This was the result of a project in facial reconstruction I did as a part of my MSc Medical Art studies at the University of Dundee in Scotland. The aim of the project was to construct an anatomically accurate bust (ecorché) of the human head, with the internal physiolgnomyy on one side and the outer features on the other.
First the ecorché was modeled in clay, then cast in alginate and then plaster, and then cleaned up and painted.
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Step 1: Step 1 | Ingredients / Tools
skull (or skull model) sturdily mounted on some sort of post or stick
chicken wire (optional, but can save time and clay if you want to sculpt a neck)
glass eye (optional, makes the clay version look cool, but not actually needed for casting)
plaster / plaster bandages
plaster mixing bucket
newspaper (to cover work area)
a respectable anatomy text book of the head (particularly the muscles) I suggest Thieme or Sobotta
dental tools / old toothbrush
Step 2: Step 2 | Modelling the Face
Starting with a stable mounted skull on a base, build up the different muscles on the skull according to the anatomy text book. I'm not going to list them here, 'coz you can also just model up any muscles you want, make new ones, etc., depending on what result you are going for. If you are going for anatomically accurate, however, I will point out that there are muscles in the face that are involved in facial expression and muscles involved in mastication (chewing), and take note of both 'deep' muscles and 'superficial' muscles. You will want to build the model up with deep muscles first followed by superficial muscles.
Step 3: Step 3 | Preparing the Clay for Mould Making
In the case of this project, we created a 'relief' ecorché, which means a '3d without being 3d' sculpture, as it were. (The back is flat, with the head extruding from the surface.)
Once you've finished building up the muscles and face, a flat background/frame has to be built around the face in clay. This will serve the purpose of keeping the alginate and plaster from dripping past the area you want a mould of. Basically build a thick layer of clay around the perimeter of your face. Most efficient is at a maximum 90% angle to the face, more than that means that plaster can dry around your face and make it immensely difficult to remove the cast from the mould.
Step 4: Step 4 | Making the Preliminary (alginate) Mould
Cover your sculpted clay with alginate (mixed with water at a ratio of 4:1 water to alginate), until you have a thickness of approximately 1-1,5 cm. Make sure the surface is evenly covered without any air pockets.
Step 5: Step 5 | Plaster Stage
Allow the alginate to dry (a few minutes) and then cover in clingfilm to create a barrier between it and the plaster layer. Wet and apply plaster bandages to create a stronger mould, followed by a layer of plaster approx. 1 - 1,5cm thick. Allow plaster to dry (we waited a couple of hours)
Step 6: Step 6 | Removing the Mould
At this point the plaster mould needs to be removed from the sculpture and the alginate peeled away. Be careful in small areas of detail. Clean out any clay from the mould that may have gotten stuck when removing the sculpture; basically you want to perfect the reverse image of your sculpture that has been created via alginate and plaster. A wet toothbrush and/or dental tools are helpful for hard-to-reach areas.
Step 7: Step 7 | Casting
With the mould turned hollow side up and stabilize (with clay, styrofoam, etc) Cover the inside of the mould with a thin layer of dish soap to help ease removal of the mould after casting.
Then mix a new batch of plaster and pour it into the mould. Let sit for 1,5 hours. Then turn cast around and remove the mould.
Your cast is ready. It will need cleaning and possibly sanding to get rid of tiny imperfections, and you can choose to paint it if you like as well. Enjoy!