Question for Eastwood: I completed all the metalwork and fabrication, and used lead for all the body work. The finished result after priming was far from perfect so I used your Z-GRIP to apply a skim coat over everything. Now it looks better! However, after I primed and sanded, there are still a lot of sanding scratches and minor flaws the primer did not fill. So I purchased two quarts of your Slick Sand. After I spray this on I will re-sand with 400 wet. Will that product be the final coat of primer I need, ready for top-coat, or is it neccassary to re-prime with a etching primer?