I have been experimenting with different glues over enamel paint. Anything with MEK in it will cause the enamel to curl. Fletch tite plat. is what I recently tried and it curled my enamel spray painted caps. Super glue type glues (cyanoacrylate) work very well over enamel. I have used loctite gel and professional, gorilla, and goat tuff. For me, the gel was the most user friendly. Only issue I found is the drying time. It's best to not rush it and leave them clamped for 20 or so minutes.
My next test will be fletch tite over spray lacquers or krylon for comparability.