The raw materials used to make them. Smooth-On never uses "off spec" or "waste stream" polyols that are often used to formulate foams for making products like furniture, shoes and other commodities. Smooth-On also uses filtered water in the production of its foams. As a result, Smooth-On foams have higher physical and performance properties than waste stream foams. With several densities to choose from, Smooth-On foams are premium formulations that are consistent from batch to batch ensuring the user a more predictable outcome every time.
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.