Smooth-Cast™ 300Q

cast300Qx 709A3B0C-82C0-744E-9D71-93F5CB7981DF
Polyurethane Resin

Fast-setting, ultra-low-viscosity casting resin with bright white finish and an easy 1:1 mixing ratio for virtually bubble-free castings. Ultra-fast curing, minimal pot-life.

  • Shore Hardness: 70D
  • Working time: 30-seconds
  • Demold time: 5 min 
  • Elongation at Break: 5%
  • 1:1 mix ratio by volume
€ 153.91

(€ 127.20 without 21% VAT)

In stock

Description

This fast-setting, ultra-low viscosity casting resin produces bright white, nearly bubble-free castings. 

Smooth-Cast™ 300Q does not require vacuum degassing and features a 1A:1B mix ratio by volume or 100A:90B by weight.

The Smooth-Cast™ 300 Series of liquid plastics are ultra-low viscosity casting resins that yield castings that are bright white and virtually bubble free. Vacuum degassing is not necessary. They offer the convenience of a 1A:1B by volume or 100A:90B by weight mix ratio. 

The differences between them are pot life and demold time.

Key Features

  • Shore Hardness: 70D
  • Elongation at Break: 5%
  • Working time: 30-seconds
  • Easy to measure and mix
  • Low viscosity for excellent detail capture
  • Cures to a bright white finish

The resin can be filled with materials like URE-FIL™ 3 and colored with SO-Strong™ or Ignite™ tints. Fully cured castings are tough, durable, machinable, and paintable, with resistance to moisture and mild solvents.

Applications

  • Reproducing small to medium sculptures
  • Casting into alginate molds
  • Creating prototype models
  • Making special effect props and decorative jewelry

Instructions

Safety:

  • Store and use materials in a warm environment (23°C).
  • Use products promptly due to limited shelf life.
  • All liquid urethanes are moisture-sensitive; use clean metal, glass, or plastic tools and containers.
  • Work in a well-ventilated area and wear safety glasses, long sleeves, and rubber gloves.
  • Conduct a small test application to ensure material suitability for your project.

Applying a Release Agent:

  • Use a mold-specific release agent like Universal™ Mold Release or Mann’s Ease Release™ 200.
  • Apply liberally to all surfaces contacting the plastic.
  • Brush with a soft brush for thorough coverage, then mist and let dry for 30 minutes.
  • Smooth-On silicone molds may not need a release agent unless casting silicone.

Measuring & Mixing:

  • Ensure tools and containers are clean and dry.
  • Stir or shake Parts A and B thoroughly before dispensing.
  • Mix equal amounts by volume or 100A:90B by weight, scraping sides and bottom of the container.

Pouring, Curing & Performance:

  • Pour mixture at the lowest point to minimize air entrapment.
  • For best results, use pressure casting at 0.42 MPa during curing.
  • Ensure adequate ventilation to dissipate fumes during curing.
  • Allow castings to cool to room temperature before handling.
  • Post-cure at 65°C for 4-6 hours to enhance properties.
  • Cured castings are rigid, durable, and resistant to moisture and mild solvents.
  • Unpainted castings may yellow over time with UV exposure.

