Silicone Rubber for Complex or Undercut Moulds

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Creating successful moulds with fine undercuts or deeply detailed shapes requires a silicone rubber that can flow precisely and capture every contour. Here, we explore options tailored for complex moulds and offer essential preparation tips.

Choosing the Right Silicone Rubber

For intricate or undercut moulds, liquid casting silicone rubbers are most effective. These are designed to flow into tight recesses, ensuring every detail is captured, even in tricky geometries. For example, “Liquid Mould” is specifically formulated for ease of pouring, making it ideal for models with deep negative spaces or elaborate designs. “Pure Mould” silicone is also suitable, offering transparency so you can check the mould’s accuracy during filling.

Preparation and Application Tips

Start by preparing your model and mould box, ensuring they are completely clean. Mix your silicone components thoroughly as per product instructions; for most, this is a 1:1 ratio. Pour slowly from one corner to allow the material to envelop details and minimise air bubbles. For highly detailed or complex objects, tapping the mould sides gently can help the silicone settle deeper into undercuts. Patience during curing—typically several hours—ensures improved results.

When Silicone Choice Really Matters

Picking the appropriate silicone rubber truly matters when working with models featuring undercuts, fine engraving, or challenging negative spaces. The flow characteristics and cured flexibility of liquid rubbers allow de-moulding even after they have filled delicate or complex features, preventing tearing or distortion.

Related guides

What Type Of Silicone Rubber Is Used

Whether you’re moulding resin miniatures, decorative ceramics or jewellery masters, the right silicone ensures a faithful, reusable mould. For further guidance on the types of silicone rubber used in mould making, explore our main FAQ on what type of silicone rubber is used.