Premium Pourable Addition Mold Rubber for Professional Reproduction and Concrete Mold Applications

Silicone Addition Green 30 is a pourable, addition-curing (platinum) RTV-2 mold rubber that cures at room temperature without chemical shrinkage. The two components are mixed 1:1 by weight and each has a viscosity of 8,000 mPa·s, with excellent flowability and self-degassing. Once cured, it forms a green rubber with a hardness of Shore A 27 and a tear strength of 20 N/mm. The pot life is 60 minutes and the mold can be demolded after 6 hours at 23 °C. Thanks to its good resistance to common reproduction materials and its high tear strength, this mold rubber is especially suited to molds of models with many undercuts, to concrete molds and to dimensionally accurate copies.

Key Benefits

• Hardness Shore A 27 – flexible enough to demold models with extensive undercuts, holes and gaps.
• Tear strength 20 N/mm – the mold does not tear easily when demolding thin and narrow parts.
• Tensile strength 5 N/mm² and elongation at break 450 % – strong, stretchable rubber with stable long-term mechanical properties.
• No chemical shrinkage – dimensionally accurate casts, even with large and complex molds.
• Mixing ratio 1:1 by weight – easy to weigh and process.
• Pot life 60 minutes, demoldable after 6 hours – plenty of working time, and curing can be accelerated considerably with heat.

Typical Applications

• Concrete molds for decorative and architectural elements.
• Reproduction molds of models with extensive undercuts.
• Molds for casting resins in small series.
• Dimensionally accurate copies of models and parts.
• Molds for ornaments, reliefs and decorative pieces.

Processing Instructions

1. Stir component A and component B separately and thoroughly first.
2. Weigh A and B in a 1:1 ratio by weight. Only use components with the same lot number.
3. Mix slowly and carefully, preferably in a figure-8 motion, to limit air entrapment.
4. If desired, degas the mixture in a vacuum chamber immediately after mixing.
5. Pour within the 60-minute pot life.
6. Allow the mold to cure for at least 6 hours at 23 °C. A higher temperature speeds up curing; air bubbles then have less time to escape.

Important Warning: Inhibition of Addition Silicones

This is an addition-curing silicone (platinum cure). Curing can be disrupted by sulfur, nitrogen, amine compounds and metal salts. These substances are found in, among others, latex gloves, some modelling clays, paints and adhesives, condensation silicones, 1-component silicone sealant, natural rubber and certain 3D printing materials. If in doubt, run a small test first or apply a separating layer of polyvinyl alcohol.

Silicones and More, specialist in high-quality mold rubbers and casting materials for professional makers.

Professional Support

Looking for a softer, even more free-flowing variant? Take a look at Silicone Addition Yellow 25. Unsure which mold rubber best suits your model or casting material? Contact us at info@siliconesandmore.com, we are happy to help.