Notice the portable nomad welding table...a good way to do small welding jobs like this..
Got an email the other day about tig welding cast iron. The part was a part from a old water well hand pump that was broken in half
I asked for a picture but gave some preliminary advice that kind of applies to all cast iron welding.
So here is the list of tips I sent for cast iron welding...
good luck to you
• prep and preheat are common to any method so i will go there first
• you will probably want to clean the weld area about 1/2" back from the break to clean shiny bright metal using a grinder, or burr
• you may need to leave the fractured surface alone for the purpose of aligning it back straight.
• then figure out a way to hold the pieces together lined up like they broke and
• get a few small tack welds
• groove out a bevel everywhere you can to get some depth of penetration
• preheat using a torch. till the shiny bright metal turns blue and purple or even hotter
• weld using stick with ni rod for cast iron (high nickel) or even 312 stainless stick will probably work and is much cheaper
• or tig weld using 312 ss or silicon bronze filler or aluminum bronze filler (i like to use AC tig for aluminum bronze) dc will work for everything else.
• let cool slowly...it might even help to reheat with torch immediately after welding and let cool slowly
He chose to use silicon bronze filler rod and he tig welded it.
Cast iron welding repairs like this on small parts usually work out .
Its the bigger parts like engine blocks, exhaust manifolds, etc that are much more difficult.