Free resin curing timer for epoxy and UV resin projects. Demould at 8–12 hours, full cure at 24–72 hours. Track gel time, demoulding, and post-cure stages.
Standard 2-part epoxy: gel time 45–90 minutes, demould at 8–12 hours, functional at 24 hours, full cure (maximum hardness and chemical resistance) at 72 hours. Fast-cure formulas demould at 4–6 hours. Temperature significantly affects cure — a 10°C increase roughly halves cure time.
Gel time: the point at which mixed resin transitions from liquid to a non-flowable gel. You can no longer embed objects or correct surface imperfections after gel time. Cure time: the point at which the resin reaches its final hardness and can be processed (sanded, polished, drilled). Demoulding falls between these stages.
Scratch test: attempt to scratch the surface with a fingernail. If no mark appears, it is hard cured. Soft or tacky surface indicates incomplete cure. Resin that never fully cures usually indicates incorrect mixing ratio — the standard is 1:1 or 2:1 by volume or weight, strictly as specified.
Optimal cure temperature: 70–77°F (21–25°C). Below 65°F: resin may not cure completely or may have a permanently sticky surface. Above 90°F: risk of exothermic reaction and yellowing. Keep large pours at room temperature and avoid placing in direct sunlight during cure.
Causes: incorrect mixing ratio (most common), unmixed resin components, too-cold curing environment, UV-cure resin not exposed to sufficient UV light, or inhibited cure from certain materials (many natural materials contain tannins that inhibit epoxy). Sticky spots often indicate incomplete mixing.