Brand Silastic Application Type Mold-Making 1 Part or 2 Part 2 Part Material Form Liquid Substrate Polyurethane, Concrete, Porous Manufacturer Dow Chemistry Silicone rubber Application Method Spatula Cure Method Base/curing agent Cure Temperature (°C) 20 to 25, 23, 20 to 25 Cure Time (min) Fast, 1,440, 360 to 480 Viscosity (cPs) Low, Thixotropic, 9,000, Mixed, Non-flowable, Pourable Chemical Resistance Excellent High Temperature Resistance (°C) 200
Technical Data for Dow Silastic S-2 RTV Silicone Rubber
- Casting / Moldmaking - Mold-Making
1 Part or 2 Part
- 1 Part or 2 Part - 2 Part
- Part A Name - Base
- Part B Name - Curing Agent
- Silicone - Silicone rubber
- Spatula/Trowel - Spatula
- 2-Part Cure - Base/curing agent
Cure Temperature (°C) 20 to 25, 23, 20 to 25 Test Method Cure Time (min) Fast, 1,440, 360 to 480 Test Method Viscosity (cPs) Low, Thixotropic, 9,000, Mixed, Non-flowable, Pourable Test Method Linear Shrinkage (%) <0.10 Test Method Work / Pot Time (min) 60 Test Method Thixotropic Thixotropic Mix Ratio 10:1 (by volume), 100:10 (by weight)
General Bond Strength (psi) High Tear Strength (piw) 131 (ppi), 23 (kN/m), Tear Resistance Test Method Tensile Strength (psi) 913, 6.3 (Mpa) Test Method
Chemical Resistance Excellent High Temperature Resistance (°C) 200
Shore A Hardness 20, Medium Test Method Elongation (%) 6 Test Method Flexibility Flexible
Specific Gravity 1.130 Test Method Flash Point (°F) 145.4
Shelf Life Details When stored at or below 25°C (77°F) in the original unopened containers, SILASTIC S-2 RTV Base and SILASTIC S-2 RTV Curing Agent have a usable life of 12 months from the date of production., SILASTIC S-2 RTV Base and SILASTIC S-2 RTV Curing Agent can be sensitive to moisture and contamination. Ensure that containers are tightly closed after use. Shelf Life Type from the date of production Shelf Life (mon) 12
Not Good For
Don't Use For food molding, dental, human skin molding applications
Best Practices for Dow Silastic S-2 RTV Silicone Rubber
The surface of the original should be clean and free of loose material. If necessary, and in particular with porous substrates, use a suitable release agent such as petroleum jelly or soap solution.
In all cases, it is advisable to check before casting that no discoloration or adhesion occurs between the product and the original or mold frame.
Pour the mixed base and curing agent as soon as possible onto the original, avoiding air entrapment.
Weigh 100 parts of SILASTIC S-2 RTV Base and 10 parts of SILASTIC S-2 Curing Agent (see handling precautions) in a clean container, then mix together until the curing agent is completely dispersed in the base. Hand or mechanical mixing can be used, but do not mix for an extended period of time or allow the temperature to exceed 35°C (95°F). Mix sufficiently small quantities to ensure thorough mixing of the base and curing agent.
It is strongly recommended that entrapped air be removed in a vacuum chamber, allowing the mix to completely expand and then collapse. After a further 1-2 minutes under vacuum, the mix should be inspected and if free of air bubbles, can then be used. A volume increase of 2-3 times will occur on vacuum de-airing the mixture, so a suitably large container should be chosen.
Note: If no vacuum de-airing equipment is available, air entrapment can be minimised by mixing a small quantity of base and curing agent, then using a brush, painting the original with a 1-2mm layer. Leave at room temperature until the surface is bubble free and the layer has begun to cure. Mix a further quantity of base and curing agent and proceed as follows to produce a final mold. The base/curing agent ratio MUST be between 100:9.5 and 100:10.5.
The catalyzed material will cure to a flexible rubber within 6-8 hours at room temperature (22-24 or 71.6-75.2) and the mold can then be removed. If the working temperature is significantly lower, the cure time will be longer. Heat accelerating the cure is possible, but this will produce some apparent shrinkage of the mold, due to differences in volume contraction on cooling between the silicone rubber and the original. The higher the curing temperature, the greater the likely differences in dimensions.
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Cure Temperature Test Methods
|Cure Temperature||Cure Time Test Method|
|20 to 25°C|
|23°C||Cured for 24 hours at 23° C (73.4°F)|
|20 to 25°C|
Cure Time Test Methods
|Cure Time||Test Method|
|1,440 min||Cured for 24 hours at 23° C (73.4°F)|
|360 to 480 min|
Linear Shrinkage Test Methods
|Linear Shrinkage||Test Method||Temp|
|<0.10 %||Cured for 24 hours at 23°C (73.4°F)||23°C|
Viscosity Test Methods
|9,000 cPs||Mixture (100:10 by weight)|
Work / Pot Time Test Methods
|Work / Pot Time||Temperature|
Tear Strength Test Methods
|Tear Strength||Cure Time||Cure Temperature||Test Method|
|131 (ppi)||1,440 min||25°C||Die B|
|23 (kN/m)||1,440 min||25°C||Die B|
Tensile Strength Test Methods
|Tensile Strength||Cure Time||Cure Temperature|
|913 psi||1,440 min||25°C|
|6.3 (Mpa)||1,440 min||25°C|
Elongation Test Methods
|6 %||Cured for 24 hours at 23°C (73.4°F)|
Shore A Hardness Test Methods
|Shore A Hardness||Shore Hardness Test Method||Hardness Temperature|
|20||Cured for 24 hours at 23°C (73.4°F)||23°C|
Specific Gravity Test Methods
|Specific Gravity||Temperature||Test Method|
|1.130||25°C||Cured for 24 hours at 23°C (73.4°F)|