Poland308 wrote:Could be a real bad quality casting with lots of porosity internally, before you even light up on it. Or it might be saturated with oil residue from the exhaust. If it’s oil contamination then the preheat should help some.

This makes sense!

I did preheat to 500 + deg. I have nickle rod, I have silicon bronze filler, I tried to mig it just to see. Every process acts like I'm wire welding without any gas. The nickle rod just balls up, some spots it will just knock off with chipping hammer. I have welded cast iron, many times. had a guy c...

I am trying to weld up an exhaust manifold off of a Bobcat. I have cleaned it and grooved it, I have tried to arc with nickle rod, TIG it and just straight Mig it. Every process acts like Im welding steel with the gas turned off. I have welded a cast manifold completely back together before. But thi...