SSZ

I bought a stainless muffler for my car. I want to weld it to the downpipe which is mild steel. I have a mig welder, its a Millermatic 252.
WHat is recommended for welding the mild to the stainless? ANy special gas i need or a specific wire?
THanks

Bowtie316

iTrader: (1)

Is it going to be a butt weld or will the downpipe slide inside the muffler?

If it slides inside, I would just weld it with what you have. Probably ER70s-6 and CO2. Most of the strength will be provided by the slip fit, the weld will just seal and keep the joint from rotating.

If it's going to be a butt weld, it would be better to tig it with ER309 and argon.

SSZ

ok thanks. i was planning to do a slip fit

Blown06

iTrader: (32)

I'm with this guy

PEPFAB

iTrader: (1)

agree^ we do this almost on a dayly basis, the best would be to use stainless wire but er70 wire should go for a while before it crack from stress

jlcustomz

For just a slip fit with stainless & non stainless, I'd just mig weld With the standard steel wire & 75/25 gas, the spray paint the weld With galvanizing spray or any high heat paint to slow down the rusting process. 75/25 mix is cleaner, but more costly than plain co2.

If you were to use stainless wire & stainless weld with a mig, you'd need tri-mix gas. I used to use tri-mix for everything since it seems to make a cleaner & hotter weld, but the mix has become pretty pricy due to the helium.

Keep it simple.