Platinum vs Tin
Mold making silicone is typically derived from one of two families, tin-based “condensation cure” silicone, and platinum-based varieties known as “addition cure.” Among each grouping are a wide variety of formulations, featuring Durometers (hardness), viscosities, working times, and cure times. While the two can be used for similar applications, they each have unique benefits that set them apart. Let’s examine these differences.
1. Platinum-Based Molds
Platinum-cured silicones are used in a variety of applications. Its use of platinum in the catalyst makes it a very dimensionally stable, clean, and long-lasting silicone. Because of this, it’s the standard in the medical, product development, and food industry. Their long-lasting dimensional stability makes them the clear choice for long-term use molds. Once cured, platinum molds have a greater temperature and chemical durability than their tin counterparts. However, platinum-based compounds are prone to inhibition (contamination, causing silicone to not cure). You must be aware of the materials platinum-based silicone will be in contact with. This includes pouring against sulfur-based clay, low quality paint/primer, natural rubber, and even tin-based silicones, amongst others.
