Is it an epoxy primer?
I am no paint pro of any sort, but primer by definition is meant for stuff to stick to it and porous. . Paint, dirt, water, grime etc...
I have used the hot rod flats from TCP.. its cheap and easy to lay... BUT
Semi glosses and Satin paints DO tend to be a little harder to get an even coat with. The first time I did it I kept getting blotchiness. I figured out it was from going over the same spot more than the rest of the panel and hence getting more gloss on it... at $100. It will buy you a few years and what's to lose?
