+x MarkMK - 7/13/2020 7:56:10 AMIf you're referring to GC50 itself, you can only apply a single coat, as it won't bond well to itself, unlike conventional polyester gel coatings (which shouldn't be used to make epoxy parts)Once applied, it can be left up to 24hrs and still bond okay to the epoxy. I have, on very rare occasions, left it a little longer and things appeared to be alright. Ideally, though, it is usually ready to go after a couple of hours at reasonable ambient temperatures.