What will you make?

You will make a food-safe series mold with which you produce several identical models in a single pour, for example dessert shapes, chocolate, or pralines. You start with a master model (the original that represents the desired end result), make a master mold from it to produce copies, and then cast the final series mold around a series of those copies. The end result captures every detail of the original and is ready for immediate use in the kitchen.

Required materials

Preparation

An idea is always the beginning. That can be an existing object you want to copy, such as fruit, nuts, or stones, or your own design such as a company logo, model, or handmade creation. For every mold you need a tangible starting model: the master model. This model represents exactly the desired end result, because your production mold becomes a one-to-one copy of this model.

If your idea is not yet tangible, first make it three-dimensional. Modeling by hand is possible, but for a clean final model you are better off using a 3D printer or milling machine, possibly outsourced to a plastics processing company. If you supply your design in the correct file format, the model can be milled from plexiglass, for example.

Before you cast the mold, it is essential that your models are completely clean. Remove dirt, dust, and unwanted imperfections, because the mold picks up every smallest detail. Glossy parts return glossy in the mold, matte parts stay matte. Then set out all materials ready for use.

Step-by-step guide

Fix the master model

Place your master model in a container and make sure no silicone can run underneath and that the model does not float. Glue the model down fully or fit the underside with double-sided adhesive tape. A well-fixed model is the basis for a clean master mold.

Mix silicone for the master mold

Mix the silicone in the correct ratio of 1 : 1 very well and work as accurately as possible. Pour the mixture into a second container if necessary and mix well again (two-cup method), so that you are sure of a homogeneous mixture.

💡 Tip: To save costs, you can use a cheaper silicone for the master mold. After all, the master mold does not come into contact with food at this stage.

Cast the master mold and demold

With a thin stream, pour the mixture over your model until it is completely covered. Then pause briefly and brush over the model with a brush so that any air bubbles definitely disappear. Then continue casting the mold with a thin stream.

Let the silicone rest for at least 2 hours before you demold. After that, the master mold is ready to cast replicas with.

Cast replicas

With the master mold, cast the desired number of replicas. Porcelain plaster is a nice product for this: it flows well and picks up all details perfectly. If your model has fragile parts and you want extra strength, then choose A1 Acrylic Resin or a hard Polyurethane casting system.

Make as many replicas as you want to include models in the series mold. In this example we work towards a mold with twenty models.

Arrange models and place the border

Place the replicas in a logical arrangement on a flat, even, and releasing surface. Do not keep too much space between the models (that costs unnecessary silicone) but also not too little (too tight gives a risk of cracks later). Fill gaps under the models with plasticine clay and make sure everything is fixed to the bottom so that nothing floats. Lay the surface nicely level.

Then fit a border around the models so that the silicone cannot run away. Use a formwork of metal, plexiglass, or lacquered wood, or glue clamps that you tighten firmly. Seal holes and gaps under the border with plasticine. The border must always extend above the model, but never make it too wide.

💡 Tip: If you would rather not make a border, use a clean plastic container with a flat bottom that is not too big or too small.

Mix Silicone Culinary

Pour the required amount of A-component into a mixing container and add the B-component in the correct ratio of 1 : 1. Silicone Culinary is a 1 : 1 system that, after curing, is suitable for processing food.

Mix the whole thing very well with a stirring stick and go carefully along all edges and corners so that the silicone is evenly mixed everywhere. Pour into a second container if necessary and stir again (two-cup method).

💡 Tip: Do not make tapping movements while stirring, this beats in unnecessarily many air bubbles. A vacuum pump is not a requirement but does benefit the quality of the mold.

⏱️ Mind the potlife: Silicone Culinary has a processing time of ± 40 minutes at 20 °C. Too large a deviation in the mixing ratio can make the cured silicone sticky. Make sure everything is ready before you begin.

Cast the series mold

Pour the silicone with a thin stream and from one point. This way, air bubbles still get the chance to escape during the fall and the air is pushed ahead of the silicone instead of being trapped. Pour until all models are completely covered.

