you could try that stove black, heat proof paint for painting wood burner fireplace things & flue (chimney) pipe. The can I have is a matte/satin black with little sparkley things in it (almost a gunmetal black) you spray it on and have to cure it with heat (oven) Might work? Auto shops also sell 1500 degree black spray paint cans (for exhaust pipes/headers)
Might be worth a try? Bake it on in an oven
