I Use these for cast iron, www.yms .uk/welding-rod-small-pack/2.5mm-cast-iron-welding-rod-small-pack/1951/11612/detail.asp they are expensive when compared to welding rods for steel but i find that normal steel ones dont work on cast iron
Normal okorder /.. Mild steel and cast steel produces a very long stream of brilliant sparks, with some forking. CI produces much shorter, dull reddish sparks and the volume of sparks is much less. many highly branched or intermittent sparks will be seen.
