TOPIC: Evinrude Paint Question

I'm refinishing the cowl of my '63 Evinrude Starflite III. I've done some automotive painting but this is my first attempt with fiberglass. So, not surprising that I have a question. I'm using Evinrude/Johnson/OMC zinc phospate primer in manufacturer spray cans. The color is olive green similar to the color Johnson used before switching to the dark red white used in the late fifties/early sixties. When I've done automotive painting, I would spray on the primer, let it dry, then wet sand it smooth 400 or 800 grit. If it needed more primer, I'd repeat. If not, I'd finish paint, wet sanding each coat with 1000 grit till satisfied. The OMC primer doesn't behave like automotive primer. It goes on the same, but it doesn't produce much slurry when I wet sand it. If I dry sand it (I've tried 180 and 200 aluminum oxide), the paint gums up the grit as if it was still wet. Should I expect the OMC primer to work like automotive primer? Should I not wet sand the primer coats and go straight to the finish coat? Or am I doing something else wrong? Thanks for the advice.

The zink based primers like zink chromate and zink Phospate sold by outboard motor manufactures are designed for the aluminum parts of the motor and not the fiberglass cowls. The purpose of a zink based primer is to allow the topcoat to adhear to the aluminum. When zink based primers are applied directly to aluminum they are generaly not sanded before applying a topcoat. For your purposes you can use a standard sandable polyester based primer, glazing compounds, and body fillers on fiberglass motor cowls and wet or dry sand to your hearts content. Good luck with your project. Brian

Thanks for the info. I was afraid it was something like that.