What is the Correct Mixing Ratio for Liquid Silicone Rubber?

Standard Mixing Ratios Explained

Most liquid silicone rubbers designed for mould making use a simple 1:1 ratio by weight or volume—one part base (A) to one part catalyst or hardener (B). This straightforward approach makes it accessible even for beginners. Carefully check the individual product instructions as some specialist silicones may require different ratios.

• For example, “Pure Mould” Translucent Liquid Silicone Rubber is designed for easy 1:1 mixing and fast curing in 3–8 hours.
• Silicone putties such as “I–Gum” also rely on a 1:1 mix for consistent, reliable results.

How to Achieve the Best Results

For precise moulds, always measure each part as accurately as possible—the slightest deviation in ratio may impact curing and flexibility. Use clean mixing containers and tools to avoid contamination. Mix thoroughly until the material is homogeneous, as partially mixed silicone will not cure correctly and can compromise detail reproduction.

When Mixing Ratio Matters Most

Strict adherence to the recommended ratio is especially important when producing highly detailed or complex moulds, such as jewellery pieces or technical prototypes. Proper mixing maximises both the lifespan and the quality of your finished mould.