I spent the last few months searching for a sulfur-free modeling clay that would not react negatively with my mold making materials. After several failed attempts with “sulfur-free” clays ordered off of Amazon.com, I decided to check out the Polytek brand.
Full disclaimer: I bought the clay with my own money. I was not asked to post this review. I will get nothing if you order from this company. I simply love their products.
When making silicone molds, you need a sulfur-free, non-hardening modeling clay. Otherwise, you risk pouring a silicone mold that simply will not harden. Because Polytex makes and sells silicone and liquid rubbers for mold making, I bought the clay they were selling on their website.
Poly Plasticine Clay
https://polytek.com/products/poly-plasticine-clay#
The clay is not hard, but not too soft. It is relatively easy to shape, although it is trickier to carve (hard clay works best for carving, but it kills my hands).
Best thing about this clay is that I have had zero molding issues when working with it.
- It holds its shape for molding.
- It cleans up easily and is ready for reuse.
- It works great for sealing up the edges of the molding forms I make.
- Relatively inexpensive.
Anyway, if you have been having problems with silicone hardening, order a block Polytek’s clay and see if it makes a difference.
