Premium Dry Condensation Silicone Rubber for Professional Concrete and Casting Resin Applications

The Silicone Condensation DC 3481 Fast is a two-component condensation-curing (RTV-2) mould rubber that cures at room temperature into a strong, dry silicone rubber. The set combines the DC 3481 A base with the fast 3081-F curing agent, mix ratio 100:5 by weight. With a Shore A hardness of 23, an off-white final colour and a working time of 30 to 45 minutes, the material is highly flowable and self-de-airing. Final mechanical properties are reached after 7 days. The rubber is ideally suited to the detailed reproduction of figures, ornaments and model-making, and to moulds for casting concrete, plaster, wax, soap and casting resins.

Key Benefits

• High tear strength – 24 kN/m: withstands repeated demoulding of complex replicas without tearing.
• High elongation at break – 543%: high elasticity makes releasing undercuts and complex shapes easy.
• Low linear shrinkage – 0.2 to 0.4%: dimensionally accurate castings that retain fine detail.
• Good tensile strength – 4.6 MPa: durable rubber that survives long production runs.
• Fast demould time – maximum 6 hours: shorter turnaround than the standard curing agent thanks to the 3081-F.
• Highly flowable – 22,100 mPa·s mixture: self-de-airing and easy to pour around fine details.

Typical Applications

• Moulds for concrete and concrete ornaments
• Castings in plaster and porcelain plaster
• Wax and candle production
• Soap casting
• Reproduction of figures and sculptures
• Model-making and industrial prototypes

Processing Instructions

1. Stir the A component thoroughly before use, as filler may settle during prolonged storage.
2. Weigh 100 parts A component and add 5 parts 3081-F curing agent (variation between 4% and 6% possible).
3. Mix the A and B components thoroughly by hand or mechanically until the curing agent is fully dispersed. Do not mix for an extended period and keep the temperature below 35°C.
4. De-air under vacuum if required; the mixture expands 3 to 5 times, so choose a large container. Excessive vacuum removes volatile components and may impair curing.
5. Pour the mixture onto the original within the working time, avoiding air entrapment.
6. Allow to cure for at least 6 hours at room temperature (22 to 24°C); final properties are reached after 7 days. A lower temperature lengthens the cure time, while higher temperature and humidity shorten the working time.

At 4% B component the material cures more slowly, giving air bubbles more time to escape. At 6% curing proceeds noticeably faster. Never mix more than you can process within the working time.

For a brush-on or spatula mould, add 0.6 to 2% (typically 1%) Thixo C. This thickens the mixture so it can be applied with a spatula; in that case provide the mould with a support shell of plaster bandage, modelling epoxy or acrylic resin with glass fabric.

Shelf Life

Stored cool, frost-free and in closed packaging, the shelf life is at least 1 year.

About the Manufacturer

Dow is a world market leader in the development and production of silicones for industrial and technical applications. The SILASTIC mould rubbers are known for their reliability and detail reproduction.

Professional Support

Unsure which curing agent, dosage or support-shell construction suits your application? Our specialists are happy to help. Contact us for personal advice on your mould or casting project.