Specifications

Color White
Mixed Viscocity 80 cps
Cure Time 5 minutes
Pot Life 30 seconds
Flexural Strength 4,510 psi
Flexural Modulus 128,000 psi
Specific Volume 26.4 cu. in./lb.
Specific Gravity 1.05 g/cc
Mix Ratio By Weight 100A:90B
Shrinkage 0.01 in. / in.
Mix Ratio By Volume 1A:1B
Tensile Strength 3,000 psi
Elongation At Break 5 %
Shore D Hardness 70
Heat Deflection Temp 120 °F
Compressive Strength 4,000 psi
Tensile Modulus 139,500 psi
Compressive Modulus 45,800 psi
Available in Polyurethane Resin
Product Cure Time Specific Gravity Specific Volume Tensile Strength Tensile Modulus Compressive Strength Compressive Modulus Flexural Strength Shrinkage Heat Deflection Temp Elongation At Break Flexural Modulus Mixed Viscocity Mix Ratio By Volume Mix Ratio By Weight Pot Life Shore D Hardness Color Mixed Viscocity Cure Time Pot Life Flexural Strength Flexural Modulus Specific Volume Specific Gravity Mix Ratio By Weight Shrinkage Mix Ratio By Volume Tensile Strength Elongation At Break Shore D Hardness Heat Deflection Temp Compressive Strength Tensile Modulus Compressive Modulus
Smooth-Cast™ 300Q 5 min. 1.05 g/cc 26.4 cu. in./lb. 3,000 psi 139,500 psi 4,000 psi 45,800 psi 4,510 psi 0.01 in. / in. 120 °F 5 % 128,000 psi 80 cps 1A:1B 100A:90B 30 sec. 70 White 80 cps 5 min. 30 sec. 4,510 psi 128,000 psi 26.4 cu. in./lb. 1.05 g/cc 100A:90B 0.01 in. / in. 1A:1B 3,000 psi 5 % 70 120 °F 4,000 psi 139,500 psi 45,800 psi
Smooth-Cast™ 300 10 min. 1.05 g/cc 26.4 cu. in./lb. 3,000 psi 139,500 psi 4,000 psi 45,800 psi 4,510 psi 0.01 in. / in. 120 °F 5 % 128,000 psi 80 cps 1A:1B 100A:90B 3 min. 70 White 80 cps 10 min. 3 min. 4,510 psi 128,000 psi 26.4 cu. in./lb. 1.05 g/cc 100A:90B 0.01 in. / in. 1A:1B 3,000 psi 5 % 70 120 °F 4,000 psi 139,500 psi 45,800 psi
Smooth-Cast™ 305 30 min. 1.05 g/cc 26.4 cu. in./lb. 3,000 psi 134,000 psi 3,800 psi 44,900 psi 4,000 psi 0.0065 in. / in. 120 °F 7.5 % 118,000 psi 80 cps 1A:1B 100A:90B 7 min. 70 White 80 cps 30 min. 7 min. 4,000 psi 118,000 psi 26.4 cu. in./lb. 1.05 g/cc 100A:90B 0.0065 in. / in. 1A:1B 3,000 psi 7.5 % 70 120 °F 3,800 psi 134,000 psi 44,900 psi
Smooth-Cast™ 310 4 h. 1.05 g/cc 26.4 cu. in./lb. 3,000 psi 134,000 psi 3,800 psi 44,900 psi 4,000 psi 0.0065 in. / in. 120 °F 7.5 % 118,000 psi 80 cps 1A:1B 100A:90B 20 min. 70 White 80 cps 4 h. 20 min. 4,000 psi 118,000 psi 26.4 cu. in./lb. 1.05 g/cc 100A:90B 0.0065 in. / in. 1A:1B 3,000 psi 7.5 % 70 120 °F 3,800 psi 134,000 psi 44,900 psi
Smooth-Cast™ 385 2 h. 1.60 g/cc 17.3 cu. in./lb. 3,100 psi 400,000 psi 8,500 psi 400,000 psi 5,900 psi 0.0006 in. / in. 135 °F 1 % 433,000 psi 3,000 cps - 1A:5B 20 min. 85 Beige 3,000 cps 2 h. 20 min. 5,900 psi 433,000 psi 17.3 cu. in./lb. 1.60 g/cc 1A:5B 0.0006 in. / in. - 3,100 psi 1 % 85 135 °F 8,500 psi 400,000 psi 400,000 psi

Why buy at FormX?

Subscribe to our Newsletter

Receive €5,- discount on your first purchase!

Visa logo iDeal logo Mastercard logo Paypal logo FedEx logo FedEx logo
This website has been developed by Usecue B.V.
© 2026 FormX B.V.