Do I Need a Pressure Pot for RTV Silicone?

What Does a Pressure Pot Do?

A pressure pot is a sealed chamber designed to force air bubbles out of liquid silicone as it cures. This process is particularly useful when you are making extremely detailed or ultra-fine moulds, where visible air pockets could spoil the final cast. In a pressure pot, trapped air bubbles are compressed so they shrink or disappear altogether, resulting in much smoother casts.

When Is a Pressure Pot Necessary?

For most hobbyists working with craft, decorative objects, or small projects, using a pressure pot is optional. By pouring your silicone slowly and tapping the mould to encourage bubbles to rise, you can achieve successful results without extra equipment. However, if your project calls for high-precision or professional results—such as jewellery moulds or highly intricate models—a pressure pot can help elevate the finish of your moulds.

• Ultra-fine or industrial grade castings benefit most
• Projects with deep undercuts or many small details
• Highly visible or professional presentation pieces

Practical Tips for Reducing Air Bubbles

If you do not plan to use a pressure pot, focus on these methods for bubble reduction:

• Mix silicone gently to avoid introducing new air
• Pour silicone in a thin stream from a height for fewer bubbles
• Tap or vibrate your mould to encourage bubbles to rise and escape
• Consider a translucent silicone, like Pure Mould, to visually check for remaining bubbles