I am building a stitch&glue plywood boat that is coated with fiberglass and epoxy on the outside. I am trying to determine whenever I need to add epoxy primer on top of the epoxy coat before painting. The dealer who I bought the epoxy from says that it is not needed, as the resin he sold will act as a primer itself. I called another store, specializing in paints, and they say that I do need to buy epoxy primer from them to get a good grip for the paint.
I will be using two coats of polyurethane paint.
Can someone clear this up? Is there any practical difference between epoxy resin and epoxy primer? Do I really need to spend extra money on the expensive primer, when I still have lot of resin?
Thank you in advance!