Got a brand or pn that you use? The only non-catalyzed clear I can think of (leaving out the rattle can stuff) is an intercoat clear that is minimal build and designed as a protective layer for artwork/airbrushing so you can safely do tapeouts for the next layer of graphics. It offers no real protection to the elements to speak of, ie: no UV resistance. If this is what you are spraying, using this stuff as a topcoat with no UV protection, I would be concerned about how long it would last and having to do rework.
