On Monday, November 30, 2015 at 1:29:58 PM UTC-5, Ed Huntress wrote:

I think that welding cast iron has had enough written about it to fill
a book. But this is a subject on which I'd want to talk to an expert,
to fill in some of the questions that the books don't answer.

--
Ed Huntress

I think one of the problems is that each welding job on cast iron needs to be thought about and evaluated. In some cases the contraction of the weld material will not cause a problem. And example is when you are welding two pieces together. In other cases the contraction will put stress on the cast iron. Like welding a spoke that broke on a spoked gear.

Dan