Head Material

hi, they are made of cast iron. for welding, use a 3/32 dia cast rod or use machinable nickle rod. do not heat the head up!!! weld at room tempature.
use a slag hammer and knock slag off, keep hammering on the weld area, this will stress releive it. weld about an inch at a time, knock off slag, let it cool to the touch, then weld again. this takes some time, but you will have a good repair. I've welded lots of cast iron this method, this is from a pipefitter.