Description
This platinum silicone rubber is easy to use, mixed in a 1A:1B ratio by volume, eliminating the need for a weighing scale. It features a low viscosity, which means vacuum degassing is not required for most applications. This fast-curing material has a pot life of 6 minutes and a cure time of 30 minutes.
Features
- Cures to a soft, strong rubber that is tear-resistant and exhibits very low long-term shrinkage.
- Durable molds suitable for casting wax, gypsum, resins, and other materials.
- Heat resistant up to 232°C (450°F), suitable for casting low-temperature melt metal alloys.
- Not intended for brush-on moldmaking.
Technical Properties
- Mix Ratio By Volume: 1A:1B
- Mix Ratio By Weight: 1A:1B
- Pot Life: 6 minutes
- Cure Time: 30 minutes
- Shore Hardness: 16 A
- Specific Gravity: 1.18 g/cc
- Specific Volume: 0.85 cm³/g
- Tensile Strength: 2.76 MPa (400 psi)
- 100% Modulus: 379 kPa (55 psi)
- Elongation @ Break: 440%
- Die B Tear Strength: 15.4 kN/m (88 pli)
- Color: Blue-Green
- Useful Temperature Range: -54°C to 232°C (-65°F to 450°F)
Use Cases
Ideal for creating molds for casting wax, gypsum, resins, and low-temperature melt metal alloys. Also used in applications such as making molds for concrete planters, face shields, forensic impression molds, and more.
Instructions
Safety
Use in a properly ventilated area. Wear safety glasses, long sleeves, and rubber gloves to minimize contamination risk. Use vinyl gloves only, as latex gloves will inhibit the cure of the rubber. Store and use material at room temperature (23°C/73°F). Warmer temperatures will reduce working and cure time and also reduce the shelf life of unused material.
Cure Inhibition
Addition cured silicone rubber may be inhibited by certain contaminants, resulting in tackiness or lack of cure. Latex, sulfur clays, certain wood surfaces, newly cast polyester, epoxy, or urethane rubber may cause inhibition. A small-scale test is recommended to check compatibility. Apply a small amount of rubber onto a non-critical area of the pattern. If inhibition occurs, the rubber will be gummy or uncured. Applying a clear acrylic lacquer to the model surface can prevent inhibition. Allow the sealer to dry thoroughly before applying rubber.
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 like Ease Release™ 200 can make demolding easier. Mann Ease Release™ products are available from distributors.
Measuring & Mixing
Pre-mix Part A and Part B separately. Dispense required amounts of Parts A and B into a mixing container (1A:1B by volume) and mix thoroughly, scraping the sides and bottom of the container. The rubber should be a uniform color with no streaks.
Optional Vacuum Degassing
Vacuum degassing helps eliminate entrapped air. After mixing parts A and B, vacuum material for 2-3 minutes at 29 inches of mercury, ensuring enough room in the container for expansion.
Pouring
Pour the mixture in a single spot at the lowest point of the containment field. Let the rubber seek its own level. 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
Allow silicone rubber to cure for 30 minutes at room temperature (23°C/73°F) before demolding.
Heat Curing
Time to demold can be reduced by applying mild heat. Example: After pouring, place the mold in a hot box or industrial oven at 60°C (140°F) to reduce demold time of a 1.3 cm (1/2”) thick section to about 10 minutes. Time will vary depending on mold thickness. Adding Plat-Cat™ cure accelerator will also reduce demold time. Pot life and cure times can be extended using Slo-Jo™ cure retarder. Do not cure rubber where temperature is less than 18°C (65°F).
Mold Performance & Storage
The physical life of the mold depends on usage. Casting abrasive materials can erode mold detail, while non-abrasive materials (wax) will not. Before storing, clean the mold with a soap solution and dry fully. Assemble two-part molds and store on a level surface in a cool, dry environment.
