[Burnit]

This is how I was taught, and it is only another method, I have not tried any of the other methods because the only place I worked at that repaired cast Iron was where I learned this from, so we had to do it their way. I never saw anything fail, the owner even repaired some old/rare Mopar block that had cracked from being frozen.

Again this is only another method, not right, wrong, better or worse, just what I know

We never preheated the part, because cast iron has so much carbon in it.
We would bevel out the crack and weld the joint with TIG using NiCu7 filler rod, more copper
in the rod than you normally see.

When welding it we didn't completely melt the base metal, we melted some of it
but didn't get a big fat puddle going, then add filler. So some of it was welded but technically
other parts of that same little area were brazed (the base metal never melted)

We would weld about 1/2" to 3/4" then stop and peen joint very well. we had old center
punches with handles welded on them, hold the point exactly where you want to peen and strike the punch with a hammer. Every visible part of the weld was peened.

Welding just a little at a time and keeping the thing as cool as possible.

So there are a lot of similarities with other peoples methods, this one just stressed keeping it cool.

The guy who I learned this from was a weld engineer at Allis-Chalmers for a looong
time and holds several patents for welding process'