I believe I read somewhere that Por15 itself is sensitive to sunlight...Don't they sell a paint that goes on as a topcoat?
I know Dad used it on his frame and it(Por15 only) turned out great.He used it on bare steel.
Yes Weimer, Por-15 is UV sensetive on its own, it will fade or change color in in direct sunlight. Por-15 recomends you use a topcoat on anything that will be in or could see direct sunlight. The have a variety of topcoats to choose from.