I've been trying out some 3/32" round TIG welding tungstens. They sharpen up easy with Steve Lindsays templates. So far they're working great in brass, copper, and very mild steel. I haven't tried them in anything even remotely hard yet. I cut each 7" piece into 3 sections, so that's 30 graver blanks for $20 or less. I grind a small flat on one side on an end for the set screw in the Lindsay sharpening template, and that also keeps it in the proper position in my Artisan Airgraver.
i bought a tig rig sometime ago. those electrodes may cut well, but should only be wet ground and sharpened. they contain nasties that do not belong in the lungs. you may want to investigate the matter a bit. jmho