Hi Meyovaw,
Great question, welding cast iron can definitely be tricky!
When it comes to rod selection, it really depends on the job you are doing and the type of cast iron you are working with. Nickel-based rods like ENi-CI (Nickel 99) or ENiFe-CI (Nickel 55) are usually used to weld cast iron. They offer excellent machinability and reduce the risk of cracking after welding.
If cost is a concern, cast iron-specific electrodes like AWS ESt or even some low-hydrogen rods can work too but they require extra care including preheating the metal (usually around 500°F) and slow cooling to avoid thermal shock.
Also, try to keep your welds short and allow cooling between passes to prevent overheating the casting.
Let us know more about the piece you are working on engine block, pipe, old casting? That can help fine-tune the advice.
Best of luck and welcome to the forum!
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