Im the powder coater this thread is referring to.
The factory finish is an epoxy paint. I will not ever powder coat over an existing finish, and certainly not this finish. There are several reasons. Firstly, simply being, powder coat is designed to go on top of a metal substrate. A substrate that has been prepped (in this case stripped and sand blasted, the sand blasting provides a profiled surface to anchor the powder).
Secondly, these powders are cured at 400F, a temp that would structurally weaken the epoxy paint. Powder is TOUGH...but it it is sitting on a substrate that has been fried, its no better than paint and probably much weaker than the factory finish.
Third reason is the surface profile of the finished product. The epoxy paint serves as an insulator to the metal ring. Powder coat is applied with electrostatic energy. The powder being charged and the part being grounded. Shooting over an existing finish creates charge build up in the powder particles, which does not dissipate. Just as your hair stands on end when you get a static charge, the powder particles "stand". While this isn't a big deal to many powder coaters, I am constantly chasing orange peel free or minimal orange peel finishes. Powder is inherently "peeled", which is really its big and only disadvantage against paint on metal parts.
Fourth. In order to inlay the red lettering, I need deep and clean-edged recesses to lay powder in. The factory finish is very thick and sort of "fills in" the lettering. After a base coat, there would be little depth left to inlay the accent color.
Can you coat over existing finishes with powder? Sure. Will I? Never.
