Guide: Casting a thin-walled food mould with Siliconen Culinair

In this guide you will learn step by step how to make a thin-walled, food-safe silicone mould from an existing model. Using the plasticine technique you cast a mould with an even wall thickness, ideal for chocolate, marzipan, ice cream and pastry. The mould is reusable and withstands both freezer and oven. Suitable for beginners and professionals alike.

📄 Download this guide as a PDF

What will you make?

You will create a thin-walled food-safe silicone mould from an existing model. By first applying a layer of plasticine of even thickness over the model, you create a hollow space with a constant wall thickness. You later fill that space with Siliconen Culinair. The result is a flexible mould that demoulds easily and lets you make countless impressions.

Siliconen Culinair is a platinum-cure silicone that is food-safe after correct processing and post-treatment. The mould is suitable for cold preparations such as chocolate and marzipan, but also for ice cream and even for baking a cake.

💡 Suitable for: chocolate, marzipan, mousse, fondant, ice cream and pastry. After post-treatment the cured mould is food-safe and withstands temperatures from freezer to oven.

Required materials

🛒 From the webshop

🧰 Provide yourself

The model you want to mould
Porcelain plaster for the outer mould
Flat, smooth surface (base plate)
Casing, for example a PVC pipe
Rolling pin and two 5 mm battens
Waterproof marker or pencil
Glue or screws to fix the model

Product specifications: Siliconen Culinair®

Property	Value
Mixing ratio	A : B = 1 : 1 (by weight)
Working time (pot life)	± 1 hour
Curing time	± 4 hours
Post-treatment	± 1 hour in the oven at 100–180 °C, then wash
Suitable for	Chocolate, marzipan, mousse, ice cream, pastry
Release agent needed?	Only for porous or sticky models

Preparation

Before the mould is cast, it is important that your master model is clean. Remove dirt, dust and unwanted imperfections, because the mould takes over every smallest detail of the model. Glossy areas return glossy in the mould, matte areas stay matte. Bring the model into its desired final state before you begin.

Treat the model with a release agent if needed. Porous or sticky materials can stick to the silicone; when in doubt, always make a small test on a hidden part first.

⚠️ Note: Always process the silicone wearing gloves and bear in mind the pot life of ± 1 hour. Make sure all materials are ready before you start mixing.

Step-by-step guide

Fix the model and seal the gaps

Fix the model with glue or screws to a flat surface so that it cannot float in the plaster later. Seal the gaps under the model with plasticine so that no silicone can flow underneath. With a waterproof marker, draw a tight line around the model on the base plate so you can place it back exactly later.

Fig. 1 – The master model glued to a smooth surface

Seal the seams

Check that all seams and gaps under the model are completely sealed with plasticine. This prevents silicone or plaster from flowing under the model later and distorting the shape.

💡 Tip: Smooth the plasticine seam with a spatula or your finger so that no sharp edges appear in the mould.

Seams and gaps under the model sealed with plasticine — Fig. 2 – Seams and gaps under the model are sealed

Roll out the plasticine to an even thickness

Roll out the plasticine with a rolling pin into an even slab of ± 0.5 cm thick. Place a 5 mm batten on each side and roll over these battens so that an even thickness forms everywhere — just like rolling out dough.

💡 Tip: For larger objects you can choose a thickness of up to 1 cm. The thicker the plasticine layer, the thicker (and stronger) the final silicone wall.

Plasticine being rolled out to an even thickness — Fig. 3 – The plasticine is rolled out to a thickness of ± 4–5 mm

Apply the plasticine over the model

Carefully apply the rolled-out plasticine over the model, following the shape roughly. At deeper areas, do not push the plasticine inwards but rather let it lie loosely over the model. Make sure the plasticine shape tapers so that the plaster outer mould releases from it well later. Smooth the outside with your fingers.

The model fully covered with plasticine in a releasing shape — Fig. 4 – The model fully covered with plasticine, in a releasing shape

Add the pouring funnel

Make a funnel from plasticine and apply it to the top of the covered model. This funnel will later serve as the pouring opening through which you pour the silicone into the mould.

A plasticine pouring funnel on top of the model — Fig. 5 – A pouring funnel on top of the model

Place the casing and mark the position

Place a casing around the model — for example a PVC pipe. With a waterproof marker, draw a tight line around the casing on the base plate and add a vertical mark indicating the exact position. Then seal the edges with plasticine so the plaster cannot run out.

⚠️ Important: The vertical position mark is crucial. With it you place the casing back exactly later, so that the model stays precisely in the centre of the plaster.

Casing around the model with the position marked — Fig. 6 – A casing around the model, with the position marked

Seal the casing and pour the plaster

Check that the casing is completely sealed with plasticine. Then pour plaster over the model until only the top of the plasticine funnel is still visible. Let the plaster cure completely according to the indicated time.

