I try and use epoxy as much as possible, but sometimes on small collision jobs, there is not enough time to spray epoxy, wait 24 hrs., then apply filler. In that case, I apply epoxy over the metal and filler before 2K. My question is the time needed between epoxy and 2K. I am sure the times vary depending on temperature and the application of the epoxy, but what is safe? Sometimes it works out that a repaired area is ready for primer before I go home, and I will put 1 unreduced coat of epoxy on, then spray 2K the next morning. Ideally, I like to let 2K sit overnight, but I don't like rushing the 2K over epoxy, either. I have used a light to medium coat, reduced 25% or so, over metal spots and then shot 2K an hour later, but I'm not sure if it is good practice. I did have epoxy edges "lift" once. The repaired area was epoxied, then 2k an hour later. The repair sat outside for 3-4 days while I waited on parts. When sanded, the 2K edge ended up inside the epoxy edge, and when base coat was applied the epoxy edges "lifted", for lack of a better word. SInce then, I have kept the epoxy covered with only a 2K edge showing, and it hasn't happened again.