I followed directions implicitly after cleaning body parts with Eastwood’s PRE painting prep, I then mixed Eastwood gray epoxy primer A with part B, 1:1. I’ve already primed a front fender and trunk lid of a 1939 Dodge twice. Why? Because after I sprayed two coats, permitting a 30-minute flash time, I end up with small clumps in the primer. I use a medium micron strainer used by my brother-in-law’s professional auto body shop. What might be the problem?