You are probably remembering Eutectic, which is a company that makes and sells many types of welding rods and welding supplies. I am by no means a welder, just a hack, but I have watched a lot of automotive and equipment cast iron parts repaired and also a whole lot of parts ruined trying to repair them. From what I have seen over the decades, if you are not a regular cast iron welder with lots of experience with welding on cast iron, the best work I have seen by equipment mechanics and garage tinkerers has been brazing the cracked work with brass rod after Vee-ing out the crack so it is accessible to really clean well, using lots of the correct flux, carefully preheating the entire part, laying in the brass, and then making sure the entire part cools very slowly and evenly. If it is not cracked when it is cooled down, it will probably last indefinitely, and will be as strong as the parent cast iron.