Do You Need a Release Agent with Silicone Rubbers for Moulds?

← Back to Where can I buy silicone rubber for moulds in Mentana?

Do I Need a Release Agent When Using These Silicones?

When working with silicone rubbers for mould making, many wonder if adding a release agent is necessary. The advice can depend on the type of silicone and the surface you’re moulding from.

Release Agents and Liquid Silicone Rubber

With quality liquid silicones, such as “Pure Mould” silicone rubber, a release agent is not typically required for models made from non-porous materials like glass, metal, or certain plastics. The liquid silicone cures with low adhesion to these surfaces, so the mould can be easily demoulded after curing. If you’re working with porous materials (wood, uncoated plaster), a thin layer of release spray or wax may be advisable to prevent sticking or material absorption.

Preparation with Silicone Putty

Products like “I–Gum” silicone putty are specifically designed for quick and easy use—without needing a release agent in most cases. The putty is naturally non-stick on a wide range of surfaces, making it perfect for moulding small objects, resin jewellery, or prototype items. Always ensure surfaces are clean and dry for best results, and test an area if you are unsure about compatibility with unusual materials.

When Surface Types Make a Difference

You are unlikely to need a release agent with these silicones when working on smooth, sealed objects. However, for intricate models with deep cavities or when reusing a mould repeatedly, a light application can promote a longer mould life and cleaner releases. If you are unsure, start without one—then introduce a release agent only if you notice sticking or surface marking.

Related guides

Choosing the right silicone rubber simplifies mould removal and often removes the need for extra preparation. For more guidance on sourcing and working with silicones, see our hub on where to buy silicone rubber for moulds in Mentana.