For best results, the following guidelines should be observed

1. A form used for casting can be wood of steel. In either case, it must be watertight and thoroughly oiled with grease or paraffin for easy removal of the formwork.

2. The form vibration should be moved in the upward direction. When withdrawing the vibrator from the castable, it should be drawn up slowly to ensure that to holes or channels are left behind. The mix contains insufficient water if the vibrator leaves holes.

3. Excessive vibration will be indicated by the forming of water on the surface. This should be avoided since it will segregate components and weaken the castable. Furthermore, the forming of fine cement granules on the surface may cause explosion during the heat-up

4. To permit free water evaporation, the surface should not leveled after casting