My take is everything short of the clear, whatever else is applied atop of the top layer, evaporates. Becoming another layer of patina! Enjoy your builds and make it look like you want, how you see it. P.S. whatever is under the paint, between the metal and the primer or early paint, continues becoming patina, even under clear, so your grandkid will have to reclear it. "Time waits for no one, and it won't, no it won't, wait for me" - Rolling Stones