PMC™-744

744x ⓘ D3288203-E6F8-1948-B8B3-024BFBCC0D4F
Polyurethane Elastomer

Two-component urethane rubber for flexible, durable molds and parts with superior tear and abrasion resistance. Shore A hardness 40.

  • Mix Ratio By Volume: 2A:1B
  • Mix Ratio By Weight: 2A:1B
  • Working time: 15 minutes
  • Cure Time: 16 hours
health-hazard.svg exclamation.svg

Warning

H302 - Harmful if swallowed.
H312 - Harmful in contact with skin.
H332 - Harmful if inhaled.
H315 - Causes skin irritation.
H319 - Causes serious eye irritation.
€ 267.63

(€ 221.18 without 21% VAT)

In stock

Description

This two-component urethane rubber cures at room temperature, designed for creating flexible, durable molds and parts. 

PMC™-744 features a Shore A hardness of 40, balancing toughness and flexibility. It is ideal for capturing fine surface details while offering superior tear and abrasion resistance.

  • Mix Ratio: By Volume 2A:1B
  • Mix Ratio By Weight: 2A:1B
  • Working time: 15 minutes
  • Cure Time: 16 hours
  • Shore Hardness: 44 A
  • Specific Gravity: 1.01 g/cc
  • Specific Volume: 0.9901 cm3/g
  • Color: Beige
  • Tensile Strength: 20.7 bar
  • 100% Modulus: 620.5 kPa
  • Elongation @ Break: 400 %
  • Die C Tear Strength: 15.8 kN/m
  • Shrinkage < .001 in. / in.
  • Mixed Viscosity: 3,400 cps

Instructions

Preparation

  • Store and use at room temperature (23°C). Keep environmental humidity low.
  • Ensure good ventilation. Use the product promptly due to limited shelf life.
  • Wear safety glasses, long sleeves, and rubber gloves to minimize contamination risk.

Sealing Materials

  • Porous materials (e.g., gypsum, concrete, wood) must be sealed before applying a release agent. Use SuperSeal™ or One Step™ sealers.
  • Shellac is suitable for sulfur or moisture-containing clays. Thermoplastics require sealing with shellac or PVA.
  • Non-porous surfaces (e.g., metal, glass) only need a release agent.

Applying a Release Agent

  • Use a mold-making release agent (e.g., Universal™ Mold Release). Apply liberally and brush with a soft brush for thorough coverage.
  • Let the release agent dry for 30 minutes.

Measuring & Mixing

  • Liquid urethanes are moisture-sensitive. Use clean metal, glass, or plastic tools and containers.
  • Pre-mix Part B before use. Mix two Parts A with one Part B for at least 3 minutes, scraping sides and bottom.
  • For large quantities (7 kg or more), use a mechanical mixer for 3 minutes, then hand mix for 1 minute.
  • Vacuum degassing can reduce air bubbles. Contact Smooth-On for more information.

Pouring

  • Pour the mixture at the lowest point of the containment field. Allow the rubber to flow over the model.
  • The liquid should level off at least 1.3 cm above the highest point of the model.

Curing

  • Allow curing for at least 16 hours at 23°C before demolding. Cure time can be reduced with mild heat or a cure accelerator.
  • Post-cure by heating to 65°C for 4-8 hours to enhance properties.

Using the Mold

  • Apply a release agent before each casting. The type depends on the material being cast.
  • For gypsum, sponge the mold with a soap solution for better flow and release.

Performance & Storage

  • Fully cured rubber is durable if used and stored properly. The physical life depends on usage conditions.

