Rods for welding cast iron

[IvanBlock]

My two cents worth on welding cast iron and Aermotor gear box tail pin holes. About ten years ago probably more I bought 10 pounds of Certanium 889SP Cast Iron rod, cost me something like $485, thought I had lost my mind. I don't use often but it works great. Takes a little time to learn how to use, like it takes more amps than regular 6011 or 6013 rods (about 135 amps for 1/8" rods) Lays down a real nice clean deep bead. Needs minimal preheating or none at all for smaller welds. For slower cool down I just drop the part into a garbage can of ash and cover it. For welding wollowed out tail pin holes I use the 889 rod. Now for my trick or secret I use solid carbon (see attached picture) It can be machined to the proper size for the tail pin (3/4" for 8' gear boxes) Place it in the correct position and wedge it in with a small piece of metal and start filling the void with the welding rod. The carbon plug can stand the heat and will leave the hole size you want. After cooling you can gently tap the carbon plug out and reuse. You might have to do a little die grinder work to aline the top and bottom holes. Now as for the carbon, carbon fiber will not stand the heat. The carbon I use is salvaged from the very old style 6 volt electric fence batteries, each one has two carbon rods about 1" x 6" long. Finding these old scrap batteries might be difficult, I happened to come across a guy that had part of a barrel full. Try it if you can you might like the results...

[windybob]

Thanks for the hints. I sure cannot do that rod, but I've always had good luck with NI99.

[Kansas Rust Buzzard]

When I was a kid we would buy telephone batteries at farm sales to take the carbon out for this, don't see them much anymore but every farm used to have an old wood telephone in the house and one in the milking shed or shop.

[JBarker]

all good information from all, thanks