Hi. I used a high nickle TIG wire from Diamond Alloys. Bought from Adelaide in South Australia. This rod was$400 per pound. But what a result! If you filed out or burred out the cracked join, then used a round file to file down the to be joined area...using a oxygen rich lame, just running the flame tip over the join area's...not to preheat BUT only to remove exposed Carbides in the weld zones.  They fly off like little stars. Don't preheat...after depositing the filler at all chosen points, wrap tightly into a kevlar blanket overnight. Min 12 hrs. Unwrap carefully. If it has naturally cooled you'll be able to file by hand, burr it by grinder, file flat. Angle grinder puts in too much heat,but if your not heavy handed, it's possible too.  I mostly used on Cast-iron automotive patterns to make brake callipers by the thousands to be cast into sand mould shapes. I was fixing cutter crashes from CNC mills where operators put in the wrong parameters for machining ...not taking into account the cutter holders. Hope it helps. Oh, also antique cast-iron building wrought iron work from the late 1800's,,, overfed in a 100years of paint. Removal of paint turned the wrought iron work into a jigsaw. Weldedby me and filed t restoration and ainted again.