Regarding the sunlight issue,I painted a tow hitch on my work truck about a year ago,the finish of the POR-15 has stood up to most things including the rock salt our roads dept. throws on our roads every winter! :mad:
The gloss shine has deteriorated somewhat but the overall condition of the paint is still good.
As others have said,to maintain a good gloss you should overpaint the POR-15.They also manufacture a chassis paint suitable for this application.