💡 Tip: For a guaranteed bubble-free contact layer, you can first pour part of the silicone over the models and brush it out with a brush. Once the complete model is provided bubble-free with a thin layer, then fill the mold further.

💡 Tip: Place your mixing cup next to the cast mold. From the leftovers in the cup you can feel whether the silicone has cured without touching the mold itself.

Cure, demold, and finish

Let the whole thing cure for approximately 2 hours before you demold. The mold is ready for use after that, but the final strength is only guaranteed after 1 day (full strength according to technical data). Finally, cut away any thin skins on the outer edges with a sharp knife on a cardboard or wooden mat.

⚠️ Food application: If the mold is going to process food, post-cure the mold after curing. Place the mold in an oven at 80 °C to 100 °C for 2 to 3 hours so that any vapors degas. Then clean the mold with dishwashing liquid and dry it well. Only fully cured, post-cured silicone may come into contact with food.

End result: a clean series mold for twenty models at once, ready for use in the kitchen

Technical data Silicone Culinary

Potlife and demold time are strongly dependent on the temperature. At a higher temperature, the processing time and the demold time become shorter.

Special instructions

• Do not expose the mold to temperatures below −40 °C or above +280 °C for prolonged periods.
• Do not let the mold come into contact with the heating element of an oven.
• Place the rubber mold on an oven dish or baking tray for more stability.
• All kinds of objects lend themselves as a model, such as toys, nuts, stones, and shells. Porous materials and paper or fabric can cause problems with releasing, in which case use a release spray or sealer.
• Materials containing salts, sulfur, or amines disrupt the curing process.
• Do not wait longer than an hour between two casting layers, otherwise there is a chance that the layers no longer adhere to each other.

Cleaning

Clean the mold after use with warm soapy water and rinse it with plenty of water. Drying is easy in the oven at 150 °C.

Storage

Uncured silicone (A and B component)

Store the closed packaging between 10 °C and 25 °C, cool and frost-free, out of direct sunlight. When stored correctly, the shelf life is at least one year. Close the packaging well immediately after use.

Cured silicone mold

Store the mold in a dark space between 10 °C and 25 °C at a humidity of approximately 50 percent. Do not stack molds under heavy objects to prevent deformation.

Use in combination with food

Silicone Culinary is an addition-curing silicone based on platinum catalysis. This silicone complies with the FDA guidelines and is TÜV-certified. Only the cured silicone may come into contact with food. We recommend first post-curing the mold after curing before you use it.

Frequently asked questions

Why do I work via a master model and a master mold?

The master model represents the desired end result, the master mold makes it possible to quickly produce several identical replicas. With those replicas you then build up the series mold. This way you cast a mold for several models at once in one go, without damaging the original.

May I use a cheaper silicone for the master mold?

Yes. The master mold does not come into contact with food and only serves to make replicas. A cheaper silicone suffices at this stage. For the final series mold, however, always use food-safe Silicone Culinary.

How much space do I leave between the models?

Not too much and not too little. Too much space costs unnecessarily much silicone, too little space increases the chance of cracks in the mold. Keep an even, limited distance and fill gaps under the models with plasticine.

Why do I pour with a thin stream from one point?

A thin stream gives air bubbles the chance to escape during the fall. By pouring from one point, the air is pushed ahead of the silicone instead of being trapped, which results in a bubble-free mold.

What is post-curing and when is it necessary?

Post-curing means placing the cured mold in an oven at 80 °C to 100 °C for 2 to 3 hours so that any vapors degas. This is necessary when the mold is going to process food. Then clean the mold with dishwashing liquid and dry it well.

How long does the mold last?

A well-maintained series mold of Silicone Culinary lasts countless pours. The silicone has a very high tensile strength and a low shrinkage of less than 0.1 percent. Clean the mold after each use and store it according to the storage advice.