Plaster and joint compound mix, known as setting-type compounds, require water. The different types of setting-type joint compounds require various water-to-mix ratios and take different amounts of time to harden.
Setting-type joint compound is usually a dry mix and comes in a bag or bucket. The bag or bucket will include the ratio of water-to-mix. The amount of mix and the amount of water depends on the size of the job.
The type of compound also determines the length of drying time required.
- "Easy sand" often takes 45 minutes on average to dry to complete hardness.
- All-purpose compound dries in 24 hours.
- Topping compound for quick fill of cracks comes with five- to 20-minute drying times.