I use "air hardening drill rod" as welding rod and a torch to build up parts that have to be tough as woodpecker lips on gunsmithing projects like repairing a broken firing pin tip, etc. Apply it with a torch and shape it with a grinder, as it absolutely can't be cut with machine tools. Once the part is ground to the proper shape, then I "draw" the finished piece by heating it in the torch flame to a straw color and letting it air cool to avoid making it brittle as glass.
Jerry
