Painting Resin

I already posted in the past about getting my hands on a 1/32 scale "Scratchbuilders TBM Avenger" an all Resin kit. This is the first time I ever worked an all resin kit. It's kind of hard, but fun. That's what this hobby is all about. Anyway, I was wondering if anybody out there has ever worked with resin. I started painting this plane with an air brush, using Model masters paint. It doesn't seem to stick on some parts of the plane. It worked great on the puddy spots. I cleaned the plane before painting. Does Resin need some kind of primer??