Priming rigid

Does anyone have a recommendation for a primer (brush applied) for Rigid prints? I might have just been a bad jar, but we had a terrible time getting gray primer to dry on Rigid parts. Again, bad primer or maybe the glass content of rigid? Anyways, what do you’all use on Rigid?

You could use a shellac to seal it. I use spray Automotive Grey Primer for the best results but that’s on regular resin.