The "window" is if you dont want to have to sand between coats. If you exceed the "window", you need to scuff the paint to ensure the next material will adhere.
Many paint lines do not allow application over epoxy primer. This warning would apply to the "window" only and not be applicable if the epoxy is allowed to fully cure and then sanded/scuffed prior to applying top coat.
In other words, when applying subsequent material within the "window", you are relying on a chemical bond between layers. After the "window", you are relying on a mechanical bond between layers.
Last edited by DavidF; 03/02/2012 8:51 PM.
