I was wanting to know if anyone has ever used Northstar EP210 epoxy primer as a sealer for basecoat.

Have been using ep210 for a number of years for sealer when I end up with a couple sanded through spots in primer and using it on bare metal as well. It holds out rings on sand throughs and has great adhesion to properly prepared bare steel. 1:1 (ex355 i belive is the catalyst) with 10% reducer for sealer it lays down nicely.