Halftime 4BONDING Plaster Accelerator is a chemical additive for use with bonding plaster. The additive speeds up the curing process of the plaster by speeding up the chemical crystal formation that causes plaster to set or harden. Halftime 4Bonding is recommended for shortening the setting time of bonding plaster. Halftime will shorten the setting time to 20 minutes, depending on the ambient temperature and relative humidity of the working environment.