My project is almost done with the sheet metal repairs and it's getting near time to start thinking about prepping for paint. I'm not equipped to spray base coats or clear. But I can spray epoxy primer and do the surface straightening. However, I can't shoot the entire car at once. So I want to spray smaller sections at a time. From what I've read, it's not recommended to apply filler over epoxy that's been sprayed beyond 7 days. So I'm looking for guidance how to handle this problem. I would like to get the entire car primed in epoxy (it's a mix of bare metal and e-coat right now), then start work with the filler. But there's no way I can do that in 7 days. What can I do?