Mixing Instructions

General Directions

Below is an at-a-glance plaster mixing guide. For additional information on USG Plaster mixing procedures, visit usg.com, see the individual product submittal sheets, SDSs and IG503 USG Plaster Mixing Procedures or call 800 USG.4YOU (874.4968).

Recommended Equipment

  1. Scale – accurate to at least 0.1 units
  2. Mixer, motor and container – sized correctly for product used
  3. Sufficient motor RPMs for mixing
Measuring - Step 1 Weigh the water container to 0.1 units. Add appropriate water amount to container.
Measuring - Step 2 Weigh the plaster container to 0.1 units. Add appropriate plaster amount to container.
Sifting Carefully sift the plaster into the water. Avoid adding large amounts at once. Never add water to the plaster.
Soaking Allow the plaster to soak undisturbed for 2 – 4 minutes depending on batch size.
Mixing Mix for 2 – 5 minutes depending on batch size, mixer RPMs and the product recommendations/requirements.
Pouring Pour a thin stream of mixed slurry in one corner of the mold. Allow to flow across mold surface to avoid air entrapment. Vibrate/agitate the mold to release trapped air.
Demolding When the material has appropriately set, carefully demold. Demolding too soon may damage the casted piece.
Finishing Immediately after demolding – trim, patch and scrape as necessary. The piece is now ready for oven drying and final decoration.

Product Categories