Cast iron welding used to be a involved, difficult and often unsuccessful process. Boy, has that changed! My friend Tony Rotta, who is the maintenance manager at a local canning plant, was able to do all my cast iron welding with the same ease and speed I'm used to seeing when welding mild steel. Gone are the days of heating large pieces, chasing cracks and brittle welds.
The secret is new (at least to me) rod technology. Tony used Cronatron #211 Universal Cast Iron Machinable rods in an ordinary arc welder. They may be used in AC or reverse polarity DC mode. Tony says the technique is not noticeably different from working with mild steel. Preparation is the same, grinding a good deep "V" and cleaning things up. It is also a good idea to drill the end of the crack to keep it from traveling and reduce the stress at that point.
He welded a crack in one of my wheels that started at the axle hole and travelled in a half-moon shape away from the center and back around towards the axle hole. He laid three beads in ground out "V". After grinding the welds back to match the contour of the hub, the only way you can detect them is that they are smoother than the surrounding cast!
Check with your welding supplies dealer for more details.
