painting inside of brake backing plate with ceramic caliper paint

[painting inside of brake backing plate with ceramic caliper paint] i.e., The US $14.95 US caliper paint kit at Advance Auto v . . .plan to paint rear brake backing plate inside-and-out on '71 Westy. wish to avoid any mistakes that would "flake off" in my brakes later. have cleaned rusty surface with brake cleaner and brass brush. tried pre-treatment spray on rust converer, but judged that to be a mistake and scraped that off with a brass brush. considering naval jelly and brass brush. Is P.O.R 15 or equiv indicated before application of brush-on caliper paint? v I have some cheaper spray-on brake drum paint for the drums and exterior of backing plate.

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