: . Most polyester resin is for laminating and is made
: without wax so it never cures hard, it's not supposed to. With
: wax added it'll cure hard.

Just to clarify, laminating polyester resin IS supposed to cure hard, but it will not cure in the presence of air. It is meant to be used in molds that seal it from air exposure. Adding wax, or buying resin that contains wax ("finishing" resin), creates an air barrier on the surface that seals out air so it will cure hard. You can do the same thing with laminating resin by covering it with Mylar or polyethylene sheet.