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RESION Silicone Casting Rubber Shore A40 is a platinum-cure RTV-2 silicone rubber designed for producing rigid moulds for demanding applications. The silicone rubber is hard, durable, food-safe and produces moulds with excellent dimensional stability and outstanding detail reproduction.
Thanks to its simple 1:1 mixing ratio, this platinum silicone is easy to use and suitable for both beginners and experienced users. Shore A40 Silicone Casting Rubber is the hardest grade in the RESION range and is the preferred choice for applications where the mould must withstand high pressure or the casting temperatures of low-melting metals, such as tin and copper.
Key features of silicone casting rubber
Platinum cure (addition-cure): clean curing with minimal shrinkage.
Shore A40: hard and rigid, offering maximum dimensional stability and pressure resistance.
1:1 mixing ratio: easy to measure and mix.
Low viscosity: pours easily with minimal air entrapment.
High tensile and tear strength: for long-lasting moulds with complex shapes.
Food-safe: independently tested and certified by TÜV SÜD as suitable for food contact (Report 7216021999, September 2026), in compliance with EU and German food contact regulations.
Heat resistant: up to 200°C continuously and 300°C for short periods.
RESION Silicone Casting Rubber Shore A40 has been independently tested by TÜV SÜD for food safety and complies with European and German regulations for materials intended to come into contact with food (EC 1935/2004, EU 2025/40, Resolution AP(2004)5, LFGB and the BfR recommendations).
What is Shore A40 silicone rubber used for?
Shore A40 is the ideal choice when you need to produce rigid, dimensionally stable moulds that can withstand high loads, for applications such as:
Concrete moulds and moulds for casting tin and copper. The high Shore hardness and heat resistance of up to 300°C make Shore A40 Silicone Casting Rubber the preferred choice for moulds used to cast heavy casting materials or low-melting metals.
Moulds for epoxy resin castings where excellent dimensional stability is required.
Food-safe applications where the mould needs to remain rigid, such as moulds for chocolate, sugar and confectionery.
The high Shore hardness provides maximum dimensional stability, making Shore A40 an excellent choice for series production with consistent dimensions.
Processing platinum silicone casting rubber
Accurately weigh Component A (base, blue) and Component B (hardener, white) in a 1:1 ratio using a scale.
Mix both components thoroughly but gently for approximately 3 minutes using a mixing spatula. Scrape the sides and bottom of the mixing container well. Then transfer the mixture to a clean container and mix briefly once more.
Slowly pour the silicone rubber into the prepared mould or mould box. The working time is approximately 45 minutes at 20°C. At higher temperatures, curing will occur more quickly, but trapped air bubbles will escape less easily.
After approximately 8 hours, the silicone rubber is fully cured and tack-free.
Add a silicone thickening agent to convert this casting silicone into a brushable or spatula-grade silicone.
Specifications
Packaging
Base (SR1-40A)
Curing agent (SR1-40B)
1 kg
0.5 kg
0.5 kg
2 kg
1 kg
1 kg
6 kg
3 kg
3 kg
20 kg
10 kg
10 kg
200 kg
100 kg (10 x 10 kg)
100 kg (10 x 10 kg)
400 kg
200 kg (drum)
200 kg (drum)
Also availabe in other Shore hardnesses
Looking for a softer silicone rubber? RESION also offers the following easy-to-mix 1:1 variants:
Order RESION Silicone Rubber Shore 40 and all other silicone rubber products easily from Polyestershoppen.com. Place your order on working days before 5:00 PM CET, and it will be dispatched the same day. If you have any questions about this product or would like advice on another application, visit our information centre feel free to contact one of our specialists.
Product properties
The key technical properties clearly listed in one place.
Article number
SIL000594
The technical product category, such as primer, resin, hardener or cleaner. It explains the product's purpose and helps you find other products with a similar function.
Silicone casting rubber, Platinum Cure RTV-2
Mixing ratio indicates how much of each component is needed, for example resin (A) and hardener (B). A ratio of 100:50 by weight means 100 grams of A to 50 grams of B; by volume you might use millilitres. Weight and volume ratios are not necessarily the same because the components may have different densities. Accurate measuring is important for proper curing.
1:1
Colour
Zwart
Hardness describes a material's resistance to indentation. For silicone rubber and other elastomers, the Shore A scale is commonly used: Shore A 15, for example, is softer than Shore A 40. Harder plastics may be rated on the Shore D scale. The number belongs to its Shore scale and is not a unit like MPa; values on different scales cannot be directly compared.
Shore 40
Density describes the mass of a material per unit volume. Values may be given in g/cm³, kg/L or kg/m³; 1 g/cm³ equals 1 kg/L. For example, one litre of a liquid with a density of 1.2 kg/L weighs approximately 1.2 kg. Density helps convert between weight and volume, but it can vary with temperature.
1.02 kg/dm³
The period for which an unopened product remains usable under the specified storage conditions. Check whether the period starts from the manufacturing date or another date. Shelf life may be shorter after opening, especially for products sensitive to air or moisture.
24 months
Cure shrinkage describes how much a resin, adhesive or rubber becomes smaller as it cures. The value is usually given as a percentage (%) and may refer to volume shrinkage or shrinkage along one dimension; these are not the same. Shrinkage matters for casting accuracy and for limiting stress or distortion.
Low shrinkage after curing
Food contact suitability means that a material may come into contact with food under specific, defined conditions. This suitability does not automatically extend to every application.
Food type: for example water-based, acidic or fatty foods.
Contact time and temperature: brief contact may have different requirements from long-term storage or contact with hot food.
Processing: correct mixing ratio, full curing and any required post-curing may be conditions of approval.
A fully cured or odourless product is not automatically food-safe. Check the manufacturer's declaration or technical documentation for the permitted use.
Yes
Heat resistance describes the temperature a material can withstand after correct processing and curing, usually expressed in degrees Celsius (°C). Continuous exposure is different from a brief temperature peak, and mechanical loading may also affect the limit. Heat resistance is not the same as the temperature at which the product can be applied.
Up to 200 °C (short-term up to 300 °C)
Curing time is the period a product needs to reach a specified stage of cure. It is usually given in hours or days, often at a reference temperature such as 20 °C. A product may be tack-free or safe to handle before reaching its full mechanical and chemical resistance. Film thickness and mixed quantity may also affect the time.
8 Hours
Safety information
Read the warnings and use appropriate protective equipment before handling the product.
