It depends on the brand. The approach I take though, is I don't start a glassing job unless I know I can do wetout and all fill-coats in one long session, even if I have to get up during the night to apply a fill-coat.

Over-coating at the earliest possible moment has the added advantage of reducing the likelihood of blush.

It can strain relations with the wife, but it is worth it for the peace of mind, even if I occasionally have to get a piece of my wife's mind. 😄

I don't know what I'd do if someone brought me a completely cured wetout coat with no fill coats and wanted fillccoats added. I may be tempted to strip the whole lot off and start the glassing from scratch. That may be overkill though. Maybe a rub down with a scouring pad is enough. Epoxy has a small molecule, and doesn't need much roughness to get good mechanical adhesion.

Et