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FAST
CAST Exterior Gypsum Cement |
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Click here for MSDS. |
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A High-Performance
Time Saving Solution for Your Exterior Casting Needs.
- Rapid setting cementitious
material when used with sand aggregate.
- Quick demolding
capability increases productivity 300% over conventional cements.
- Excellent resilience
and chip resistance.
- Ideal for free
standing, exterior casting, and decorative figurines.
- Grey in color.
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| Technical
Properties |
English |
Metric |
| Use
Consistency (parts of water by weight per 100 parts Fast Cast and
Sand) |
12.5 |
12.5 |
| 1
Hr. Compressive Strength |
2,500
psi |
17.2
MN/m2 |
| Dry
Compressive Strength |
8,000
psi |
55.2
MN/m2 |
| Maximum
Setting Expansion |
0.10% |
0.10% |
| Density |
| Wet
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131.0
lb/ft3 |
2.10
g/cm3 |
| Dry |
110.0
lb/ft3 |
1.76
g/cm3 |
| Set
Time* |
25-35
min. |
25-35
min. |
| *Other
set times may also be available. Call your sales representative for
more information. |
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General Directions and Guidelines
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Required
Mix Design |
50 lbs. Fast Cast
Exterior Gypsum Cement
50 lbs. sand
(fine aggregate)
1-1/2 gallons (U. S.) water (12.5 pounds) (Water measurement may have
to be adjusted slightly for particle size and water content of sand. Refer
to IG779 Technical Bulletin for details.)
Sand should be clean,
dry, pre-washed, and properly-sized. It should be free from dolomitic
and aluminum contamination and conform to ASTM C33 (see graph below).
An example of a suitable commercially available sand is All Purpose Sand.
Fast Cast Exterior Gypsum Cement must be used with sand to maximize durability.
For specific recommendations, consult your local United States Gypsum
Company Technical Sales Representative or call (800) 487-4431
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Mechanical
Mortar
Mix Procedures |
- With the mixer
operating, add half of the sand to the water.
- Carefully strew
or sift the Fast Cast Exterior Gypsum Cement into the mixer. Do not
soak.
- With the mixer
operating, carefully add the remainder of the sand.
- Mix thoroughly
until lump free and slurry becomes pourableÑ3 to 4 minutes, but no more
than 5 minutes.
- Carefully pour
the slurry into the mold to prevent entrapped air. Agitate the filled
mold to assist in removing any noticeable air bubbles.
- Set time is 25-35
minutes. Allow casts to remain in the mold for approximately one hour
after set to ensure the adequate green strength necessary for demolding.
- Demold and transfer
the cast to a suitable drying area. Bench dry the castings to a constant
weight before packaging for shipment. If the drying time must be accelerated,
castings can be placed in a drying room capable of producing both increased
air circulation and drying temperatures. Maximum temperature in a drying
room should not exceed 120°F. Consult your United States Gypsum
Company Technical Sales Representative for recommendations.
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Mechanical
Mixing - Variable
Speed Propeller Type Mixer |
- Add the sand to
the water.
- Carefully strew
or sift the Fast Cast Exterior Gypsum Cement into the mixing container.
Do not soak.
- Use a high-speed,
variable-drive propeller mixer to disperse the slurry. Mix for 3 to
4 minutes, but no more than 5 minutes.
- Mix thoroughly
until lump free and slurry becomes pourable - 3 to 4 minutes, but no
more than 5 minutes.
- Carefully pour
the slurry into the mold to prevent entrapped air. Agitate the filled
mold to assist in removing any noticeable air bubbles.
- Set time is 25-35
minutes. Allow casts to remain in the mold for approximately one hour
after set to ensure the adequate green strength necessary for demolding.
- Demold and transfer
the cast to a suitable drying area. Bench dry the castings to a constant
weight before packaging for shipment. If the drying time must be accelerated,
castings can be placed in a drying room capable of producing both increased
air circulation and drying temperatures.
Maximum temperature
in a drying room should not exceed 120°F. Consult your United States
Gypsum Company Technical Sales Representative for recommendations.
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Precautions
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- Water purity is
important. Water should be as pure as possible. Typically, if water
is drinkable, it is probably suitable for mixing the product. Water
contaminated with organic impurities, soluble salts, and other chemicals
may cause detrimental effects to Fast Cast Exterior Gypsum Cement.
- Proper mixing ensures
dispersion of the Fast Cast Exterior Gypsum Cement powder into the water.
Accurately weighed water, powder, and sand is necessary to assist in
fabrication of quality castings. Refer to required mix design for proper
amount of mixing water.
- Timing mix cycles
is essential. Mechanical mixing methods must be used. Do not mix by
hand.
- Pour pieces in
one continuous pour.
- Fast Cast Exterior
Gypsum Cement is not a suitable product for the fabrication of bird
baths, water fountains, or other applications where constant exposure
to water occurs; nor is it suitable for casting planters or flower potting
containers.
- Fast Cast Exterior
Gypsum Cement is not suitable for structural or non-structural exterior
architectural applications.
- Do not use Fast
Cast Exterior Gypsum Cement for below grade applications.
- Do not use sealers
or coatings on Fast Cast Exterior Gypsum Cement pieces.
- Do not use aggregate
that does not meet the size requirements of ASTM C33.
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