Exhaust Manifold Repaired

[kvwall]

After days of study and reading forums, I took a stab at welding a cast iron exhaust manifold. I think it came out pretty nice so I just wanted to share.

It was a modification, not a repair. I had to cut the flange off and rotate it to make more room under the hood. Here's the procedure I used:

Cut flange and thoroughly cleaned and beveled the area to be welded.
Placed manifold in the oven to preheat. Got it to 380 degrees.
Tig welded on AC with 3/32 thoriated tungsten at 175 amps.
Used Ni-99 filler.
Completed root pass and placed back in the oven for 30 minutes so it wouldn't cool too fast.
Completed another pass and placed in oven to cool for 4 hours. Oven off.
Done.

I hope it holds.

[Gingerboy]

Very nice job!

[browniethewelder]

I have to ask, why did you use AC. I've welded with DCSP on cast Iron and cast steel and used EN 82 and it work just fine. But willing to learn something new. Thanks.

[kvwall]

I have to ask, why did you use AC. I've welded with DCSP on cast Iron and cast steel and used EN 82 and it work just fine. But willing to learn something new. Thanks.

Good question. Jody from weldingtipsandtricks.com used AC and I thought maybe it would do some cleaning like on aluminum. ?? I'm no expert so I thought I'd give it a try. I will say the tungsten had to be cleaned up twice during the process.