I havedecided to use por15 on my engine baybut have one question for any one who has used this product before. Do you think i will be able to spray a semi flat black paint over top of the por15's gloss finish with out it reacting, cracking, separatingwith each other.??

 

i believe they offer the por15 paint in semi flat too

 

In my experience, the por 15 finish/sheen is uneven and should be topcoated in visible areas. I am using it on my engine bay as well. You will have to sand cured por 15 to get topcoat to stick. The easiest way to do it is to get the por primer. It is made to be compatible with the por 15, then you can topcoat that. However, to avoid sanding, you need to follow the directions. You have to spray an initial dry dusting of primer on the fresh coat of por 15. This way the primer bonds to the por 15 chemically. It pretty straight forward. Sanding the cured por 15 to prep for topcoat is a pain in the a** and it is a must to topcoat cured por 15. Try it this way, much better.

You can read the direction on the por 15 websight.

Good luck.