The air dry clay takes about 72 hours to fully harden. Then, you can paint it, let it dry, and enjoy! (Remember: air dry clay is not waterproof/food-safe, even after painting).The ceramic clay takes between 10-14 days to completely dry, depending on size + thickness. Once hardened, it is ready for professional kiln firing (learn more about that here). P.S. There’s no rush to bring your ceramic clay to be fired. You can wait as long as you’d like.