Does this silicone require preparation before use?

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Casting silicone for mould making typically consists of a bi-component formula that requires preparation before use. The process involves thoroughly mixing two separate parts—often a silicone base and a catalyst or hardener—in a precise ratio specified by the manufacturer. This step is essential to ensure the silicone cures properly, resulting in moulds that are flexible, resilient, and detailed.

Does this silicone require preparation before use?

If you’re new to making prototype moulds with casting silicone, understanding its preparation is crucial for a successful result. Bi-component silicones do not cure unless both the base and catalyst are combined in the correct ratio.

Mixing Components: The Essential Step

Almost all casting silicones—including renowned products like Pure Mould – Translucent Liquid Silicone Rubber—are supplied as two separate parts. Before pouring, you’ll need to measure and blend these components (often in a 1:1 ratio, though you should always check the product’s instructions for variations). Mixing must be thorough to avoid patches of uncured silicone, ensuring even curing and a robust final mould.

Handling and Practical Guidance

In practice, wear gloves and use clean mixing tools to prevent contamination. Slowly combine the two parts in a clean vessel, stirring from the edges and bottom, minimising air bubbles. Some users gently tap the container or briefly apply a vacuum or pressure pot for highly detailed or bubble-sensitive projects. For silicone putty like “I–Gum”, simply knead equal parts together by hand until a uniform colour is achieved.

When Preparation Matters Most

For intricate or fine-detail moulds where incomplete mixing could spoil results.
When rapid prototyping depends on fast curing and consistent mould quality.
If you plan to reuse moulds: proper preparation maximises durability and longevity.

Related guides

Correct preparation of bi-component silicone underpins successful rapid prototyping and ensures moulds will be both detailed and durable. For more on choosing and working with silicones for robust prototype creation, visit the Silicone for rapid and durable prototypes hub.