How to Make Your Own Custom Silicone Mould

If you want to experiment with unique forms or simply build something yourself, you can easily create a custom silicone mould.

It is important to have a good negative mould when creating resin castings or jewellery with epoxy resin, however these can be purchased in a variety of designs.

In this tutorial, I’ll guide you through how to make your own simple flat top silicone mould for resin.

What you’ll need for making your custom silicone mould:

• An item to cast
• Silicone rubber - Recommend 1-2-1 Easy Mould 2 part silicone
• Gloves
• Measuring cup or jug
• A stir stick (Lolly Stick)
• Plastic container or cookie cutter
• Wide sticky tape
• Mould release (OPTIONAL)

Choose an item you want to use to create your mould from. For this tutorial I’ve used a selection of different shaped objects with a variety of textures and patterns.

Get a non porous container to house the casting, particularly something plastic with a flat bottom. Depending on the size of the mould you are making you can use a cookie cutter as housing instead of a container.

TIP: Try not to pick something that is a lot bigger than the piece you are casting as this will waste a lot of your silicone rubber.

Using a container:

Temporarily stick the item inside the container to stop it from moving and to help stop silicone going underneath the item. I use tape but you can use hot glue or clay.

Using a cookie cutter:

Cover one end of the cookie cutter with sticky tape, making sure to completely seal the edges, then place the item inside, an added bonus is that the tape will help keep your item in place too.

OPTIONAL: Lightly spray mould release before pouring your silicone rubber. This is might be useful depending on the material of the item(s) you are casting. This will need about 10 minutes to dry thoroughly.

Once you’ve arranged your pieces in a way you are happy with, it’s time to get all your mixing equipment together. Put some gloves and safety glasses/goggles on, grab a jug/cup and a mixing stick.

Mix the silicone rubber according to the package instructions. Curing time will depend on the brand of silicone rubber you are using. I’m using a 1:1 ratio silicone that sets clear in just under 2 hours.

Gently pour the mixed silicone rubber into the container or cookie cutter, keeping a steady narrow stream in one place. Aim for the base as this will help eliminate trapped bubbles, especially if your item has grooves. Cover it with at least one centimetre of silicone. 

Leave your mould on a flat surface and preferably in a dust free environment to cure.

The curing process can take anywhere between one to 24 hours to complete. Again this will depend on the silicone type and brand you are using.

Once curing is complete peel the silicone out of the container/cookie cutter and remove the master item(s).

Your newly created mould is ready to cast with. 

TIP: Use mould release before each pour, as this will help prolong the life of your mould.

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