So I'm thinking of possibly using Amershield VOC POLYESTER ACRYLIC POLYURETHANE over their Epoxy primer (Amershield 370). Do I have to seal the concrete floor with some sort of sealant before applying the primer and topcoat?
No. The epoxy is a sealant. If you apply some other sealant on the concrete before hand, it will prevent the epoxy from adhering. You would need to grind the concrete in order to remove the sealant before applying the epoxy.
