Platinum Silicone Rubber Compounds, 2x5Kg Addition Cure, SI-40A-60M
- All Composites,
- Addition Cure Silicone Rubber Compounds.
- silicone rubber suitable for the production of silicone moulds and silicone mouldings/components. Unpigmented silicone and catalyst
Mixed Viscosity at 23 °C, approx : 9000 cps +/- 1000 cps
Density at 23 °C, approx: 1.10
Gel time: 60 minutes +/-10 minutes
Cure time: 12 hrs
Mix ratio: 1:1 by weight
Hardness: 40 shore A +/- 2
Tensile strength : 60 N/mm 2 ± 10
Elongation : 450% ±50
Tear strength: 12 N/mm ±2
TECHNICAL OVERVIEW PROCESSING RECOMMENDATIONS
Platinum Silicones cure at room temperature with negligible shrinkage. These silicones exhibit good chemical,
abrasion and heat resistance. Materials such as plasters, concrete, wax, low-melt metal alloys or resins (urethane,
epoxy or polyester) can then be cast into these silicone rubbers without a release agent. The surfaces with which
the material comes in contact must be perfectly clean, free of grease and dry. Close the bottles after use so as not
to confuse the cover of the catalyst with that of the base when re-sealing. Be aware of possible cross-
contamination. It’s highly recommended to use only dedicated gear when processing poly-addition RTV silicone
rubber (including degassing devices).
Use in a properly ventilated area (“room size” ventilation). Wear safety glasses, long sleeves and nitrile gloves to
minimize contamination risk. Latex gloves will inhibit the cure of the rubber.
Store and use material at room temperature (73°F/23°C). 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 Be aware that contact with certain material can inhibit the curing of the silicone rubber. 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
Common contaminants to be avoided include:
-Natural or synthetic rubber, vulcanized with sulphur derivatives.
-Poly-condensation RTV catalyzed with metallic salts.
-PVC stabilizing agents.
-Amine cured epoxies.
-Sulphur, tin and amines derivatives.
-In case of doubt, carry out a small test by pouring the mixture onto a small area of the object.
Latex, tin-cure silicone, sulfur clays, certain wood surfaces, newly cast polyester, epoxy or urethane rubber my
cause inhibition. If compatibility between the rubber and the surface is a concern, a small-scale test is
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.
Apply a small amount of rubber onto a non-critical area of the pattern. Inhibition has occurred if the silicone s
gummy or uncured after the recommended cure time has passed.
The Material Safety Data Sheet (MSDS) for this product should be read prior to use and is available upon request.
Allcomposites products are safe to use if directions are read and followed carefully.
Keep Out of Reach of Children
Be careful. Use only with adequate ventilation. Contact with skin and eyes may cause irritation. Flush eyes with water for 15
minutes and seek immediate medical attention. Remove from skin with waterless hand cleaner followed by soap and water.
Important: The information contained in this bulletin is considered accurate. However, no warranty is expressed or implied
regarding the accuracy of the data, the results to be obtained from the use thereof, or that any such use will not infringe upon
a patent. User shall determine the suitability of the product for the intended application and assume all risk and liability
whatsoever in connection therewith.
Applying A Release Agent - Although not usually necessary, a release agent will make demolding easier when pouring into or
over most surfaces. Test you mold release prior using it on your pattern. 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.
IMPORTANT: Release agent must be let to dry for 30 minutes.
MEASURING & MIXING
Stir Part A and shake Part B thoroughly before dispensing. Using a gram scale, dispense required amounts of parts A and B
into a mixing container and mix for 3 minutes. Scrape the sides and bottom of the container several times. 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. After mixing parts A and B, vacuum degassing is recommended to eliminate any entrapped
air in liquid rubber. Your vacuum pump must pull a minimum of 29 inches of mercury (or 1 Bar / 100 KPa). Leave enough room
in container for material expansion. Vacuum material until it rises, breaks and falls. Vacuum for 5 minutes after material falls.
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 1/2” (1.3 cm)
over the highest point of the model surface.
Curing / Post Curing Allow rubber to cure as prescribed at room temperature
(73°F/23°C) before demolding. Do not cure rubber where temperature is less than 65°F/18°C. Optional: Post curing the mold
will aid in quickly attaining maximum physical and performance properties. After curing at room temperature, expose the
rubber to 176°F/80°C for 2 hours and 212°F/100°C for one hour. Allow mold to cool to room temperature before using.
Using The 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.
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.