How should I store my rubber mold?

Article courtesy of Smooth-On, Inc.

People often underestimate the importance of proper storage of their molds. Improperly storing a mold can damage it and possibly render it unusable.

Proper Mold Storage

  1. Clean the mold cavity with a sponge and soapy water and let dry.
  2. Cast plaster into the mold and let dry. Do not demold. You will be storing the mold with the plaster casting in it to help maintain dimensional stability. Important: Do not use a urethane resin or epoxy for this step.
  3. If possible, place the mold with the casting in it in a black plastic garbage bag and seal tightly.
  4. Place on a flat level surface. Note: We have heard from customers who have inadvertently stored their molds with objects under them, causing the mold to permanently distort.
  5. Store in a cool, dry environment out of ultraviolet light.

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


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.