I do a good number of them and always use my mig welder. The stick seemed to be too hot and melted the tang off or sticks to it. The mig fills in a nice solid bead. Do it before HT, and be careful especially with O-1, it air hardens and gets real brittle. HT and temper evens that all out. Don't harden the whole tang, I only do up to the ricasso.
Rudy