When giving discharge instructions to a 24-year-old client who had a short-arm cast applied for a fractured right ulna, the nurse recognizes the importance of telling him that the drying time for a plaster of Paris cast is approximately:

Synthetic cast materials harden in 3-15 minutes. Weight bearing is permitted in 15-30 minutes. Drying time for plaster of Paris is about 24-72 hours. (B, C) Plaster of Paris cast materials are heavier than synthetic materials and require a drying time of 24-72 hours. Synthetic materials dry within 30 minutes. Plaster of Paris cast materials are heavier than synthetic materials and require a longer period to set and dry. Even though setting time (hardening) is only 3-15 minutes, the drying time for plaster of Paris is 24-72 hours. This depends on the size and thickness of the cast, exposure to air, and humidity in the air.