I started off sanding the Poly Fiber Smooth Prime that I had placed on the day before. I had put a thicker coat and felt it would fill a majority of the pinholes. So like other epoxies, primers, and fillers you sand to remove them and hope that the pinholes are filled. Well the cowl surface was very little better off.....I started rethinking if I needed to change processes.
I called Poly Fiber and couldn't speak with technical support and was promised a call back. So I decided to tackle the cowl inlet ducts. I had covered them with micro in order to blend the seams and transitions and will actually lay some paint on them to make them slick as possible and hopefully with as little airflow disturbance as possible. Micro sands easier than flox but still takes a lot of elbow grease! It took me the rest of the work session to get the ramps sanded.
Got a call back from Poly Fiber. So Vans instructions are not correct as they say use the Smooth Prime right out of the can with a squeegee. Poly Fiber told me to get some 4" foam rollers and then apply the Smooth Prime without diluting from the can. They said it needs 6 coats totally. Roll each coat and allow to dry completely.....perhaps 3 hours or so depending on temp/humidity. After applying 3 coats DRY SAND with nothing rougher than 400 grit sandpaper. Just sand till smooth and do not sand to fiberglass. Then apply three more coats of Smooth Prime and repeat process. The pinholes should be totally gone and when totally dry you can use an epoxy primer to coat the cowl.....so we will try it again!
