Tips for Preventing Bubbles in Polyurethane Resin

Mixing Techniques for Fewer Bubbles

To minimise trapped air, it’s essential to mix polyurethane resin slowly rather than vigorously. Avoid aggressive stirring, which can introduce more air. Instead, fold the two components together gently until fully blended. Pour the mixed resin carefully into your mould, allowing the liquid to flow in gradually and settle on its own.

Using a high fluidity resin like IWhite can further reduce bubbles, as it fills detailed moulds easily.

Preparing Tools and Moulds

Any moisture can react with polyurethane, leading to bubbles or other surface imperfections. Ensure all tools, mixing containers, and moulds are completely dry before use. Warm resin and moulds (but not hot) can also help as cold temperatures can encourage bubble retention.

When Bubble-Free Resin Matters

Bubbles are especially problematic for projects requiring sharp detail, such as miniatures, small parts, or transparent doming. Careful preparation ensures your finished piece has a professional quality and consistency, which is vital for rapid prototyping and decorative work.