Specifications

Hundred Percent Modulus 90 psi
Color Beige
Mixed Viscocity 3,400 cps
Cure Time 16 hours
Pot Life 15 minutes
Specific Volume 27.5 cu. in./lb.
Die C Tear Strength 90 pli
Specific Gravity 1.01 g/cc
Mix Ratio By Weight 2A:1B
Shrinkage < .001 in. / in.
Mix Ratio By Volume 2A:1B
Tensile Strength 300 psi
Elongation At Break 400 %
Shore A Hardness 44
Available in Polyurethane Elastomer
Product Cure Time Shore A Hardness Specific Gravity Specific Volume Tensile Strength Shrinkage Die C Tear Strength Elongation At Break Hundred Percent Modulus Mixed Viscocity Mix Ratio By Volume Mix Ratio By Weight Pot Life Hundred Percent Modulus Color Mixed Viscocity Cure Time Pot Life Specific Volume Die C Tear Strength Specific Gravity Mix Ratio By Weight Shrinkage Mix Ratio By Volume Tensile Strength Elongation At Break Shore A Hardness Operating Temperature Range Mix Ratio Mixed Viscosity 100% Modulus Color - PMC™-746 Color - PMC™-746 Clear Amber Post Cure Temperature
PMC™-121 30/WET 16 h. 30 1.04 g/cc 26.7 cu. in./lb. 400 psi < .001 in. / in. 75 pli 1,000 % 82 psi 1,800 cps 1A:1B 1A:1B 30 min. 82 psi Clear Amber 1,800 cps 16 h. 30 min. 26.7 cu. in./lb. 75 pli 1.04 g/cc 1A:1B < .001 in. / in. 1A:1B 400 psi 1,000 % 30 - - - - - - -
PMC™-746 Amber Clear - - - - - - - - - - - - - - - - 16 h. at 73°F/23°C 15 min. at 73°F/23°C 26.9 cu. in./lb. 100 pli 1.03 g/cc - < .001 in./in. - 700 psi 650% 60 Above 65°F/18°C 2A:1B by weight or volume 1,200 cps 220 psi Ranges From Amber To Blue Clear Amber 150°F/65°C for 4 to 8 h.
PMC™-746 16 h. 60 1.03 g/cc 26.9 cu. in./lb. 700 psi < .001 in. / in. 100 pli 650 % 220 psi 1,200 cps 2A:1B 2A:1B 15 min. 220 psi Ranges From Amber To Blue 1,200 cps 16 h. 15 min. 26.9 cu. in./lb. 100 pli 1.03 g/cc 2A:1B < .001 in. / in. 2A:1B 700 psi 650 % 60 - - - - - - -
PMC™-121 30/DRY 16 h. 30 1.04 g/cc 26.7 cu. in./lb. 400 psi < .001 in. / in. 75 pli 1,000 % 82 psi 1,800 cps 1A:1B 1A:1B 30 min. 82 psi Clear Amber 1,800 cps 16 h. 30 min. 26.7 cu. in./lb. 75 pli 1.04 g/cc 1A:1B < .001 in. / in. 1A:1B 400 psi 1,000 % 30 - - - - - - -
PMC™-780 WET 48 h. 80 1.02 g/cc 27.2 cu. in./lb. 900 psi <.001 in. / in. 200 pli 750 % 400 psi 2,000 cps 2A:1B 2A:1B 25 min. 400 psi Light Amber 2,000 cps 48 h. 25 min. 27.2 cu. in./lb. 200 pli 1.02 g/cc 2A:1B <.001 in. / in. 2A:1B 900 psi 750 % 80 - - - - - - -
PMC™-780 DRY 48 h. 80 1.02 g/cc 27.2 cu. in./lb. 900 psi <.001 in. / in. 200 pli 750 % 400 psi 2,000 cps 2A:1B 2A:1B 25 min. 400 psi Light Amber 2,000 cps 48 h. 25 min. 27.2 cu. in./lb. 200 pli 1.02 g/cc 2A:1B <.001 in. / in. 2A:1B 900 psi 750 % 80 - - - - - - -
PMC™-790 48 h. 90 1.07 g/cc 25.9 cu. in./lb. 2,000 psi <.001 in. / in. 300 pli 550 % 640 psi 3,000 cps 2A:1B 2A:1B 20 min. 640 psi Clear Amber 3,000 cps 48 h. 20 min. 25.9 cu. in./lb. 300 pli 1.07 g/cc 2A:1B <.001 in. / in. 2A:1B 2,000 psi 550 % 90 - - - - - - -
PMC™-121 50/WET 16 h. 50 1.04 g/cc 26.7 cu. in./lb. 350 psi < .001 in. / in. 85 pli 500 % 82 psi 1,400 cps 1A:1B 1A:1B 30 min. 82 psi Clear Amber 1,400 cps 16 h. 30 min. 26.7 cu. in./lb. 85 pli 1.04 g/cc 1A:1B < .001 in. / in. 1A:1B 350 psi 500 % 50 - - - - - - -
PMC™-744 16 h. 44 1.01 g/cc 27.5 cu. in./lb. 300 psi < .001 in. / in. 90 pli 400 % 90 psi 3,400 cps 2A:1B 2A:1B 15 min. 90 psi Beige 3,400 cps 16 h. 15 min. 27.5 cu. in./lb. 90 pli 1.01 g/cc 2A:1B < .001 in. / in. 2A:1B 300 psi 400 % 44 - - - - - - -
PMC™-770 16 h. 70 1.04 g/cc 26.5 cu. in./lb. 750 psi <.001 in. / in. 200 pli 750 % 250 psi 3,000 cps - 2A:1B 30 min. 250 psi Light Amber 3,000 cps 16 h. 30 min. 26.5 cu. in./lb. 200 pli 1.04 g/cc 2A:1B <.001 in. / in. - 750 psi 750 % 70 - - - - - - -

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