Silicone Addition Colourless 50 – Hard Platinum Silicone for Concrete & Heavy Casting Materials

Premium Hard Silicone for Professional Moulds and Heavy-Duty Applications

Silicone Addition Colourless 50 is a 2-component, platinum-cure (addition-cure) casting silicone with Shore A 50 hardness, specifically developed for sturdy, flexible moulds for concrete, cement and other heavy casting materials. This high-quality silicone combines high mechanical strength (8 N/mm² tensile strength) with minimal shrinkage (<0.1%) and good flow properties, ideal for durable moulds that can handle high-density materials. Easy 1:1 mixing ratio and adjustable hardness by mixing with the Shore A 5 variant.

Key Benefits

• Shore A 50 hardness: Relatively hard, sturdy moulds with excellent dimensional stability for heavy casting materials
• High mechanical strength: 8 N/mm² tensile strength and 14 N/mm tear strength for durable moulds that can withstand high pressure
• Suitable for high-density materials: Ideal for concrete, cement and other heavy casting materials without deformation
• Platinum-cure technology: Minimal shrinkage (<0.1%), no inhibition on most substrates, long mould life
• Good flow and self-de-airing: 13,000 mPa·s viscosity for good detail reproduction without vacuum treatment
• Adjustable hardness: Mixable with Silicone Addition Colourless 5 for any desired hardness between Shore A 5 and 50

Typical Applications

• Concrete moulds for precast elements, WetCast and decorative concrete applications
• Cement and plaster moulds for architectural ornaments and restoration
• Candle moulds for large, heavy candles and decorative wax objects
• Pad printing pads and flexible printing applications where hardness is required
• Industrial moulds for heavy casting materials and high-pressure applications
• Props and design objects where strength and flexibility are combined

Processing instructions:

1. Carefully mix components A and B in a 100:100 ratio (1:1 by weight) by hand or mechanically
2. Stir slowly in a figure-of-eight motion to prevent air entrapment
3. Process the mixture within the 30-minute pot life
4. Wait until fully cured before demoulding (3–6 hours at 20°C)
5. Curing can be accelerated by heat – every 10°C temperature increase roughly halves the time

Customisation options:

• Adjust hardness: Mix with Silicone Addition Colourless 5 for any desired hardness between Shore A 5 and 50. Example: for Shore A 18.5, mix 70% Shore 5 (35 g A + 35 g B) with 30% Shore 50 (15 g A + 15 g B)
• 
• Reduce hardness: Add silicone oil (note: migrates to the surface over time)
• Thicken for spreading: Add Silicone Thixo A or fumed silica
• Colouring: Use silicone pigment for intense colours

Silicones and More supplies high-quality silicones for professional mould making, concrete moulds, WetCast and industrial applications.

Important Warning: Inhibition in Addition-Cure Silicones

Please note: This is an addition-cure silicone (platinum-cure). These silicones can be inhibited by sulphur, nitrogen, amino compounds and metal salts. If you are unsure whether the products you are using (including gloves, spatulas and cups) contain these ingredients, please do a small test first. These substances are found in many latex gloves, some plasticines, paints and adhesives, condensation-cure silicones, 1-component silicone sealants, natural rubbers and 3D printing materials (especially stereolithography). If you still wish to use these, you will need to apply a protective layer of polyvinyl alcohol (PVA).

Professional Support

Our technical specialists advise on material selection, hardness adjustments, processing techniques and optimal results for your specific concrete or heavy casting application. Contact us for technical data sheets, processing guidelines or advice on preventing inhibition in addition-cure silicones.