Wacker Cenusil® M 825 A/B – Pourable Addition Silicone for Concrete Molds & Reproduction Molds

Premium Castable Addition Silicone for Professional Concrete Mold and Reproduction Module Applications

Wacker CENUSIL® M 825 A/B is a castable, addition-curing 2-component silicone rubber that cures at room temperature with a Shore A hardness of 25, a white end product, and excellent self-deairing properties. With a pot life of 60 minutes and a demolding time of 6 hours at 23°C, this product offers ample processing time for complex molds. The mixing ratio is 1:1 (A:B) by weight — the simplest mixing protocol in its class. CENUSIL M 825 is ideally suited for applications where shrink-free curing, deep undercuts, and excellent resistance to common reproduction materials are essential.

Key Advantages

• 1:1 Mixing Ratio by Weight: Easiest processing in its class — no weighing errors, direct application without a calculator
• Excellent Self-Deairing: Low viscosity of 8,000 mPa·s and active self-deairing eliminate air bubbles without a vacuum pump
• Shrink-Free Curing: No chemical shrinkage — dimensionally accurate reproductions of complex models with deep undercuts
• High Tear Strength (20 N/mm): Molds release easily even with narrow cavities, holes, and gaps without tearing
• Excellent Long-Term Stability: Mechanical properties remain stable over many casting cycles — ideal for series production
• Resistant to Common Reproduction Materials: Good resistance to casting resins, concrete, plaster, and wax

Typical Applications

• Concrete molds for architectural elements, facade panels, and decorative concrete
• Reproduction molds of models with deep undercuts and complex geometries
• Molds for plaster casting, synthetic resin, and restoration work in museums and heritage conservation
• Prototyping and series production in industrial design and engineering
• Molds for decorative objects, relief panels, and architectural ornaments
• Reproductions for the art sector and scenographic use in film and theater

Processing Instructions:

1. Stir components A and B separately and thoroughly before use
2. Mix A and B in a 1:1 weight ratio — use only components with the same lot number
3. Mix slowly and carefully in a figure-8 motion to minimize air entrapment
4. Optional: vacuum immediately after mixing (processing is still possible up to 60,000 mPa·s)
5. Pour within the 60-minute pot life
6. Allow to cure for at least 6 hours at 23°C — accelerated curing is possible by increasing the temperature

Wacker Chemie AG is a world leader in the development and production of silicones for industrial and technical applications. The CENUSIL series is specifically developed for reproduction and concrete mold applications where dimensional accuracy and durability are paramount.

Important Warning: Inhibition in Addition Silicones

Please note: This is an addition silicone (platinum-cure). These silicones can be inhibited by sulfur, nitrogen, amino compounds, and metal salts. If you are unsure whether the materials you are using (gloves, spatulas, molds) contain these substances, first do a small test. Inhibiting substances are found, among others, in latex gloves, some plasticines, condensation silicones, 1-component silicone sealants, and certain 3D printing materials. If in doubt, apply a layer of polyvinyl alcohol (PVA) as a release agent.

Professional Support

Our technical specialists advise on processing techniques, mold design optimization, curing acceleration, and the right choice for your specific concrete mold or reproduction module application. Contact us for technical data sheets, processing manuals, or product advice.