How do I choose between Body Double silicone and Alja-Safe alginate for lifecasting?

Article courtesy of Smooth-On, Inc.

Both options have pros and cons. Here are a few things to consider to help decide which to use for your project.

Benefits of Body Double™ Silicone

  1. Molds made with Body Double have good tear strength and will last a long time, and can be used repeatedly to make many copies (castings) of your original model. An alginate mold is destroyed after one use. On the off chance that you can use an alginate mold more than once, you need to do it fast. As an alginate mold begins to dry out, it will shrink and deteriorate quickly.
  2. With casting options, you are limited by what you can cast into an alginate mold – usually plaster. You can cast almost anything into your Body Double mold. You can cast liquid plastics, wax, plaster, low temperature melt metal alloys, concrete and other materials to make your reproduction.

Benefits of Alja-Safe™ Alginate

  1. Alja-Safe alginate costs much less than Body Double silicone rubber.
  2. Alginate does not stick to anything. You don’t need a release cream for most applications. You can make a mold of the hair on your head with alginate by using hair conditioner as a release agent. You can’t make a mold of the hair on your head with Body Double. The best you can do is make a mold using a plastic bald cap.

Which option reproduces better detail?

Both materials will reproduce perfect detail down to a fingerprint.


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.