Originally Posted by FHG1382
are you sure about that?
I do a lot of cast iron repair and the cast filler rod I get for gas welding, (with a flux), is square in cross section. You can buy fluxes from your local supplier or you can make your own from anhydrous borax, silica sand and iron filings can be thrown into the mix as well. I use this last blend for forge welding, (hammer and anvil and a coal fire).
Do you have an electric welding machine capable of DC welding current? If you do try some 'Avista' (sp?) rod.