For a mixture, the recommended ratio of water to gypsum powder is approximately 1:2, but the amount may vary depending on the temperature of the water and the weather conditions at the time. Do not mix or stir the plaster directly with your hands!!! Steps:

1. Add water to the mixing tray.
2. Pour or sift a small amount of gypsum into the water, and gently mix with a spatula.
3. Tap the sides to vibrate and release air bubbles.
4. When the mixture becomes smooth, uniform, and light grey in color, it can be poured into the mold.