USG Statuary Hydrocal

Article number:	47600B
Availability:	In stock (80)

USG Statuary Hydrocal® Brand Gypsum Cement is a good multi-purpose product for people
looking to upgrade from a standard plaster product to one that has a higher degree of hardness
and impact resistance. USG Statuary Hydrocal Gypsum Cement is designed for solid and hollow
casting and is ideal for giftware and lamp base applications. USG Statuary Hydrocal Gypsum
Cement is compatible with numerous color pigments. If information for a specific use is needed,
please contact your local USG Sales Representative for further assistance.

MIXING INSTRUCTIONS

Use potable water at temperatures between 70 °F and 100 °F. Because variations in slurry (USG
Statuary Hydrocal Gypsum Cement and water mixture) temperature produce variations in set time,
it is important to keep both the USG Statuary Hydrocal Gypsum Cement and water in a stable
temperature environment prior to use. The higher the temperature of the slurry, the shorter the set
time. Conversely, the lower the temperature of the slurry, the longer the set time.

Weigh both the USG Statuary Hydrocal Gypsum Cement and the water prior to use for each mix.
The water-to-USG Statuary Hydrocal Gypsum Cement ratio is critical because it governs the
strength and the density of the final cast.

Sift or strew USG Statuary Hydrocal Gypsum Cement into the water slowly and evenly. Do not drop
large amounts of USG Statuary Hydrocal Gypsum Cement directly into the water as proper soaking
of the USG Statuary Hydrocal Gypsum Cement may not occur. USG Statuary Hydrocal Gypsum
Cement should be fully dispersed in the water prior to mixing. Small batches require less soaking
time than large batches. See USG IG503 Plaster Mixing Procedures for specific soaking instructions.

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

Mechanically mixed slurries develop uniform casts with optimal strengths. USG Statuary Hydrocal
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 (see USG IG503
Plaster Mixing Procedures for details).

Longer mixing times result in higher mold strength and shorter set times.

POURING

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

Pouring a large amount of slurry directly on the face of the case mold may result in slight
densification of the USG Statuary Hydrocal Gypsum Cement mold at the point where it strikes the
surface of the case. This produces a hard spot, giving uneven absorption.

DRYING

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 drying efficiency because the air
pulled into the room is incapable of picking up much moisture from the molds.

The maximum temperature at which USG Statuary Hydrocal Gypsum Cement molds are safe from
calcination is 120 °F. With substantial free water in the mold, a higher drying temperature can
be used without difficulty. As drying progresses, the temperature must be reduced to prevent
calcination. Before removing molds from the dryer, the temperature should approach that of the
area around the dryer to prevent thermal shock.

STORAGE AND USE

When properly used, USG Statuary Hydrocal Gypsum Cement is safe to handle and easy to work
with. Keep indoors in a dry, stable environment. Do not stack more than two pallets high. Keep
from drafts. Rotate stock. Always follow handling and use directions and safety warnings on
the package.

TDS