Knowde Enhanced TDS
Identification & Functionality
- Chemical Family
- Polymer Name
- Plastics & Elastomers Functions
- Technologies
- Product Families
Features & Benefits
- Materials Features
- Prodcut Highlights
These resins readily accept fillers (such as URE-FIL™ 3 from Smooth-On) and can be colored with SO-Strong™, UVO™ or Ignite™ color tints (Smooth-Cast™ 325 series accepts pigments better than the Smooth Cast™ 300 series). Fully cured castings are tough, durable, machinable and paintable. They resist moisture and mild solvents. Applications for Smooth-Cast™ 300 Series Liquid Plastics include reproducing small to medium size sculptures, making prototype models, special effect props and decorative jewelry.
Applications & Uses
- Markets
- Applications
- Plastics & Elastomers End Uses
- Plastics & Elastomers Processing Methods
- Processing Recommendations
Preparation
These products have a limited shelf life and should be used as soon as possible. Materials should be stored and used in a warm environment (73°F/23°C). All liquid urethanes will react with moisture in the air, causing bubbles. Use in a low humidity environment (below 50% RH). Mixing containers should have straight sides and a flat bottom. Mixing sticks should be flat and stiff with defined edges for scraping the sides and bottom of your mixing container. Because no two applications are quite the same, a small test application to determine suitability for your project is recommended if performance of this material is in question.
Applying a Release Agent
A release agent is necessary to facilitate demolding when casting into or over most surfaces. Use a release agent made specifically for mold making (Universal™ Mold Release or Mann’s Ease Release™ 200 available from Smooth-On or your Smooth-On distributor). A liberal coat of release agent should be applied onto all surfaces that will contact the plastic.
IMPORTANT
To ensure thorough coverage, apply release and brush with a soft brush over all surfaces. Follow with a light mist coating and let the release agent dry for 30 minutes. Smooth-On silicone rubber molds usually do not require a release agent unless casting silicone into the mold. Applying a release agent will prolong the life of the mold.
Properties
- Typical Properties
| Value | Units | Test Method / Conditions | |
| Pot Life at 73°F (23°C) | 15-20 | Minute | ASTM D-2471 |
| Cure Time at 73°F (23°C) | 3-4 | Hr | — |
| Tensile Strength | 3000 | psi | ASTM D-638 |
| Tensile Modulus | 134000 | psi | ASTM D-638 |
| Elongation at Break | 7.5 | % | ASTM D-638 |
| Flexural Strength | 4000 | psi | ASTM D-790 |
| Flexural Modulus | 118000 | psi | ASTM D-790 |
| Compressive Strength | 3800 | psi | ASTM D-695 |
| Compressive Modulus | 44900 | psi | ASTM D-695 |
| Shrinkage | 0.0065 | in./in. | ASTM D-2566 |
| Mix Ratio | 1A:1B (100A:90B) | by volume (by weight) | — |
| Mixed Viscosity | 80 | cps | ASTM D-2393 |
| Specific Gravity | 1.05 | g/cc | ASTM D-1475 |
| Specific Volume | 26.4 | cu. in./lb. | ASTM D-1475 |
| Hardness | 70 | Shore D | ASTM D-2240 |
| Heat Deflection Temp | 120 (50) | °F (°C) | ASTM D-648 |
Technical Details & Test Data
- Measuring and Mixing
Liquid urethanes are moisture sensitive and will absorb atmospheric moisture. Mixing tools and containers should be clean and made of metal, glass or plastic. Materials should be stored and used in a warm environment (73°F/23°C). Stir or shake both Part A & Part B thoroughly before dispensing. After dispensing equal amounts of Parts A and B into mixing container (100A:90B by weight), mix thoroughly. Scrape the sides and bottom of your container several times. Be careful not to splash low viscosity material out of the container.
- Curing and Performance
Pouring
Pour your mixture in a single spot at the lowest point of the containment field and let the mixture seek its level. This will help minimize air entrapment. For Best Results . . . Best results are obtained using a pressure casting technique. After pouring the mixed compound, the entire casting assembly (mold, dam structure, etc.) is placed in a pressure chamber and subjected to 60 PSI (4.2 kg/cm2 ) air pressure for the full cure time of the material.
Curing - Important
Use this product with at least room size ventilation or in proximity to a forced outlet air vent and do not inhale/breathe fumes. Fumes, which may be visible with a significant mass concentration, will quickly dissipate with adequate ventilation. Castings with significant mass may be hot to the touch and irritate skin immediately following cure. Let casting cool to room temperature before handling. Demold time of the finished casting depends on mass and mold configuration. Low mass or thin-walled castings will take longer to cure than castings with higher mass concentration. Smooth-Cast™ 300 will cure in 7 - 10 minutes (Smooth-Cast™ 305 in 30 – 40 minutes and Smooth-Cast™ 310 in 2 - 4 hours) depending on mass and mold configuration.
Post Cure
Castings will reach “full cure” faster and achieve maximum physical properties if post cured. Allow material to cure for recommended Cure Time at room temperature followed by 4 - 6 hours at 150°F/65°C. Allow casting to come to room temperature before handling.
Performance
Cured castings are rigid and durable. They resist moisture, moderate heat, solvents, dilute acids and can be machined, primed/painted or bonded to other surfaces (any release agent must be removed). If machining cured material, wear dust mask or other apparatus to prevent inhalation of residual particles. Castings can be displayed outdoors after priming and painting. Unpainted castings will yellow over time - more quickly when exposed to ultra-violet light.
Safety & Health
- Safety
Wear safety glasses, long sleeves and rubber gloves to minimize contamination risk. Use only in a well-ventilated area.
Storage & Handling
- Shelf Life
Shelf life of product is reduced after opening. Remaining product should be used as soon as possible. Immediately replacing the lids on both containers after dispensing product will help prolong the shelf life of the unused product. XTEND-IT™ Dry Gas Blanket (available from Smooth-On) will significantly prolong the shelf life of unused liquid urethane products.