Flowcoat and Gelcoat
are basicaly ester resin with pigment in it. Once the original layup
has reached full cure, any further applications of resin only stickk to the surface. When I said "new", I was refering to it being layed and only starting it's initial cure. During initial cure, any further applications bond to the layer underneath it and the entire layup
becomes one solid layer. Ester Resins are very poor at "sticking" unlike Epoxy
Issues can occur when a layer has been allowed to fully cure for several days and then another layer applied. However, it's not like the flow coat is structural. It is only a coating, so not so much of an issue. However, I would still give it a wipe down with a solvent. Ester Resins have a natural wax substance that occurs on the surface and this needs to be wiped down to ensure the best adhesion of the flowcoat.