What type of clay should I use?

Article courtesy of Smooth-On, Inc.

If you are making a mold and need to use clay for an original model or creating mold walls, your best bet is to use non-sulfur based clay.

There are several non-sulfur based clays to choose from a variety of manufacturers:


Van Aken

Sculpey (must be oven-cured first)

Monster Makers

IMPORTANT: Although these clays are advertised as sulfur-free, a surface compatibility test is always recommended to determine the suitability of any mold making rubber compound. Learn more about how to do a compatibility test. This list is intended as a guide and not a guarantee against cure inhibition.


This FAQ article is offered as a guideline and offers possible solutions to problems encountered during mold making and casting. No warranty is implied and it is up to the end user to determine suitability for any specific application. Always refer to the provided Technical Bulletins (TB) & Safety Data Sheets (SDS) before using any material. A small scale test is suggested to determine suitability of any recommendation before trying on a larger scale for any application.