welding stainless with flux core wire

[zze86]

It's recommended to backpurge when welding stainless with gas to limit impurities from contaminating the weld. If using a flux core wire should you also backpurge?

 

[G-ManBart]

It really depend on what you're welding. In many cases back purging is really not necessary.

 

[steel 35]

I agree, & guess your not building a brewery already, because you can’t polish that out.

 

[zze86]

At the moment, I was looking at fabricating a custom header and y-pipe. No good aftermarket alternatives available. I was thinking of mocking one up and tack welding it, then take it to a real welder to finish up but further down the line probably a full exhaust. Maybe for other vehicles as well if it can make solid joins.

 

[steel 35]

No.

 

[steel 35]

stick Weld?
or stainless filler wire.
stainless mig wire is available

I have done several large stainless exhaust mig steel wire, No purge

 

[Walkers]

Purge is really only if you are using a gas type of welding process.

 

[steel 35]

Purge is really only if you are using a gas type of welding process.

No

 

[Walkers]

No

Well, unless you think you are going to do sanitary tube welding with a flux core machine then, yes. I know it is not the be all, end all answer, but for the OP it is. It sounds more like he wants some SS stuff to stick together, not necessarily do SubArc on nuclear power plant systems.

 

[zze86]

stick Weld?
or stainless filler wire.
stainless mig wire is available

I have done several large stainless exhaust mig steel wire, No purge

I was going to use this Blue Demon stuff. I know you can just use regular ole steel wire but base metal will be SS for that bling factor so may as well use the SS wire.

 

[zze86]

Well, unless you think you are going to do sanitary tube welding with a flux core machine then, yes. I know it is not the be all, end all answer, but for the OP it is. It sounds more like he wants some SS stuff to stick together, not necessarily do SubArc on nuclear power plant systems.

Right on. Definitely won't be doing anything super critical but I'd also like to not have to take an exhaust off and fix cracks later on.

 

[Walkers]

Right on. Definitely won't be doing anything super critical but I'd also like to not have to take an exhaust off and fix cracks later on.

If you are welding exhaust, it is probably more important to make sure you are using the right alloy for welding. The 409 tubing is pretty forgiving though.

 

[speed bump]

There isn't a lot of FCAW wire for stainless, we use it for welding in our kiln but I can't remember what type it is. Most of what is available is either an FCAW gas or GMAW wire. For tacks a backpurge isn't necessary, I would also argue for exhaust it isn't necessary but some people hate seeing the sugaring on the backside though.

 

[steel 35]

I have done several large stainless exhaust mig steel wire, No purge

I did these exhaust's out of scraps, to practice fitting the pieces,
The only one that broke was a under drive shaft cross loop that I put in a Nova of mine.
Had one come in my lane!
Sold it to a friend and he broke it?
Might have had something to do with hand controls
I did it for a few years for two companies.