Stainless MIG welding gas

[duncancento]

I've had a bit of practice MIG welding mild steel exhausts but I'm now making a stainless system.

I've got a roll of stainless wire but I'm puzzled on what gas to use, I think I'm right in saying I'll need Argon/CO2 mix but will a 80/20 mix be ok?

I'm looking at something like this:

weldingsuperstore.co.uk/mig-welding/welding-gases-regulators/disposable-cylinders/argon-co2-disposable-gas-bottle-single-598.html

There is a BOC round the corner from my work but I don't really want a massive bottle with rent, I'm only planning on doing this one exhaust.

Any advice appreciated!

[bobblegut]

don't use co2 mix , it will make tour weld porous and brittle . You need pure argon . If your going to be welding other stuff i would get a no rental bottle of argon . don't bother with disposables , 100 times more expensive .

[smurf]

+1 for pure argon

If you want it super clean inside the exhaust you can back purge as well but definitely pure argon only

[docjohn]

Jul 30, 2014 8:15:23 GMT smurf said:

+1 for pure argon

If you want it super clean inside the exhaust you can back purge as well but definitely pure argon only

Yes, definitely go for rent-free pure argon. As well as back purging I use Solarflux; other stainless steel welding back up fluxes are available.