Bill really think about epoxy primers. I can't think of a single advantage to powdercoating and I can think of several powder coated items that show what a bad choice it is. My Leer truck topper handle is powdercoated, after two years it had to be replaced due to the powdercoating came off and it corroded. Any trailer hitch you see is rusted long before the vehicle has problems. The powdercoating fails at any sharp edges and the corrosion begins on the exposed metal. The Tig welder in the shop is powder coated and it is coming off in sheets. If you want to do the job one time and have it last forever and cost less, go with epoxy primers, not powder coating. There isn't an aerospace manufacturer out ther powdercoating anything, nor have they ever powdercoated anything. Today they all use epoxy primers to protect their structures, some of which have NO lifelimit.
I know this will open up a big debate, but I will never powdercoat anything and nobody I know will ever use it either. There just is no advantage to it.