Welding SS 409 flanges on catalytic converter w/flux core SS E308LFC-O 030 wire

[ajaxthedog89]

I have to weld some stainless grade 409 flanges on a catalytic converter because some slime ball stole my cat. I measured the steel and it looks like close to 15 gauge, 1.75mm thick. I bought some flux core stainless E308LFC-O 030 wire because buying a whole gas tank for just this small project was cost prohibitive. I normally weld mild steel sheet metal around 19 gauge with ER70 wire using the Argon/CO2 gas mix which I read isn't the right stuff for this. Flux core wire seemed like a logical solution.

My question is, can you recommend starting values on my Millermatic 211 MIG Welder w/Advanced Auto Set 907614? I'm guessing 220V DCEP based on Amazon reviews, but beyond that don't know. Nothing on the Miller app or door for this situation, and they have been less than helpful via email contact. I know I have to experiment/practice, but looking for head start advice. Thanks.

[ryanjones2150]

Start around 19-20v and 120ipm and work up from there. That’ll probably be on the cold side to start, but welding thick to thin, you’ll definitely want to make a few practice runs first. Are you doing this on the vehicle or can you get it on the bench?

I hate a thief.

[ajaxthedog89]

Thanks for the advice, something to start with. Yeah, cat converter stolen in an RTD train parking lot! You'd think the city would have cameras and want to catch these people but the cops really don't seem to care. In Colorado replacement cat has to be CARB approved which makes for $$$ cost. The same replacement cat without flanges runs $500, about $600 less than one with flanges. So all told I'm out about $600 plus my troubles. Would have been way higher if I had a shop do the work, so I feel for people in that situation.

It's on the bench.

[ajaxthedog89]

Well it didn't come out great but it was passable for an exhaust system on an old car The settings I used are in the photo. The metal was doubled up 15 gauge against a 1/4" flange plate. Took it through emissions and passed with flying colors, yay!

So for the SS flux core wire I'd say it's OK in a pinch but not if you are looking for top quality welds. That said I'm not the best welder, just a hobbyist, so maybe you can do better. The economics of buying a gas bottle vs. a pound of this stuff definitely make it worth trying. And of course, practice, practice, practice...

[ryanjones2150]

Any idea on what the actual WFS and voltage was?

What’s an RTD parking lot?

[MAC702]

RTD is the Regional Transportation District for Denver's public transportation system.

[ryanjones2150]

Seems like a popular place for thieves. Down here they like pretty much any parking lot where people leave their cars to take a bus or other bulk transport in. There are several lots here where the industry workers park during the expansion projects, it’s also popular spot for bad guys. I guess they’re easy targets since the arrival and departure of people is predictable.