Cure and check

Epoxy cures by a chemical reaction that runs on warmth. At 70 to 80 F most coating and casting resins can be demolded after about 24 hours and reach full cure in 72 hours; deep pour resins take 24 to 72 hours to demold and 5 to 7 days to finish. A cooler room slows everything: as a rule of thumb, 18 F cooler roughly doubles the time. The epoxy cure time chart has the numbers by resin type.

UV resin is cured with light of 365 to 405 nm. A clear layer about 2 mm thick takes 30 to 90 seconds under a UV-LED lamp and 2 to 4 minutes under an older tube lamp; direct sun does it in 5 to 15 minutes. Turn the piece and cure the other side. Color and thickness add time. See the UV resin curing time chart and curing without a UV light.

Then check. Press a fingernail into an edge: cured resin does not take a mark. Epoxy that is tacky after a day in a warm room points back to the ratio or the mixing. UV resin that is hard but has a sticky film is usually fine and wipes clean with alcohol; sticky UV resin sorts the cases. A piece that is hard but bendy mostly needs more days.

Ready to move on when: The surface is hard and tack-free, and a fingernail pressed into an edge leaves no mark.