Smooth Cast 300

SKU: 796000

Size: Pint Kit
Sale price$36.16

unit(s) in Stock.


unit(s) in Stock.


unit(s) in Stock.

*Price and availability may vary.


Unit Size Net Weight
Pint Kit 1.9 lb
Gallon Kit 15.4 lb
Five Gallon Kit 77 lb



Smooth-Cast 300 is a urethane casting resin which has an ultra-low viscosity and yields castings that are bright white and virtually bubble free.
Technical Properties
Mix Ratio by Weight 100A:90B
Mix Ratio by Volume 1A:1B
Pot Life 3 minutes
Cure Time 10 minutes
Color Whihte
Shore Hardness 70D
Mixed Viscosity 80 cps
Shrinkage 0.01 in./in.
Specific Volume 26.4 cu. in./lb.
Specific Gravity 1.05g/cc
Tensile Strength 3,000 psi
Elongation @ Break 5%
Compressive Modulus 45,800 psi
Tensile Modulus 139,500 psi
Flexural Strength 4,510 psi
Flexural Modulus 128,000 psi
Compressive Strength 4,000 psi
Heat Deflection Temp 120¼F


Smooth-Cast 300 Series liquid plastics are ultra-low viscosity casting resins yielding castings that are bright white and virtually bubble free. Vacuum degassing is not necessary. They offer the convenience of a one to one mix ratio (one part A to one part B by volume). The differences between them are pot life and demold time.
These resins readily accept fillers (such as URE-FIL 3 from Smooth-On) and can be pigmented (SC325 Series will achieve true color representation better than the SC300 series). Fully cured castings are tough, durable, machinable and paintable. They resist moisture and mild solvents.
Applications for Smooth-Cast Liquid Plastics include reproducing small to medium size sculptures, cold cast bronze castings, making prototype models, special effect props and decorative jewelry. Those interested in making roto cast pieces should refer to the Smooth-Cast ROTO technical bulletin.
How do I remove release agent from my cured urethane casting if I want to prime or paint the casting?
Removing a silicone-based release agent from your cured urethane casting is not easy. The most effective way is to sand blast or bead blast the surface of your casting. However, sand blasting removes a micro thin layer of the casting's surface. If not done properly, you can damage or remove fine detail. Soap Wipe or brush the casting with a soap that has high alkali content. Cascade brand dishwashing gel is highly alkaline and also contains baking soda, which is an advantage. Solvents Wipe or brush the casting with Acetone, Toluene, Isopropyl Alcohol or Mineral Spirits.
Important: follow all safety precautions when using flammable liquids. You can then prime and paint your casting.
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