The Chocolate Mold Factory

Introduction to Silicone Molds

Many artisian chefs use FDA approved (food grade) silicone rubber to make custom chocolate molds.  Silicone is known for its ability to withstand temperature changes, ease of molding, low shrinkage, accuracy in reproducing fine details, and its ability to remain flexible.   The cost of silicone rubber molds is more than vacuum formed plastic molds; however, silicone molds can be made without spending as much on equipment. The only equipment you really need are mold forms, and preferrably, a degassing machine. 

To make a silicone mold you will follow some basic steps:

• Prepare the model and set-up mold forms.
• Spray a mold release agent over the model and forms.
• Prepare the silicone rubber mixture according to the manufacturers specifications.
• Remove air bubbles from the rubber mixture.
• Paint or pour the silicone rubber mixture over the model.
• Let the silicone harden or cure according to the manufacturers specifications.
• Remove the model and forms from the mold and trim as necessary.

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There are many different manufacturers of silicone rubber.  If you are going to be making chocolate or candy molds, you need to use a product that is food grade, meaning it is FDA approved for contact with food.  Two manufacturers that make such products are Dow and Smooth-On, although there are many others.  Silicone rubber can be purchased in many forms, including liquid and putty.  Both liquid and putty will come in a two part system.  One part is the rubber and the other is a hardener, or catalyst.  When researching silicones you will find that there are two types of systems, tin cured and platinum cured.  Platinum cured silicone systems are generally considered to be better, but are more expensive.  It costs around $100 per gallon, although you can buy it in smaller quantities.

Besides cost considerations, the only disadvantages of using silicone rubber to make molds is that air bubbles can be quite annoying and wreck a mold and the long cure time.  In order to solve the bubble problem, a degassing machine can be used to effectively remove bubbles.  There are also mixing and pouring techniques which can also limit the risk of bubbles. You can also avoid this problem by using silicone in a putty form, instead of a liquid form.

As far as cure time, it can take as much as 24 hours for a mold to cure.  This means you have to wait a long time to find out if your mold turned out right.  If it is wrong, you will have to repeat the process and wait again.  There are additives that you can use to speed up the process.  If you are like me, it is a little hard to find the patience to not touch or mess around with it to see how things are going.