Making a silicone mask for Halloween

You know them from films and from Halloween: masks that move when you talk, with wrinkles, pores and a stare that makes the neighbours jump. That is silicone. And yes, you can make a mask like that yourself.

We will be honest with you, though: a mask that covers your whole head is the hardest project you can take on with silicone. The good news is that it nearly always goes wrong in the same place. Once you understand that one principle, you are already ahead of most beginners.

Full mask or half mask?

First a choice, because it decides whether you will be busy for one weekend or several.

A full mask, also called a pull-over mask, goes over your head like a hat. It takes three to five weekends and you need a head form and a three-part mould. Allow € 200 to € 350 for materials, not counting the head form. That sounds like a lot, until you see that a professional mask costs € 300 to € 700 or more.

A half mask or a separate prosthetic piece, such as a nose, a forehead or a cheek with a nasty wound, can be made in one weekend for € 60 to € 120. You glue it to your skin, so the fit does not have to be accurate to the millimetre.

Never worked with silicone before? Then start with the half mask. You learn to mix, colour and cast without a failure immediately costing you several weekends of work.

The secret is in the core

This is where most guides drop off. They show you how to sculpt a face and how to pour silicone, but skip how the two come together.

A mask is hollow. So you need two forms: an outer mould with all the details of the face and a core that forms the inside. The silicone goes into the space between them.

The trick: you sculpt the face directly onto the core. The clay you apply is later literally replaced by silicone. If you apply 3 to 5 millimetres of clay everywhere, you get a mask that is 3 to 5 millimetres thick. You do not have to measure a gap anywhere, because it is already built into your sculpture.

That is why you start with the head form and not with the clay. The best core is a cast of your own head (never make one on your own). A ready-made mask core works too. A reinforced polystyrene head will do for a monster, but for a realistic face it is often too small.

From head form to mask in six steps

1. The core. A hard, smooth head form with a flange around the neck. You use that flange later to line the core up in the mould.
2. Sculpting. First an even layer of clay 3 millimetres thick, then the large shapes and finally the wrinkles and skin texture. Everything that is in the clay will show up in the mask.
3. The outer mould. Two shells of plaster and plaster bandage, one at the front and one at the back. A single piece will not work, because the chin, ears and neck lock it in place.
4. Clay out, core back in. You clean everything and put the core back into the mould. The empty space is now exactly your mask. Bolts or ratchet straps hold everything in place.
5. Casting. You brush a thin layer of silicone into the details, pour the rest into the mould and slowly lower the core into it. The silicone rises up around the core. Then leave everything alone for at least one night.
6. Finishing. Demould the mask, cut open the eyes, nostrils and mouth, paint it and powder it with talc.

Sounds manageable. In practice the sting is in step 4. If the core sits even a few millimetres off-centre in the mould, the mask ends up too thick on one side and too thin on the other. So take your time here and check the flange around the neck before you close the mould.

Five mistakes when making a silicone mask

Learning from other people's mistakes is cheaper than learning from your own.

Using ordinary modelling clay. Many clays contain sulphur, and platinum silicone, the type you use for masks, cannot tolerate it. You get sticky patches that will never cure. The same happens with latex gloves. Choose sulphur-free clay and nitrile gloves, and always do a test patch first.

Not drilling air vents. Air wants to rise and gets trapped in the tip of the nose, the chin or your demon's horns. A 3 to 4 millimetre hole at every high point solves that.

Adding too much softener. In American tutorials you see mixtures that are one third softener. That recipe is meant for wounds that you stick onto the skin. A pull-over mask becomes sticky from it and tears when you put it on. Keep it to a maximum of 10 to 20 percent of the total weight, or leave the softener out.

Skimping on thickness. Anything thinner than 3 millimetres tears when you pull it on. Around the eyes and mouth keep at least 4 millimetres. Thinner does not save you any weight worth having, only a tear.

Painting with acrylic paint. Looks beautiful, until the first time you pull a funny face. Then it all flakes off. Only silicone paint adheres to silicone. You make it yourself from a little silicone, white spirit and pigment.

What do you need?

The basis is a skin-safe platinum silicone. For a first mask we recommend Elastosil FX 20. It is slightly firmer than the softer FX 10 and therefore less likely to tear when you pull the mask over your head.

You will also need, among other things, sulphur-free modelling clay, plaster and plaster bandage for the mould, silicone pigment and scales that weigh accurately to the gram. With this silicone you mix the two components exactly 1 to 1. "Roughly right" does not exist with silicone.

A full mask weighs 500 to 800 grams. Still mix 1 to 1.2 kilos, because some of it disappears into the seam, the air vents and the bottom of your cup.

Ready to get started?

You will find all the silicones, pigments and tools for masks and prosthetic pieces in the collection Silicone for Masks and SFX. For each product you can also read which documentation on skin contact is available.

Unsure about the core, the mould or how much material to order? Feel free to ask us via our contact form. We have worked with silicone ourselves for many years and are happy to think along with you.