosion of large surface areas like what is shown. I don't live in an area where salt is used though, so my experience with stainless & salt exposure is minimal as far as motorsports goes.
I recently did some work in a plant that handles sea water. All of the piping was TIG welded SMO-254, a high grade stainless alloy: Alloy 254 Stainless Steel - Penn Stainless - https://www.pennstainless.com/resources/product-information/stainless-grades/6-moly-grades/alloy-254-stainless-steel/
Part of the welder qualification was an accelerated corrosion test of the weld coupon, and in my research it was shown that these alloys are VERY susceptible to corrosion failure if the heat input during welding is too high due to some changes in molecular structure. The joint could x-ray shoot and pass, but could fail due to corrosion. There have been numerous case studies of welds passing X-ray and then a year later everything starts leaking/failing after being put into service with the cause likely being too much heat input during welding and exponentially accelerated corrosion taking place.
I say all this to help shed light on the fact that just because stainless material is used, even the proper filler, it does not mean it is fool proof corrosion resistant....
There are TIG fillers that are meant to join stainless to carbon steel, so while it may have been TIG welded, it is possible they may not have used the correct filler?
Also, when you TIG weld stainless, you have to back purge the inside with an inert gas, otherwise you'll get lack of fusion and/or "surgaring" of the weld. Failure to back purge will lead to accelerated corrosion from the inside of the weld. To me it looks like those holes are coming from the inside and eating outwards?
When working with stainless, you have to take care to not contaminate it with iron from carbon steel. Proper practice is to chemically passivate the outside of the weld area after welding to neutralize any free iron and help form the oxidation layer over the weld so it doesn't corrode. Usually the corrosion I have seen is pinhole corrosion/failure due to contamination, not the complete corrosion of large surface areas like what is shown. I don't live in an area where salt is used though, so my experience with stainless & salt exposure is minimal as far as motorsports goes.
I recently did some work in a plant that handles sea water. All of the piping was TIG welded SMO-254, a high grade stainless alloy: Alloy 254 Stainless Steel - Penn Stainless - https://www.pennstainless.com/resources/product-information/stainless-grades/6-moly-grades/alloy-254-stainless-steel/
Part of the welder qualification was an accelerated corrosion test of the weld coupon, and in my research it was shown that these alloys are VERY susceptible to corrosion failure if the heat input during welding is too high due to some changes in molecular structure. The joint could x-ray shoot and pass, but could fail due to corrosion. There have been numerous case studies of welds passing X-ray and then a year later everything starts leaking/failing after being put into service with the cause likely being too much heat input during welding and exponentially accelerated corrosion taking place.
I say all this to help shed light on the fact that just because stainless material is used, even the proper filler, it does not mean it is fool proof corrosion resistant....
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- Thread starter
- #10
Thanks 4 out of 5 guys! I love the information you've gone out your way to type and share! What do you think cat back (two aftermarket cats) should have cost me back in 2015? Medium size industrial estate - garage. Located- lower mainland BC. I mean s***, I don't even know if this should be thrown in the trash at this point rather than try repair? It seems that their work has left me with a nightmare! I cannot afford to buy another exhaust. I've slept in my LC for 6 years in March/disabled. I've a spinal injury that goes into my neck and base of my skull. It's going to be a nightmare either way really 
- Thread starter
- #11
I mean here's what it cost me $2100 CAD
- Thread starter
- #12
For what's it's worth to add to the information- kept my Toyota cat/used my original O2 sensors in this build. +Tax.
I know it's been 10 years but I only put on 20,000km in that time.
I know it's been 10 years but I only put on 20,000km in that time.
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EWheeler
GOLD Star
Sorry to hear of your situation. $2100 sounds expensive. Problem is your Province salts the roads. I firmly believe road salting is a scam with the manufacturers to deteriorate vehicles faster than normal conditions would allow. No reason for the lower Mainland to salt roads when Washington state does not. I would try to find a shop with some empathy for your situation that can replace the rotting components at a reasonable cost. No reason aluminized steel with mig welds wont get the job done, at a fraction of the cost of TIG welded aluminum.Thanks 4 out of 5 guys! I love the information you've gone out your way to type and share! What do you think cat back (two aftermarket cats) should have cost me back in 2015? Medium size industrial estate - garage. Located- lower mainland BC. I mean s***, I don't even know if this should be thrown in the trash at this point rather than try repair? It seems that their work has left me with a nightmare! I cannot afford to buy another exhaust. I've slept in my LC for 6 years in March/disabled. I've a spinal injury that goes into my neck and base of my skull. It's going to be a nightmare either way really
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- Thread starter
- #14
Thanks mate. I'm legit that broke that I'm forced to do all the jobs myself or try to. It's gonna take months. I'm stuck to mig welding it and have to be only flux core. Landlord doesn't want gas bottles for welding or cutting. Maybe the shop that made it can take a look, I'll ask
- Thread starter
- #15
I stand corrected, it's 6.5yrs since it was installed!
- Thread starter
- #16
Also, spoke to owner and it's mild steel, mig welded. There's most the problem, I thought that price was stainless. Apparently $5000+ for stainless tig welded.
pb4ugo
SILVER Star
Find a new exhaust guy.
- Thread starter
- #18
Too expensive
Too expensive and s***ty weld?
