Thursday, September 8, 2011

Making My Improvised Ceramic Stilt

A ceramic stilt is a base or a stand with pointed sharp metal, which look like the tips of sharp nails, strutting out of them. Stilts are used so that the glazed surface does not touch anything, because anything touching will fuse together.

During the first firing, when no glaze or paint is used yet, pottery can be stacked on top of each other. Their sides can also touch, in the kiln.

Ceramic glazes and paints are like powdered glass. Once the pieces are glazed or painted, the pieces should not touch each other and the kiln sides and floor. The coats will fuse to whatever they touch, so if two pieces touch, they will fuse together.

If you go to the kitchen and look at your ceramic plates (and jars), the bottom part of the plate which touches your table or floor, called the “foot,” is usually unpainted and unglazed. Pieces like these do not need stilts. The way they were fired in the kiln is that a single plate is placed on top of a single tray and the trays are stackable. The manufacturers do not need to fuss around with stilts. A piece that is completely covered with glaze or paint, however, would need to be stilted.

The problem with the doll parts, the entire outside surface has to be painted, or glazed, or both. If stilts are used, there would be minute points on the surface of the pieces where stilts would have touched them while firing.

The idea I had was to skewer the doll parts, so the metal would touch the unpainted, unglazed inside surfaces during firing. Whatever material I use, it has to withstand the high temperatures in the kiln.

First, I got a few feet of high-temperature wire from the nearby ceramic supply store. This is wire that is supposed to withstand kiln temperatures, not ordinary galvanized iron wire.

  Secondly, the best material I had available to make the base of the stilts was porcelain clay. I cut up porcelain clay into thick rectangular pieces, and because they were thick, I poked holes in them to make sure that they don’t crack or break while drying and firing. It took me 10 days to wait for the blocks to dry. I initially embedded the wire into the blocks and then took the wire out, because I remembered that the porcelain would shrink during firing while the wire would not. So I redid the clay and let it dry with major holes, where the wires would go through, and minor ones, where the moisture would vent out. I used round, thicker toothpicks and let the toothpicks remain until the blocks were dry.

After firing the porcelain bases (Cone 6), I threaded the wire through the holes. I was finally able to skewer the doll parts and suspend them while firing. I glazed two sets of doll parts with transparent clear gloss, and had to fire them in two separate batches. The first was more precarious, because I fired the heavy parts first. The second was easier, but altogether, this experiment with the stilt and the first glaze took more than 2 weeks. The shaping and drying of the clay took about 12 days, and the three firings took 3 more days. I’m blogging because I’m still waiting for the 2nd batch of doll parts to cool down.

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