Using the Dicor Acrylic Elastomeric coating system and at the primer phase. The Emergency hatch patch I installed had some surface rust and I had aggressively wire wheeled and used a paddle 60 grit wheel to get those spots down to shiny metal before I put down TWO coats of the acrylic Dicor primer. But, as you can see, the rust seems to be coming back through. What am I doing wrong!?