6x6 Peterbilt 379 tractor build

[Rimrock]

I personally go for a primer especially developed for plastics, or etch primer, as first coat. The shapeways prints have a corned surface, maybe it helps standard automotive primer to stick better, compared to on a smooth plastic surface. I avoid standard metal primer on the prints myself, but if someone have good experience with it, that's great, just stick with it.