Another term for "Brush-On Mold" is blanket mold. Blanket molds resemble a thin blanket of rubber placed around the model and are generally 1/4″ to 1/2″ thick. Blanket molds are made either by:
1) brushing or spraying flexible mold rubber onto a model and then creating a mold shell around it (the brush-on method generally requires application of multiple layers of rubber)
2) pouring the rubber into a previously constructed mold shell that is situated around the model.
In all cases, construction of a rigid mold shell, also known as a “mother mold”, is required in order to keep these thin molds in the proper shape and position for casting. Mother molds can be made from a number of materials, including polyurethane plastic.
In the two-part tutorial below, we show you how to make a brush-on silicone mold of a pumpkin, create a plastic mold shell, and then rotocast a reproduction of the pumpkin.
Tutorial - Part One - How to Make a Brush-On Mold with Mold Shell
Part I of this video tutorial demonstrates how to make a brush-on mold using tin-cured silicone rubber (TinSil® 80-30 Silicone Rubber).
Tutorial - Part Two - How to Make a Brush-On Mold with Mold Shell
In Part II, we construct the mold shell (using Poly 1512X polyurethane plastic), cut the mold, and make a plastic casting using a rotational casting machine (using EasyFlo 120 polyurethane plastic).