Painting Problem Questions

All coatings whether it's primer to clear coat has a recoat window. Any longer and you have to "reactivate" it by sanding or using a scotch brite pad. I'm not familiar with any automotive primers. I am familiar with strontium chromate epoxy primers used on aircraft. Those are usually a three component mixes. Even some of the surfacers will recommend reducers. If it's thinned out too much it will dry out before it hits the metal. If it's real hot out when you spray will also affect it. Hope this helps.