EXHAUST system METALURGY (want to weld to it)

[pk2]

Hello,

I want to wire in another pre-cat O2 sensor (wide band) for tuning. The Pipe is in such good condition I am wondering if it's something exotic...(stainless). Can I weld a new bung to it with a traditional weld or braze or, will require some exotic weld.

Regard, PK

Edited September 13, 2010 by pk2

[therock88]

Hello,

I want to wire in another pre-cat O2 sensor (wide band) for tuning. The Pipe is in such good condition I am wondering if it's something exotic...(stainless). Can I weld a new bung to it with a traditional weld or braze or, will require some exotic weld.

Regard, PK

My understanding is that most, if not all, later model Porsche exhaust components are made of stainless steel as you suspect. I am no metallurgist nor do I know much about welding, but I would think you would need to weld a stainless bead, or you would get rust and or bi-metal corrosion.

I am sure someone on this site will know more about it than I do, but I would not risk a regular weld on a stainless steel component.

Good luck!

DC

[pk2]

Thanks for the reply,

Ya, stainless requires equipment I don't have. On the other hand my cars a 99 so not exactly a late model. I'm being lazy I guess though, I could just stick a magnet on it...but It still could be some weird alloy.

Regards, PK

[therock88]

Thanks for the reply,

Ya, stainless requires equipment I don't have. On the other hand my cars a 99 so not exactly a late model. I'm being lazy I guess though, I could just stick a magnet on it...but It still could be some weird alloy.

Regards, PK

99 would still be stainless.

DC

[tombrand]

It needs to be TIG welded with 308 rod.

Tom Brand

2003 Boxster S

[pk2]

99 would still be stainless.

DC

Great, Thanks.

Time to buddy up to my old neighbor with his plasma torch.

Regards, PK

Edited September 15, 2010 by pk2

[da888]

There's many grades of SS.

308 is an all around rod to use but Inconel might be a better choice.(there are different grades and sizes of this to, so ask someone's who knows for sure, 1/16 " or smaller) It's more of a blend and is softer. Used to make transition welds and when the material is not known.

After that you have to consider cracking. SS is picky at times, especially casted material. I would preheat the base metal and have it bolted in place or to a fixture to make sure it doesn't warp. SS can really, really warp.

Make sure the bead is not concave, that's a crack starter for sure.

I've been a turbine welder for a long time in powerplants so I know what I'm talking about. Good luck.

[pk2]

There's many grades of SS.

308 is an all around rod to use but Inconel might be a better choice.(there are different grades and sizes of this to, so ask someone's who knows for sure, 1/16 " or smaller) It's more of a blend and is softer. Used to make transition welds and when the material is not known.

After that you have to consider cracking. SS is picky at times, especially casted material. I would preheat the base metal and have it bolted in place or to a fixture to make sure it doesn't warp. SS can really, really warp.

Make sure the bead is not concave, that's a crack starter for sure.

I've been a turbine welder for a long time in powerplants so I know what I'm talking about. Good luck.

Thanks, I forgot about the different s.s. variants. I got a stainless bung and who know what it is. I'll convey your thoughts to my friend the welder.

PK