Thanks guys. That white undercoat works good with red too. That's how I figured it out years ago. I was making the old Testor Gee Bee and had filed off the raised details so I sprayed on white to spot anything that still needed sanding. The plastic was a medium gray color and I hadn't sprayed white on the cowling so it turned out darker and a little blotchy. No mater how many coat of red I put on it it was still darker so I finally sprayed white, then red, and it matched.