Premium Pourable Condensation Silicone for Professional Mold Making and Casting Resin Reproduction Applications

The Elastosil® M 4440 is a pourable, condensation-curing (RTV-2) two-component silicone rubber that cures at room temperature to a final white color with a Shore A hardness of approximately 37. This kit includes the matching hardener Catalyst T 37, which provides a long processing time of approximately 80 minutes and a curing time of approximately 10 hours. Thanks to its very good flowability and self-deaeration, the material effortlessly fills even fine details, while its excellent resistance to polyester and polyurethane resins ensures a long mold life. With a mixing ratio of 3% T37 by weight, this is a reliable all-round molding rubber for cost-effectively producing molds.

Key Benefits

• Shore A hardness 37 – firm yet flexible mold with good dimensional stability and easy demolding.
• Mixing viscosity 20,000 mPa·s – very good flowability and self-deaeration, fills fine surface details without air entrapment.
• Tear strength 4.5 N/mm – excellent resistance to tearing, even with repeated demolding.
• Elongation at break 220% – high flexibility for demolding models with slight undercuts.
• Linear shrinkage 0.4% – limited shrinkage for dimensionally accurate reproductions.
• Pot life 80 minutes with T37 – ample processing time for larger or complex molds.

Typical Applications

• Production molds for casting polyester and polyurethane resins.
• Reproduction of ornaments, statues, and decorative elements.
• Molds for plaster, concrete, and artificial stone.
• Wax and candle molds for artisanal and industrial applications.
• Prototyping and small-series production where dimensional stability is required.

Processing Instructions

1. Before use, carefully stir the A-component (silicone base) in its packaging to evenly distribute any settled fillers.
2. Weigh the Catalyst T 37 (B-component) by weight: 3% of the A-component amount (3 grams of T37 per 100 grams of silicone).
3. Mix both components slowly and thoroughly, scraping the sides and bottom of the mixing container until a homogeneous mixture is formed.
4. Preferably deaerate the mixture under vacuum (10–20 mbar) to prevent air entrapment.
5. Pour the mixture into the mold in a thin stream from a low height within the pot life of approximately 80 minutes.
6. Allow the silicone to cure for approximately 10 hours at room temperature (23 °C). Higher humidity and a higher dosing ratio will shorten the processing and curing times.

Wacker Chemie AG is a world market leader in the development and production of silicones for industrial and technical applications.

Professional Support

Are you unsure if Elastosil® M 4440 is the right choice for your mold or reproduction material? Our specialists are happy to advise you on hardness, resin resistance, and the desired number of casts. Feel free to contact us for personalized advice.