Premium pourable condensation-curing silicone rubber for professional mold and reproduction applications

This kit contains the complete two-component combination of Elastosil M 4514 (component A) with its corresponding hardener Catalyst T 51 (component B). It is a pourable, condensation-curing (tin-cure) RTV-2 silicone rubber that vulcanizes at room temperature into a white, flexible mold with a Shore A hardness of approximately 25. The combination with T 51 is specifically intended for casting polyester resins, plaster, concrete, artificial stone, wax, and low-melting metal alloys, and thanks to its excellent resin resistance, offers a greatly extended mold lifespan. Mixed in a 100:5 weight ratio (A:B), the mixture has a viscosity of approximately 25,000 mPa·s, a pot life of 60 to 90 minutes, and a demolding time of 8 to 10 hours at 23 °C and 50% relative humidity.

Key Benefits

• Shore A hardness 25 – flexible mold that allows for easy and damage-free demolding even with deep undercuts.
• Tear strength > 25 N/mm – very high tear and puncture resistance for long service life with repeated use.
• Tensile strength 4.5 N/mm² and elongation 450% – high elasticity, allowing the mold to be stretched significantly without damage.
• Linear shrinkage < 0.4% – precise dimensional stability for true-to-detail reproductions.
• Mixture viscosity 25,000 mPa·s – very good flowability and self-deaeration for bubble-free castings.
• Excellent resin resistance (polyester and polyurethane) – high number of copies per mold, even with aggressive casting resins.

Typical Applications

• Molds for casting polyester resins and polyurethane resins.
• Reproduction of sculptures, ornaments, and restoration objects with significant undercuts.
• Molds for plaster, concrete, and artificial stone, e.g., facade elements and tiles.
• Molds for wax, candles, and the lost wax casting process.
• Molds for low-melting metal alloys.
• Solid and skin molds, single or multi-piece, using casting, impression, or brushing techniques.

Processing Instructions

1. Stir component A (Elastosil M 4514) thoroughly in its container before use to distribute any settling.
2. Weigh the components in a 100:5 weight ratio, i.e., 5 grams of T 51 to 100 grams of component A. Less hardener extends pot life and demolding time; more hardener accelerates curing but increases shrinkage and aging. Never use too little hardener, otherwise the silicone will not cure (properly).
3. Mix A and B carefully and evenly, scraping the walls and bottom of the mixing container thoroughly.
4. Preferably deaerate the mixture under vacuum (10–20 mbar) for a bubble-free result.
5. Pour into the mold in a thin stream from a low height within the 60 to 90 minute pot life.
6. Allow 8 to 10 hours to cure at room temperature (23 °C, > 40% relative humidity) before demolding.

Faster curing: hardener T 51 can be mixed with hardener T 47. At a ratio of 95:5 (T 51 : T 47), the pot life decreases to approximately 30 minutes and the mold can be demolded after approximately 4 hours. A higher proportion of T 47 accelerates further but shortens the processing window.

Note: pot life (working time) and demolding time are highly dependent on the mixing ratio and humidity. With more hardener or higher humidity, both pot life and demolding time will be shorter. Below 40% relative humidity, the surface may remain sticky; in that case, increase the humidity in the room.

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

This product is intended for the business market. For larger quantities or custom products, please contact us via info@nedform.com or +31 (0)46-3030989.

Professional Support

Are you unsure about the correct hardener choice or how to create a support shell for your mold? Our specialists will gladly help you select the right combination for your application. Feel free to contact us for advice.