The Compleat Sculptor
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  Statuary HYDROCAL® Brand Gypsum Cement



  • Produces harder and stronger casts than HYDROCAL® Brand White Gypsum Cement.
  • Basic gypsum cement with excellent plasticity development.
  • Recommended for both solid and hollow casting.
  • Very white in color and can accept colorants easily.
Technical Properties English Metric
Use Consistency (parts of water by weight per 100 parts plaster ) 40 40
1 Hr. Compressive Strength 3,000 psi 6.9 MN/m2
Dry Compressive Strength 6,500 psi 44.8 MN/m2
Maximum Setting Expansion 0.250% 0.250%
Wet 113.0 lb/ft3 1.81 g/cm3
Dry 96.0 lb/ft3 1.54 g/cm3
Set Time (Machine Mix)* 25-35 min. 25-35 min.
*Other set times may also be available. Call your sales representative for more information.
General Directions and Guidelines

  Preparing the Mix Use potable water at temperatures between 70° and 100°F (21° and 38°C). Since variations in slurry (Statuary HYDROCAL® Brand Gypsum Cement and water mixture) temperature produce variations in setting time, it is important to keep both Statuary HYROCAL Brand Gypsum Cement and water in a stable temperature environment prior to use. The higher the temperature of the slurry, the shorter the set time. See the graph below.

  Measuring Weigh both Statuary HYDROCAL Brand Gypsum Cement and water at the recommended use consistency for each mix (see Technical Properties above). The water-to-Statuary HYDROCAL Brand Gypsum Cement ratio is critical because it governs all physical properties of the final cast piece.
  Soaking Sift or strew Statuary HYDROCAL Brand Gypsum Cement into water slowly and evenly. Do not drop handfuls of Statuary HYDROCAL Brand Gypsum Cement directly into the water. Allow soaking for 1-2 minutes. Statuary HYDROCAL Brand Gypsum Cement should be fully dispersed in the water prior to mixing. Small batches require less soaking than large batches.

Mixing the Statuary HYDROCAL Brand Gypsum Cement slurry is one of the most important steps in producing Statuary HYDROCAL Brand Gyspum Cement casts with maximum strength, hardness, and other important properties.

Mechanically mixed slurries develop uniform casts with optimal strengths. Statuary HYDROCAL Brand Gypsum Cement can be mechanically mixed through both batch and continuous processes. Proper blade and bucket dimensions are important for obtaining the best batch mix. Longer mixing times result in higher cast strength and shorter setting times. The relationship between mixing time and both compressive strength and setting time is shown below.


To prevent air entrainment and provide a uniform, smooth surface, careful pouring of the slurry is necessary. Agitation of the filled mold is a further step used to prevent air at or near the surface of the cast piece. Whenever possible, the slurry should be poured carefully in the deepest area so the slurry flows evenly across the surface of the mold.

Pouring a large amount of slurry directly on the face of the mold may result in slight densification of the cast at the point where the slurry strikes the surface of the mold.


All casts should be dried as quickly as is safely possible after manufacture so that maximum physical properties can develop. Dry to a constant weight.

The best drying rooms or ovens provide (1) uniform and rapid circulation (minimum of 15-30 fps) of air with no dead spots having little or no air movement, (2) equal temperatures throughout the entire area, and (3) provisions for exhausting a portion of the air while replacing it with fresh air. High humidity surrounding the drying room or oven inhibits the efficiency of the drying because the air pulled into the room is incapable of picking up much moisture from the cast pieces.

The maximum temperature at which Statuary HYDROCAL Brand Gypsum Cement casts are safe from calcination is 120°F (49°C). With substantial free water in the cast piece, higher drying temperatures can be used without difficulty. As drying progresses, the temperature must be reduced to prevent calcination. The safe drying zone is in the shaded area of graph (below, right). Before removing casts from the dryer, the temperature should approach that of the area around the dryer to prevent thermal shock.

  Storage Keep in a dry, stable environment indoors. Do not stack more than 2 pallets high. Keep from drafts. Rotate stock.

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