Attached are pics of the 2nd Rolls Royce exhaust manifold I repaired using the "Cold Welding Cast Iron With MIG" process I have used with complete success.
This manifold was cracked thru the inside flange & the manifold had a severe warpage. After wire wheeling clean, I beveled each side of the crack & extended a bit past the end of the crack. The weld parameters were: .030/309L wire(.01carbon content), 98/2(AR/CO2) @ 18cfh, 90-100A. I tacked each end of the crack & peaned to start. Then I ran a 1/2" bead(pull not push), peaning immediately after welding to relieve the weld. The casting got only warm to the touch & this is the secret to eliminating the dreaded "tinkle". After 15 min. or so back to room temp., I did the 2nd weld on the opposite side, peaning again. I repeated the process till the entire crack was filled nicely.
When I was finished, I took the manifold to the automotive machine shop that does all the machining on the race engines my brother builds. Their work is superb & they have a very extensive machining operation. They surface ground the manifold back to true flatness.
Here's the pics....(9).... gonna need (2) posts to get them on, so give me a couple xtra minutes. Thanks....