How long can I store my rubber mold in a "mold library"?

Article courtesy of Smooth-On, Inc.

Library Life refers to how long a rubber mold will last in your “mold library”, just sitting on a shelf and not being used.  Some mold rubbers last longer than others.  Below is a chart giving you an idea of the library life you can expect from various mold rubbers:

  • Urethane (polyether based) e.g. ReoFlex®, VytaFlex®, some PMC® Series: 25+ Years
  • Urethane (polyester based) e.g. PMC®-724, PMC®-726: 1-7 Years (Moisture Exposure Dependent)
  • Silicone (economy tin catalyst) e.g. OOMOO® Series: 1 Year
  • Silicone ("Libra®" tin catalyst) e.g. Mold Max® Series: 5-7 Years
  • Silicone (platinum catalyst) e.g. Smooth-Sil®, Dragon Skin®, Mold Star®: 30+ Years
  • Polysulfide e.g. FMC® Series: 40+ Years
  • Latex: 10+ Years (With Proper Care)
  • Vinyl: 5+ Years (With Proper Care)

Related FAQ: How should I store my rubber mold?


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.