TENACO® EPOXY 12-13 Primer has been field tested since 1964. It contains Zinc Phosphate pigment as the anti-corrosive agent. ASTM B-117 test for rust creepage away from x-scribe on steel panel: rating of 9 on a scale of 0-10. 0-worst, 10-best. It’s purpose is as a rust inhibiting metal primer which can be used with most any painting system — #12-13 Primer will not stain, shrink, or swell from sand scratches.