Resin parts, painting question.

Aside from giving your top coats some teeth, it also helps to highlight any flaws or imperfections in the resin. It's a good idea to do so.

I always prime resin for the simple fact that even cleaning them thouroughly doesn't guarantee paint adhesion.  Resins, if incorrectly cured or mixed, can bleed for weeks or even months (sometimes years).  If the bleeding is minor, primer is usually enough to fix the problem.  I prime just to be on the safe side as minor seepage isn't always immediately apparent and who needs it ruining a paint job months after you though the job was done.

On a seperate (but sorta relelvant) note, if the bleeding doesn't stop, you need to drill out the area and fill it with a mix of CA and talcum powder.

-Fred

i dont prime all my resin kits the problem you run into is if you didnt clean the release agent off good enough from the resin parts soak them real good in a cleaner like simple green then brush and rinse them

if you are using acylics first you may want a primer coat as i have seen it not have enough tooth on bare resin