Description
This silicone is a very soft, platinum-cured material that is clearer than other silicones.
Ecoflex™ 00-31 Near Clear™ is easy to use, mixed in a 1A:1B ratio by weight or volume, and cures at room temperature with negligible shrinkage.
The low viscosity ensures easy mixing and de-airing. The cured material is skin safe and certified by an independent laboratory.
Features
- Cured rubber is very soft, strong, and stretchy, stretching many times its original size without tearing and will rebound to its original form without distortion.
- Can be color pigmented with Silc Pig™ pigments for creating a variety of color effects.
- Silicone Thinner™ can be added to further lower the viscosity.
- For a slightly harder silicone, a different version is available.
Technical Properties
- Mix Ratio By Volume: 1A:1B
- Pot Life: 40 minutes
- Cure Time: 4 hours
- Shore Hardness: 00-31
- Specific Gravity: 1.07 g/cc
- Specific Volume: 0.93 cm³/g
- Color: Water Clear Translucent
- Tensile Strength: 1.38 MPa
- 100% Modulus: 69 kPa
- Elongation @ Break: 900%
- Die B Tear Strength: 6.7 kN/m
- Useful Temperature Range: -54°C to 232°C
- Mixed Viscosity: 3,000 cps
Instructions
Safety
Use in a properly ventilated area. Wear safety glasses, long sleeves, and rubber gloves to minimize contamination risk. Wear vinyl gloves only. Latex gloves will inhibit the cure of the rubber. Store and use material at room temperature (23°C/73°F). Warmer temperatures will drastically reduce working time and cure time. Storing material at warmer temperatures will also reduce the usable shelf life of unused material. These products have a limited shelf life and should be used as soon as possible.
Cure Inhibition
Addition-cure silicone rubber may be inhibited by certain contaminants in or on the pattern to be molded resulting in tackiness at the pattern interface or a total lack of cure throughout the mold. Latex, tin-cure silicone, sulfur clays, certain wood surfaces, newly cast polyester, epoxy, tin cure silicone rubber or urethane rubber may cause inhibition. If compatibility between the rubber and the surface is a concern, a small-scale test is recommended. Apply a small amount of rubber onto a non-critical area of the pattern. Inhibition has occurred if the rubber is gummy or uncured after the recommended cure time has passed.
To prevent inhibition, one or more coatings of a clear acrylic lacquer applied to the model surface is usually effective. Allow any sealer to thoroughly dry before applying rubber. Note: Even with a sealer, platinum silicones will not work with modeling clays containing heavy amounts of sulfur. Do a small scale test for compatibility before using on your project.
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.
Note: Even with a sealer, platinum silicones will not work with modeling clays containing heavy amounts of sulfur. Do a small scale test for compatibility before using on your project.
Applying A Release Agent
Although not usually necessary, a release agent will make demolding easier when pouring into or over most surfaces. Ease Release™ 200 is a proven release agent for use with silicone rubber. Mann Ease Release™ products are available from Smooth-On or your Smooth-On distributor.
IMPORTANT: To ensure thorough coverage, lightly brush the release agent with a soft brush over all surfaces of the model. Follow with a light mist coating and let the release agent dry for 30 minutes.
If there is any question about the effectiveness of a sealer/release agent combination, a small-scale test should be made on an identical surface for trial.
Measuring & Mixing
Before you begin, pre-mix Part B thoroughly. After dispensing required amounts of Parts A and B into mixing container (1A:1B by volume or weight), mix thoroughly for 3 minutes making sure that you scrape the sides and bottom of the mixing container several times. After mixing parts A and B, vacuum degassing is recommended to eliminate any entrapped air. Vacuum material for 2-3 minutes (29 inches of mercury), making sure that you leave enough room in container for product volume expansion.
Pouring, Curing & Mold Performance
For best results, pour your mixture in a single spot at the lowest point of the containment field. Let the rubber seek its level up and over the model. A uniform flow will help minimize entrapped air. The liquid rubber should level off at least 1.3 cm (1/2”) over the highest point of the model surface.
Curing / Post Curing - Allow rubber to cure as prescribed at room temperature (23°C/73°F) before demolding. Do not cure rubber where temperature is less than 18°C (65°F). Time to demold can be reduced with mild heat. IMPORTANT: Rubber will darken considerably when exposed to heat. Note: Allow mold to cool to room temperature before handling.
Optional: Post curing the mold will aid in quickly attaining maximum physical and performance properties. After curing at room temperature, expose the rubber to 80°C (176°F) for 2 hours and 100°C (212°F) for one hour. Allow mold to cool to room temperature before using. IMPORTANT: Rubber will darken considerably when exposed to heat.
If Using As A Mold - When first cast, silicone rubber molds exhibit natural release characteristics. Depending on what is being cast into the mold, mold lubricity may be depleted over time and parts will begin to stick. No release agent is necessary when casting wax or gypsum. Applying a release agent such as Ease Release™ 200 (available from Smooth-On) prior to casting polyurethane, polyester and epoxy resins is recommended to prevent mold degradation.
Thinning Silicone
Smooth-On’s Silicone Thinner™ will lower the viscosity of the silicone for easier pouring and vacuum degassing. A disadvantage is that ultimate tear and tensile are reduced in proportion to the amount of Silicone Thinner™ added. It is not recommended to exceed 10% by weight of total system (A+B). See the Silicone Thinner™ technical bulletin (available from Smooth-On or your Smooth-On distributor) for full details.
Mold Performance & Storage
The physical life of the mold depends on how you use it (materials cast, frequency, etc.). Casting abrasive materials such as concrete can quickly erode mold detail, while casting non-abrasive materials (wax) will not affect mold detail. Before storing, the mold should be cleaned with a soap solution and wiped fully dry. Two part (or more) molds should be assembled. Molds should be stored on a level surface in a cool, dry environment.
