Contact the Deep Rock people given in a previous answer. A friend purchased one of their small well drilling rigs and I regularly coated his drill bit using the carbide + powdered brazing material from Deep Rock.
Dead simple to do, as you've stated - heat up cherry red using an oxy / acetylene torch and dip into the powder. He was drilling into rocky area and after some trial and error, we found that "double dipping" (two coatings) made it last longer between treatments.