I've had cast iron brazed before and it's lasted some 30 odd years. The jack handle from my 78 Toyota Land Cruiser.
Anywho, a local machine, welding, fabrication shop says they can do it but it will cost me around $70.00 for the two breaks on the first frame.
I've been told by another welder that's because it takes a special rod to do the job and make it right.
Joe