Why Check for Undercuts Before Pouring Silicone Moulds

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Preparing your master for a resin table mould? One crucial step is ensuring you check for undercuts before pouring silicone, as this can make or break your final result.

What Are Undercuts and Why Do They Matter?

In mould making, an undercut refers to any indentation or protrusion on your master object that could trap silicone during demoulding. If undetected, undercuts make it extremely difficult or even impossible to remove the finished resin table from your mould without damage. Being aware of these features helps you plan how the mould should split and ensures both the silicone and your project stay intact.

How to Identify and Address Undercuts

Carefully inspect your model from every angle, paying close attention to sharp edges, lips, and any negative spaces under or around features. With intricate shapes, shining a light from different directions can reveal hidden recesses. For larger resin table forms, run a finger along the edges to detect subtle undercuts. If you spot any, consider filling them with a removable material, redesigning the master, or planning a two-part mould setup to simplify removal.

Choosing the right material is key when dealing with detailed or complex shapes. Flexible silicones like the “Liquid Mould” Casting Liquid Silicone Rubber are specifically formulated to handle significant undercuts and fine details, making demoulding safer and more reliable.

When Checking for Undercuts Makes a Difference

You’re working with intricate river table inlays or embedded details.
The table edges have decorative contours or overhangs.
You want to reuse your silicone mould multiple times without it tearing.

By carefully checking for undercuts, you reduce the risk of costly mistakes and save time on remakes.

Related guides

How Do You Make Silicone Moulds For Making Resin Tables

Checking for undercuts before pouring silicone is a small step that pays off with hassle-free demoulding and longer-lasting moulds. For more guidance and recommended materials for resin table mould making, see our detailed resources on creating silicone moulds for resin tables.