Why Is My Silicone Mould Not Curing Properly?

← Back to How do you make silicone moulds for making resin tables?

When your silicone mould refuses to cure or remains tacky well after the recommended time, it can disrupt your entire resin table project. Let’s explore the main reasons, troubleshooting steps, and how to get your moulds setting perfectly every time.

Common Causes of Incomplete Curing

• Incorrect Mixing Ratios: Silicone mould rubbers are typically mixed in precise ratios, often 1:1 for easy-use options like Pure Mould or specialised putties. Deviating from these ratios, even slightly, can leave the mixture soft or sticky.
• Ambient Temperature: Cool temperatures will slow curing considerably; silicone prefers stable, warmer environments (usually around 18–25°C).
• Insufficient Mixing: Uneven mixing, with material left unmixed on pot edges, leads to uncured patches.

Practical Steps to Prevent Curing Issues

• Measure Carefully: Use accurate digital scales or the supplied measuring tools. Always follow the product’s instructions (for example, a 1:1 ratio with “I–Gum” putty or Pure Mould liquid silicone).
• Mix Methodically: Scrape the sides and base of your mixing container to avoid unmixed spots. Mix for the time suggested by the product, until colour and texture are uniform.
• Control Temperature: Work in a room where the temperature won’t drop during curing. If it’s cool, consider gently warming the room or using a warming mat to maintain a steady environment.

What To Do If Your Mould Isn’t Setting

If your mould is slow to cure, allow extra time in a warm, dust-free area. If it remains sticky after the extended time, unfortunately, it’s rarely salvageable and typically must be remade, making double-checking ratios and temperature crucial for the next attempt. Consider a reliable and user-friendly product such as Pure Mould for consistent results.

When This Matters Most

Accurate curing is especially critical when making detailed or large-scale silicone moulds for resin tables—mistakes can lead to wasted time and materials, so careful measuring and environment control are essential.

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 Silicone Moulds For Making Resin Tables

Understanding why silicone moulds sometimes fail to cure helps ensure smoother, more successful resin table projects. For more practical tips and in-depth mould-making methods, see our comprehensive guide to silicone moulds for resin tables.