Understanding How Long Silicone Molds Last

The lifespan of a silicone mold is a significant concern for both mold makers and casters, referring to the number of successful castings that can be made with a single mold. However, it is a question without a clear answer, as there are many factors that can affect the service life of molds. Let's explore them.

silicone mold casting plaster

The lifespan of silicone molds can vary attributable to several factors, primarily being influenced by the quality of the mold, frequency of use, and the type of materials cast.

The quality of silicone molds is primarily influenced by the type of silicone material and the thickness of the mold. For RTV-2 silicone materials, the optimal performance is achieved with a hardness of 20-30 Shore A. If the hardness is higher or lower than this range, the tear strength of the silicone will gradually decrease. Additionally, tin-cure silicone with the same hardness has better tear strength compared to platinum-cure silicone. Using the brush-on mold-making technique and incorporating a layer of fabric such as gauze onto the silicone can significantly enhance the mold's lifespan. Although this may incur higher time costs, it often balances out against material expenses. Furthermore, vacuum degassing during the silicone mold-making process is another method to improve the mold's durability.

In addition, for casting materials, pouring materials that generate heat into the mold can accelerate the aging and deterioration of the mold. Common heat-generating materials include polyurethane resin, epoxy resin, etc.

Below, we have also listed the approximate casting counts for common materials using silicone molds. Please note that these figures are for reference only, as the mold size, dimensions, intricacy of undercuts, surface details, and frequency of use can vary for each project.