Face casting

In a few months, it's time for Elf Fantasy Fair again! The costume I have in mind requires a mask. More specifically, a rigid, skull-shaped mask. To make sure it fits comfortably on my head, I made a cast of my face, wich I will use for sculpting the mask on.
Making a face cast isn't that easy. You can't do it by yourself, so I called in some help. My wife, her mom and stepdad and one of our friends were glad to help me. And we got the entire process on video!

Materials
To make a cast of a body part, you can use either silicone or alginate. Alginate is much cheaper than silicone, but an alginate mold dries out quickly and isn't permanent. Immediately after molding, you have to make a plaster cast, before the mold dries out, and after that, it's thrown away. So, here's the stuff you need:

• Alginate (I used Smooth On Alja Safe Acrobat, a fibre reinforced alginate)
• Plaster bandages
• Vaseline
• Gloves
• Plaster
• Clay

Alginate is a powder derived from seaweed. It's mixed with water to make a slurry that sets into a rubbery consistency. Pure alginate is quite runny and not easy to use for making a cast of a face, the fibre reinforced type I used is designed especially for use on vertical surfaces.

Preparations
The first thing I did was drawing an outline for the alginate on my face using a sharpie, and then I greased up my entire face using vaseline. Alginate releases from skin quite easily, but eyebrows or other facial hair need to be protected or you risk getting the alginate stuck to your face. I have a short beard, wich wasn't really a problem. A swimming cap is very useful to protect your hair, but since I'm bald that wasn't needed!
Before we mixed a batch of alginate, we cut a roll of plaster bandage into 30 cm strips so everything was ready. Keep in mind to wear clothes that you don't mind getting dirty (they will no matter how careful you are)! I used a large trash bag with some holes cut in it to protect my clothes.
And one very important thing: make sure you have a comfortable chair! I sat on a regular chair, and I had to tilt my head back the entire time. Towards the end, my neck started to hurt quite a bit! Some sort of beach chair would have been a lot better.

The procedure
First, your entire face except your nostrils is covered in alginate. The powder is mixed at a one to one ratio by volume with water. As soon as it's mixed, the clock starts ticking! The Alja Safe Acrobat sets very fast, it starts thickening after five minutes. I had mixed way too much, and we had to throw some away. It's better to mix up small batches.
The most challenging part is the nose, because the nostrils have to be kept open so you can breathe. Don't put straws up your nose, that's way too uncomfortable. I used the back of a sharpie to block one nostril at a time while my crew was putting cold goo on my face.
After the alginate has set, it needs to be reinforced. Alginate by itself is very flexible and tears easily, so it needs a support shell. This is easily done using plaster bandages. Simply dip them in water, and build up a plaster shell over the alginate. It takes about fifteen minutes for these to fully harden, after wich the mold can be removed.


Finishing
After the plaster has hardened, it's time to remove the mold from your face. Some tutorials tell you to remove the plaster and alginate separately, other recommend removing them together. I removed them together so the alginate was supported all the time.
We carefully peeled the edges off my face first, while I used my facial muscles to slowly loosen it from the inside. Take your time for this, you don't want to damage the mold! It works best if you tilt your head forward, support the plaster shell with one hand and use the other to get the mold off your face.
After removing the mold, you first have to plug the nostrils with some clay, and then immediately pour plaster in it. An alginate mold isn't permanent and dries out quite fast. I used Ultracal 30, a mixture of plaster and cement that's very strong and durable. This stuff sets slowly, so you don't have to rush things. At first, I was afraid I didn't mix it right because it took so long to set. It took an hour before it started to thicken, and the next morning, it had set.
After the plaster has set, you remove the alginate and plaster bandage; they can be thrown away now. The plaster casting probably needs some cleaning up around the nose. In my case, there were some minor flaws around my mouth. Because we underestimated how fast the alginate set, we had to tear off a piece and start over again, but it's not really a problem.