Hot Rods best way to weld stainless exhaust

best way to weld stainless exhaust tig? or mig ? i will probally have to try mig as my tig skills may not be up to it

 

Tig. With stainless rod. Why use stainless only to weld it with steel wire from a Mig that will rust?

 

308 stainless wire for Mig will work. Purge the inside with Argon for a better result.

 

And I would think you need pure argon for Mig? Practice a little with Tig, SS is much easier to weld then steel.

 

You need Tri-Mix as the shielding gas to Mig, and argon as a purge gas inside the pipe to get the best results with 308L wire. A small bottle of Tri-Mix will give you about 4 hours of welding. Tig needs pure argon for both. If you have Tig, practice some and go for it. SS is easier than steel.

 

Ive done lots of welding with MiG on SS with 75/25.

 

I was guessing, know someone would know. I have Tigged SS. I know it can be done but have never seen it Migged.

 

Probably because it will show a rust line where welded.

 

I first saw it done with Mig 30 years ago while building a Dairy Facility for SDSU. It was new to the crew that was doing the SS. It does weld nice

 

I used stainless wire to mig my exhaust 10 years ago not as pretty as tig, but the car is low and you can’t see it any how. 10 years and no rust on the welds.

 

Stick weld with reverse polarity. Been there done it that way and is still on a Lincoln exhaust system since 2002.

 

I also MIG - 308L wire and I switch to my straight Argon bottle. It does a very good job and cleans up pretty. I have some that have been done for years, no rust.
.024 wire/setting 2/speed 60 if you happen to have a Hobart Handler...

 

If you don't want to purge, but want to minimize the weld run through, use Solar Flux. You mix it with alcohol, into a paste, and smear it inside the weld joint. I would use a Tig, if you can, and fit the joints tight.

 

A roll of Stainless mig wire should be easy enough to find. For a one time short time spand deal you can probably rent the bottle for the correct mix and get by with a short term rental cost.
Tig would be nicer if you have access to the welder but not everyone has access and so be it.

We have so many food processing plants here along with wineries and who know how many large dairy farms that finding the stuff to weld stainless isn't an issue.

 

For what it's worth, a gajillion mig welds are done every day on stainless exhaust systems in the auto industry, and none of them are purged.