There are "special" rods... The normal ones are just high nickle content, then there are the "secret" special ones that promise the world but can be used with a hair dryer ......the real cost in what you were quoted is in labor. To do a real good cast iron weld requires a good preheat and carefully post repair heat treat of the whole area. Cast is very prone to cracking after the repair. I happen to be staying with a relative that is a certified welding instructor....I will pick his brain tomarrow. I'll let you all know.