Regarding Welding Electrode

Pre-heating, with a torch if possible, also helps. Heat the entire casting to 400^oF - 1200^oF, the hotter the better, so that there is less differential in temps of the weld and the casting. Cast Iron will crack in the cooler areas when cooling if the whole piece, including the weld, does not cool evenly.

Another alternative is to weld only short sections at a time, such as 1/2". Weld, chip, let cool for a few minutes and then repeat this. This allows the heated area to "cool" evenly between welding the short beads.

Can't reference any books for this for you. It was taught to me by a very excellent welder who could repair almost everything but a broken heart. I have seen it in books, probably one of the rod manufacturers handbooks.

I can't arc weld any more because they implanted a defibrillator to help the heart so I threw out most of my welding references to reduce the temptation to weld. Arcing can cause it to activate and Oh What A Shock! I mention this because I don't want you to go through what I have and everyone should see a cardiologist when they reach 40 years old. If for no other reason, get a base line for future use if needed. Please take care of yourself. Dying ain't no fun!

Good Luck, Old Salt