Is a Release Agent Always Needed When Working with Silicone Rubber?

Silicone Putty: Usually Release Agent Free

Silicone putties, such as “I–Gum”, are formulated to be non-stick and easy to use for most applications. Their inherent non-stick quality means a release agent is generally not necessary, especially when working with resin, polyurethane, wax, and similar materials. This makes silicone putty ideal for quick, hassle-free mould making with minimal preparation and easy demoulding.

Liquid Silicone Rubber: Sometimes a Release Agent Is Needed

Liquid silicone rubbers, like “Pure Mould” or “Liquid Mould”, may occasionally require a release agent. This depends on both the silicone’s formulation and the type of material you’re casting. For most resin, plaster, or wax castings, the silicone’s natural non-stick properties are often sufficient. However, if using sticky or particularly reactive casting materials, a release agent can help prevent the mould and cast from adhering, preserving mould life and ensuring clean release.

When This Matters Most

• Reusable Moulds: If you plan to reuse your silicone mould multiple times, a release agent may extend its lifespan.
• Complex Castings: For objects with deep undercuts or intricate shapes, release agents can help ensure trouble-free demoulding.