Wacker Elastosil M 4514® Part A – Condensation Silicone Base for Molds & Reproduction Casting

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

Elastosil M 4514 (A-component) is the base component of a pourable, condensation-curing (tin-cure) RTV-2 silicone rubber that vulcanizes at room temperature. This white, pasty base has a dynamic viscosity of approximately 35,000 mPa·s and a density of 1.26 g/cm³ (uncured). After curing, it forms a white, flexible mold with a Shore A hardness of approximately 25, a tensile strength of 4.5 N/mm², an elongation of 450%, a tear strength of 18 to 25 N/mm, and a linear shrinkage of less than 0.4%. The material is known for very good flowability and self-deaeration, and for excellent chemical resistance to polyester and polyurethane resins, which significantly extends the mold's lifespan.

Please note: this is exclusively the A-component. For processing, you need a hardener (B-component). For polyester resins, plaster, concrete, artificial stone, and wax, choose Catalyst T 51 (5%); for epoxy and polyurethane resins, choose Catalyst T 21 (5%). Pot life and demolding time depend on the chosen hardener; with 5% T 51, this is typically 60 to 90 minutes pot life and 8 to 12 hours demolding time.

Key Benefits

• Shore A hardness 25 (cured) – flexible mold that can be easily and damage-free demolded even with deep undercuts.
• Tear strength 18 to 25 N/mm – very high tear resistance for a long service life.
• Tensile strength 4.5 N/mm² and elongation 450% – high elasticity for significant stretching without damage.
• Base viscosity 35,000 mPa·s – very good flowability and self-deaeration for an air-bubble-free casting.
• Linear shrinkage < 0.4% (cured) – precise dimensional stability for detailed reproductions.
• Excellent resin resistance (polyester and polyurethane) – high number of copies per mold, even with aggressive casting resins.

Typical Applications

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

Processing Instructions

1. Choose the appropriate hardener: Catalyst T 51 for polyester, plaster, concrete, artificial stone, and wax; Catalyst T 21 for epoxy and polyurethane resins.
2. Stir the A-component thoroughly before use to distribute any sedimentation.
3. Weigh out in a 100:5 weight ratio (5 grams of hardener per 100 grams of A-component). Less hardener extends pot life and demolding time; more hardener accelerates curing but increases shrinkage. Never use too little hardener, otherwise the silicone will not cure (properly).
4. Mix A and B carefully and uniformly, scraping the sides and bottom of the mixing vessel thoroughly.
5. Preferably de-aerate the mixture under vacuum (10–20 mbar) and pour within the pot life in a thin stream from a low height.
6. Allow to cure at room temperature (> 40% relative humidity) before demolding; the exact time depends on the chosen hardener.

Faster curing: hardener T 51 or T 21 can be mixed with Catalyst T 47. At 95:5 (T 51 : T 47), the pot life decreases to approximately 30 minutes, and the mold can be demolded after approximately 4 hours.

Please note: pot life and demolding time are highly dependent on the mixing ratio and humidity. With more hardener or higher humidity, both will be shorter. Below 40% relative humidity, the surface may remain sticky; in this 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.

The standard combination of Elastosil M 4514 with Catalyst T 51 is also available as a ready-made kit.

This product is intended for the business market. For larger quantities or custom products, please contact us via info@siliconesandmore.com.

Professional Support

Not sure which hardener is right for your application? Our specialists will be happy to advise you on the correct hardener choice and mixing ratio. Please feel free to contact us.