Otto, I think I will take that advice and roll with it, ER70S2 it is.

Thanks again everyone for quick responses. It looks like a crisis averted and huge lesson learned.

Thank you for the kind words! So is the consensus that I should have used a more appropriate filler vs what we have laying around? And that this will stay together for me? What if, on my second housing (already tacked, as well as a few full welds with 316L) I used e70s6(2?) on the rest. Is it better...

Thank you all so much for your responses.... Here are a couple pictures. I hope all is not lost!

Bummer! So if I'm reading correctly I should probably scrap this housing? I'd hate to do this but I'd also hate to cut it out of a finished chassis on down the line if it develops problems. Is there any testing I can do on these welds? I think I saw a dye test in another post. Will that be accurate?...

Yes the pieces are mild steel. They are laser cut.

Also I am using 316L will this have any difference to the 309L?

I am building two mini buggies. (Single seat, long trav suspension, sport bike motors). There is a rear end housing that has mounts for double A Arm suspension and there is a center section containing the sprocket brake and axles. I have access to a TIG Machine and bottomless SS rod. I have welded t...