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Ceramic Art Lesson Plan: Translucent Porcelain

Posted By Antoinette Badenhorst On September 20, 2010 @ 12:19 pm In College Level Ceramics Assignments,Education,Lesson Plans 9-12 | 1 Comment

 

 

Pedestal pot, glazed with a red glaze on the inside with water etching outside and the rim cut out. Electric fired to cone 10.

Goals

 

  • Research the work of artists using translucent porcelain for wheelthrowing, handbuilding and moldmaking. Analyze how the material adds to or detracts from the concepts, form, techniques and craftsmanship of the work.
  • Plan and design forms that are appropriate for throwing with translucent porcelain and that conceptually consider the material’s qualities.
  • Learn techniques to throw and trim basic forms using this clay, then move on to creating forms from your designs and sketches.
  • Experiment with glazing strategies that support your design ideas.

 

 


Download a printer-friendly version of this ceramic art lesson plan here:
Translucent Porcelain

 


Throwing

Before throwing porcelain, it’s important to adequately plan and design what you’ll be making. Porcelain contains more silica and feldspar (the glass-making components in clay bodies) and less clay (the plasticizers in clay bodies), so the body is very open and porous. This means that it is more difficult to work with than other clays since it becomes saturated with water so quickly and collapses much faster.

For best results, wedge porcelain twice: once a little earlier—even a day—then right before use. Once you have centered the clay, coning is also important. Use removable bats to throw on.

 

Fig.1

Fig.1

Fig.2

Fig.2

Fig.3

Fig.3

 

When opening the clay, pay attention to the original planning of the bowl. Most of the bowls I create are curved in the bottom so I start with curving the inside. The first two pulls of the clay are quick and intended to create height for the basic shape (figure 1).

 

Use just enough water or slurry to keep a wall of clay moving above your fingers (figure 2). The slightest dryness can distort the bowl and you might have to start over, so use a sponge to control the release of moisture. Since porcelain is very thirsty and readily absorbs water, it quickly becomes too soft to work and control. Frequently clean water from the inside and make sure the original contour of the bottom is still in place (figure 3).

 

Fig.4

Fig.4

Fig.5

Fig.5

Fig.6

Fig.6

 

 

Thin, shape and compact the walls with the tip of your wet fingers (figure 4). Then, with the wheel at a medium speed, use as much time as needed to create the desired shape on the inside of the bowl. If the inside shape is successful, you can easily trim the outside to follow the inside since it is easier to trim unwanted clay away from the outside.

 

Use two plastic kidneys, one on the inside and one outside, to squeegee excess slip off and eliminate throwing rings without distorting the form (figure 5). Leave extra clay on the bottom of the sides to provide extra support until the form sets up (figure 6).

 

Trimming

 

About 30 minutes after you’ve finished throwing, cover the piece and protect it from uneven drafts. With porcelain, you don’t want the rims to dry out too fast. You also want to avoid uneven drying, which causes cracking and warping in many porcelain pieces rather than the speed at which it is drying.

 

Fig.7

Fig.7

Fig.8

Fig.8

Fig.9

Fig.9

Once the piece has reached firm leather hard, return it to the wheel in an upright position and attach it to the plaster bat. Using very sharp tools, trim away any ridges and thick parts on the inside of the bowl. Use a round loop tool that follows the inside curve of the bowl (figure 7). A metal kidney helps create a smooth surface (figure 8). Follow with a damp sponge and a rubber kidney to compact the clay.
Trim the unwanted thickness on the outside using a sharp pointed wooden tool (figure 9). Next, with the pot still upright and on the bat, use a loop tool to trim excess clay and throwing marks from the outside surface (figure 10). Continue trimming the whole form until you get the thinness you want. It’s easier to work faster and more aggressively while the clay is still fairly soft and the walls thicker. However, when the clay is soft, it’s easy to cut too deep or create an uneven surface. As the walls become thinner and drier, use a lighter touch and sharper tools.
Fig.10

Fig.10

Fig.11

Fig.11

Fig.12

Fig.12

Since the bottom is still attached to the bat, you can accurately judge the wall thickness without having to handle the pot too much. Porcelain becomes dry quickly and the thin walls need very careful and limited handling to prevent them from cracking.

By the time the clay releases itself from the plaster bat, it’s dry enough to trim the foot rim. Very carefully place the bowl with the rim down and centered on a foam-covered bat (figure 11). The bat has holes that fit onto the pins on the wheel head and the foam is marked with rings to help me find the center with the least handling of the pot.

Using a Surform blade, remove any bumps and roughness created by the cutoff tool. The final step is to create the shape you originally planned trimming with a series of contoured loop tools (figure 13). I carefully choose tools that allow me to create the right curve at the bottom, and I also trim the whole piece again right down to the rim (figure 14).

Fig.13

Fig.13

Fig.14

Fig.14

The last tool needed to finish is a metal kidney. Trim the final unevenness away and follow with a damp sponge and a plastic kidney to compact the clay.

By now the whole action becomes a fine balance between the character of the clay and the skill of the potter. If that stays in harmony, it is possible to create beautiful pottery.

 


Antoinette Badenhorst is a ceramic teacher, writer (in her mother tongue, Afrikaans), workshop presenter and demonstrator for more than twenty years. She exhibits her work in leading art galleries in South Africa, the USA and Japan. For the past twelve years she has worked with porcelain at different temperatures. You can contact her at timakia@yahoo.com.


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