How do I correctly mix silicone for moulds?

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Accurate mixing of silicone rubber is fundamental for achieving precise and durable moulds. A well-blended mixture minimises defects and enhances both detail and longevity in the finished result.

Measure Silicone Precisely by Weight

Most silicone rubbers for mould making, such as “Pure Mould”, require a strict ratio for mixing—often 1:1 by weight between the base and the catalyst or hardener. Always use digital scales, not volume measurements, for accuracy. Accurate weighing is crucial, as even small variances can lead to incomplete curing or a tacky finish.

Mix Slowly and Avoid Air Bubbles

Combine the silicone liquids in a clean container, blending with a spatula. Mix gently in a steady, circular motion, scraping the sides and bottom until the mixture looks fully homogeneous. Take care to avoid rapid stirring, which introduces air bubbles; bubbles undermine detail and reduce mould strength. If working with a particularly low-viscosity silicone, tapping the container can also help bubbles rise to the surface.

When Accuracy Matters Most

Precise mixing and bubble-free silicone are especially important when moulding small objects or capturing intricate details, such as with jewellery, figurines or prototypes. For these cases, using a highly detailed casting silicone, like “Liquid Mould” – Casting Liquid Silicone Rubber, ensures your process yields professional results.

Related products

• "Pure Mould" – Translucent Liquid Silicone Rubber for Mould Making
• "Liquid Mould" – Casting Liquid Silicone Rubber, 5-40 Shores, Bi-Component A+B
• "I–Gum" – Non-Toxic Silicone Putty for Mould Making

Related guides

• How Do You Make Moulds With Silicone Rubber

Mastering the mixing process underpins the entire silicone rubber mould-making craft. For further insight into successful mould creation, explore our main guide on how to make moulds with silicone rubber.