How many castings can I expect to get out of my rubber mold before it becomes unusable?

Article courtesy of Smooth-On, Inc.

This is known as the "production life" of your mold. There are a number of variables that can affect production life. Below are some tips for getting the most out of your molds.

  • What are you casting into the mold? Different casting materials will affect your mold in various ways. Candle makers casting beeswax, for example, have gotten hundreds of castings out of a single mold. On the other hand, you may only get a handful of castings if you are using a chemically harsh resin.
  • Did you use a release agent? The single best thing you can do to extend the production life of your mold is use a release agent each time before casting. Based on customer feedback and in-house testing, you could get as many as double the number of castings from a mold by using a release agent.
  • What type of mold are you using? Certain mold rubber and casting combinations yield better results. For example, VytaFlex™ urethane rubber holds up well to the abrasive nature of concrete casting; Mold Max™ XLS II and Smooth-Sil™ 936 are especially resistant to chemically harsh resins. Pro Tip: check the technical bulletin for advice on suitable mold and casting options.
  • How long are castings left in the mold? If a casting material is chemically affecting the mold rubber, the longer it is in contact with your mold the more damage it is doing. Demolding as soon as possible will help extend the mold's production life.

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.