It usually takes about a minimum of seven days to dry, but we recommend that you leave it for two weeks to be on the safe side; in order to see if it's dry, press it with a bit of pressure to see if there are any imprints left, if there isn't, then it should be dry and ready to paint. Oftentimes people prefer to prime the surface before adding the glazing compound; it should adhere to the primer, speeding the drying process. However, letting it dry naturally is the best option.