I have an old log skidder which has a long (around 24 inch) crack line running most of the length of the water jacket which is cast into the block. It was repaired years ago by the previous owner with JB Weld epoxy and has mostly held, but now the epoxy is giving way and some coolant is leaking out. It would be difficult to get this to a professional for repair due to it's size and weight, although I will look into getting someone to come out to where I am. I have an old 200 amp AC stick welder, a Miller 175 MIG and do not have an Oxy/Ac rig, although I may get one for this if recommended.
I know welding /brazing cast iron has been covered before, but I'm perplexed at how to repair this. First, I assume the block is cast iron. If I weld it with cast iron, high nickel content rod, how could I preheat and slow the cooling down on such a huge heat sink? Seems from what everyone has discussed before, I could crack it worse if I don't do this properly. So then, what about brazing? Would this hold under this application, and how difficult would it be to do? If all else fails, I may just grind the JB Weld down, clean it up and apply more epoxy, but this really goes against my nature. Anyway, sorry for being such a nerd on this one - its just something I haven't encountered before and I don't want to muck it up. Thanks!