The casing sealed with plasticine — Fig. 7 – The casing is sealed with plasticine

Let the plaster cure

Let the plaster cure completely in the casing. The pouring opening (funnel) remains visible at the top. Do not move the setup during curing.

The casing filled with plaster, only the funnel visible — Fig. 8 – The casing is filled with plaster, only the funnel is still visible

Remove the model and plasticine

Remove the model including all plasticine from the plaster. Clean both the model and the inside of the plaster mould thoroughly — remove all plasticine residue and other dirt. The hollow space the plasticine leaves behind will later be filled with silicone.

Plaster and plasticine removed, model cleaned again — Fig. 9 – The plaster and plasticine are removed, the model is cleaned

Place the model back in the plaster

Fix the clean model back exactly in place, helped by the outline you drew earlier. Place the plaster with the casing back too, with the vertical mark exactly in the right position. The model now sits in the centre of the plaster and touches none of the edges. Fix the casing with a ring of plasticine, which also prevents the silicone from running out.

Fig. 10 – Model and casing placed back in exactly the same position

Mix and pour the silicone

Mix the Siliconen Culinair thoroughly in a ratio of A : B = 1 : 1. Then pour the mixture into a second container and stir again, so you are 100% sure of a homogeneous mix. Pour the silicone in a thin stream into the funnel, so that air bubbles can escape during the fall.

💡 Tip: Add a colourant to the B component before mixing. That way you can see at once whether the components are fully mixed. A vacuum pump is not necessary, but it improves the quality of the mould.

⏱️ Mind the pot life: After ± 1 hour the silicone is no longer ideal for pouring. So work promptly and make sure everything is ready.

The silicone mixture poured in a thin stream — Fig. 11 – The silicone mixture is poured in a thin stream

Cure, post-treat and demould

Let the whole thing cure in about 4 hours before you demould. Then remove the plaster outer mould and take the silicone mould off the model. Next place the mould in an oven at 100–180 °C for ± 1 hour for the post-treatment, and then wash it in soapy water or in the dishwasher. The mould is now ready for use.

💡 Tip: If the model has a lot of detail or protruding parts, add Silicone Oil 10 cSt to the Siliconen Culinair. This makes the mould more flexible and easier to demould.

The silicone mould after curing, ready to demould — Fig. 12 – After 4 hours you can demould the silicone

End result: the model cast in pure chocolate, melted in the microwave

Special notes

The mixing ratio of Siliconen Culinair is always A : B = 1 : 1 by weight. Weigh accurately for reliable curing.
Always pour the silicone in a thin stream and preferably from a height, so that air bubbles can escape during the fall.
The post-treatment in the oven (100–180 °C, ± 1 hour) is essential to make the mould fully food-safe before you cast food in it.
For models with a lot of detail or deep undercuts, make the silicone more flexible with Silicone Oil 10 cSt.
The mould is suitable for cold preparations such as chocolate and marzipan, but also for ice cream and for baking a cake.

Storage

Uncured components (A and B)

Store the closed packaging cool and dry, out of direct sunlight, between 10 °C and 25 °C. Close the packaging well immediately after use. Keep the A and B components separate and avoid cross-contamination of the caps, as even a small amount of the wrong component can cause premature curing.

Cured silicone mould

Store the clean, dry mould on a flat surface in a dark, dry room. Do not stack heavy objects on the mould to prevent deformation. Clean the mould after each use with soapy water or in the dishwasher, so it stays hygienic and food-safe.

Frequently asked questions

Is the mould really food-safe?

Siliconen Culinair is a platinum-cure silicone that is food-safe after correct processing and the post-treatment in the oven. Keep accurately to the 1 : 1 mixing ratio, let the mould cure completely and carry out the post-treatment of ± 1 hour at 100–180 °C before you cast food in it.

Why apply a layer of plasticine first?

The plasticine layer determines the wall thickness of your final silicone mould. By first applying an even layer of ± 0.5 cm and later replacing it with silicone, you get a thin-walled mould with the same thickness everywhere. That saves silicone and gives a mould that demoulds easily.

Do I need a vacuum pump?

No, a vacuum pump is not necessary. By pouring the silicone in a thin stream and from a height, most air bubbles escape during the fall. A vacuum pump does improve quality, but for most food moulds careful pouring is enough.

How do I make the mould more flexible?

Add Silicone Oil 10 cSt to the Siliconen Culinair. This lowers the hardness and makes the mould more supple, which is handy for models with a lot of detail or deep undercuts that are otherwise difficult to demould.

What can I use the mould for?

The mould is suitable for chocolate, marzipan, mousse, fondant and other cold preparations, but also for ice cream and even for baking a cake. Thanks to the temperature resistance of Siliconen Culinair you can use the mould from freezer to oven.

Guide: Casting a thin-walled food mould with Siliconen Culinair