A ceramic portrait bust needs to be hollow in order to be fired in a kiln, it can be made in two different ways: either as a solid mass which is later hollowed, or it can be built directly as a hollow form.
The method I’ll show you here is building up the bust as a hollow form. It’s a good choice if you know from the outset that you’ll be firing it, rather than using it as a basis for a cast, for example in Bronze.
Hollow building has the advantage that you avoid potential damage during the hollowing process. However, because of it being hollow, you need to work in a different way than you may be used to. Creating the sculpture from the bottom up. You are able to adjust it later, but it’s good to be as accurate as possible as you go along.
Start with good water-based clay that has a high grog content, the grog makes it more stable and reduces shrinkage.
Use a wire to cut thick strips of it straight from the bag and form an H shape as shown here. The front and back are the chest and shoulder blades of the bust. Think of the middle line as a kind of backbone for your bust, it will stabilise the structure right up into the head.
Keep building up, layer after layer, making sure to join the strips by squishing them hard and avoid trapping air.
When you reach the top of the shoulders and want to join front and back, you may have trouble keeping the stability for the arch of the shoulder, it helps to build a temporary pillar to support the damp clay of the shoulder.
Build up the shoulders and neck, keeping a careful eye on your subject to capture the individual details of the muscles and bones in the neck which can be particularly beautiful in young people. This is also a good time to add clothing details or jewelry.
Continue building up the neck and chin, keeping the centre partition.
At this point, I find it helpful to create an accurately proportioned profile on the middle partition to use as a guide.
Check to make sure the neck and shoulders match up properly to the profile of the head.
Slowly work outwards from the profile line to create the chin and mouth area, then gradully work on the width of the nose.
I like to pinprick the centre partition as I go along, this allows any air bubbles to escape during firing.
Once this is all in place, focus on getting a likeness in the nose and mouth area.
Keep the model damp by spraying frequently with water and by wrapping the bits you’re not working on in plastic bags.
I complete the cheeks and back and sides of the head before I start working on the eyes.
As the lower parts of the sculpture harden, they can usually take the additional weight as I build up the bust.
However, the face may get rather heavy for the neck of the sculpture to hold up, so I like to rest the chin on a support as I work.
Once I’m happy with the face, I finish building up the back, sides and top of the head and then close the sculpture at the crown.
When the head is complete, and before I work on surface textures or details, I pinprick through to the inner cavity on the entire sculpture. The pin-pricking ensures that any air bubbles I may have trapped can escape during firing.
I smooth the surface, create the texture details and let the whole thing dry very slowly before firing.