Sunday, January 9, 2011

What is the difference between Polymer Clay Dolls / Figures & Ceramic Clay Dolls / Figures?

When you make a polymer clay doll or figure, the final figure is the finished artwork.

Polymer clay is very smooth, because whatever particles or chemical compounds that comprise it are definitely very, very miniscule. Once you are happy with the sculpture, the figure can be placed in a regular oven, with the temperature set to between 215 to 325 degrees Fahrenheit, the specific temperature depending on the brand or type of clay used. Polymer clay comes in many colors, which remain the same after the baking process, or the clay can be painted over and glazed.

On the other hand, ceramic figures go through a lot more steps / processes. Here is what I do.

I first sculpt using polymer clay. Each movable part is sculpted separately. As each piece is finished, it is placed in a small toaster oven, and baked for about 6 to 9 minutes. I use a toaster oven because the parts I make are small, and I am also not particular with the temperature - I can undercook or overcook the polymer clay, or even but it a little. This is okay because this is not the final set of pieces that would be the artwork.

Molds are made from the polymer clay pieces using plaster of paris. The molds have two to five pieces which are held together with rubber bands.  This is so that the ceramic clay can be easily removed from molds. The original polymer clay pieces are set aside.

Liquid ceramic clay (this is called a ceramic slip) is poured into the molds. The walls of the plaster of paris mold absorb some of the water in the liquid ceramic clay so a more solid clay begins to form, taking the shape of the mold. The middle portion of the slip will still be in liquid form, so after a few minutes of waiting for the clay to thicken, the excess liquid is poured out.

After a few more minutes, the clay inside the mold would be dry enough to be removed from the mold without losing its shape. The mold is dismantled, the clay is taken out and left to dry.

As the clay dries, certain steps can be done, but done at certain times best judged by an experience clay artist. Some notches and holes are carved out or drilled, and the excess clay from the seams of the mold is chiseled out or sanded. More drying is required.

Once dry, all the pieces are placed in the kiln. For the porcelain that I use, I set the kiln to about 2275 degrees Fahrenheit. This is why I call my kiln my little volcano. A regular baking oven cannot be used because "finalized" porcelain needs more than 5 times the temperature what is needed to bake a cake. In my mind, clay needs a volcano to fuse it. The kiln temperature rises by about three degrees per minute. Once it reaches 2275, I have the kiln programmed to hold that temperature for at least an hour, sometimes more. Then it slowly comes back down. The total process takes at least 13 hours and usually more. You cannot force the kiln to speed things up faster, and the same goes for the wait as the kiln cools down. The pieces are super hot, that they glow inside the kiln. You cannot force-cool the pieces because they are so hot, they can break easy when low temperature air comes in contact with them.

Color is applied, but the only usable colors are those for ceramics. Each layer needs to be "cooked" in the kiln, which means that if the colors need to be layered, as in the case of the eyes, the pieces need to be reheated in the kiln several times, and each time will need hours of heating and cooling, which means that the kiln stage alone can take days.

This explains why porcelain dolls take a long time to make. Also, in the case of ball-jointed dolls, the polymer clay stage also takes longer because I first sculpt the ball, bake the ball, then once it is hard, I attach to the ball the necessary part.

The reason why there are no ball-jointed polymer clay doll is that polymer clay is more brittle and much softer than ceramic clay. The parts can break off easily with just normal handling. On the other hand, ceramic / porcelain is like stone or glass. Porcelain does last forever, barring any accidental / unintentional breakage.

I hope you like this explanation. If you decide to work with either type of clay, however, you will need to read more, and to discover for yourself your own nuances, styles and revelations that only the actual experience of going through the process can provide.

If you have any questions, try to catch me on and I'll show you, live, what I have and what I go through to produce art for the collectors.

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