Mould Making Calculator — Silicone Volume for Moulds

For most sculpture moulds, 10-15 mm walls are standard. Smaller pieces (under 10 cm) can use 8-10 mm walls. Larger pieces (over 30 cm) benefit from 15-20 mm walls for rigidity. Too thin and the mould distorts; too thick wastes expensive silicone.

Addition cure (platinum) silicone is more precise, has negligible shrinkage and is food-safe. Condensation cure (tin) silicone is cheaper but shrinks slightly over time and releases acetic acid. For fine art casting, addition cure is preferred.

A two-part mould uses more silicone than a block mould because the silicone surrounds the master on every face, including the top. The extra depends entirely on the proportions of the master — typically 20-50% more for a compact piece, less for a tall slender master and more for a flat wide one. Switch the Mould Type to "Two-part" and the calculator works out the exact figure for your dimensions rather than relying on a rule of thumb.

No. Once cured, silicone rubber cannot be melted or re-processed. However, silicone moulds last for dozens or even hundreds of casts depending on the casting material used. Resin and plaster are gentlest on moulds.