Mixing Ratios & Working Times for Silicone Rubber Moulds

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Mixing Ratios and Working Times for Silicone Rubber

Selecting the right mixing ratio and understanding the working time is essential for successful silicone mould making. This guide covers key points for popular silicone rubber options.

Understanding Mixing Ratios

Both “Pure Mould” and “I–Gum” silicone rubbers are user-friendly, requiring a simple 1:1 ratio. Just combine equal parts of each component and mix until homogeneous. For “Liquid Mould”, you’ll need to add a specific catalyst to the base—carefully follow product instructions for best results.

Always measure by weight or volume as directed.
Mix thoroughly to ensure no unmixed portions remain.
Avoid under- or over-mixing, which may affect the cure quality.

If you’re seeking a translucent, detailed finish, “Pure Mould” translucent silicone rubber is an excellent choice.

Working Times and Curing

Working times can vary depending on product and temperature. “I–Gum” putty offers a generous working time of up to 20 minutes, allowing you to shape and apply it at your pace; the mould is typically ready within 20–40 minutes. “Pure Mould” sets in around 3–8 hours, making it ideal for both swift hobby use and professional results.

For “Liquid Mould”, pot life may range from 20 minutes up to several hours. Always begin pouring soon after mixing to avoid early thickening, and allow sufficient curing time before demoulding. Cure speed can be influenced by ambient conditions, so a warmer room may accelerate the process slightly.

When Accurate Timing Matters

Keeping an eye on working time is crucial when making large or intricate moulds. Rushing can compromise detail, while taking too long may result in the rubber starting to cure before pouring. Planning in advance ensures you get the best results, especially with complex pieces or multiple batches.

Related guides

Getting the mixing ratios and working times right is the foundation of successful silicone mould making. For further step-by-step advice, explore the main How do you make a mould with silicone rubber? guide.