Some primers do need to be topcoated within a certain time frame or they get too hard for a topcoat to adhere to.
The primer used on pre-primed materials does not fal into that category.
Nail it up, putty the holes, scuff sand the entire surface, then topcoat twice.
Careful with that MDF dust...it'll kill your lungs.
© 2017 Renovate Your World LLC