eps hardcoat materials?
what resin or mixture do I use for hardcoati EPS foam ?
is it resin, or poly clear coat like
you would get at the hardware store?
There are a lot of options for coating foam. You can do everything from fiberglass resins and epoxies to coatings made specifically for foam. It depends on your project needs (indoors, outdoors, display only, going to be handled, etc.), desired finish, and budget.
Hardware store resin should work for some applications.