Porcelain for table top production requires at least two firings. First, what is called bisc fire, is a lower temperature firing @ 980*C. After such firing,
the porcelain surface is still porous, so it can easily absorb glaze. Porcelain objects at this stage are not fully fired yet; they are in their half manufacturing stage
waiting to be finished.
These half-products are being transferred for glazing. They are dipped in white, milk like consistency liquid, which contains silica, which under high temperature melts and forms crystal clear glossy surface. The temperature that all table top objects have to sustain is 1380*C. The environment in the kiln is so violent that it causes porcelain to shrink as much as 17-18%. During the high firing process the material not only shrinks but deforms, cracks and even explodes if a bubble of air is enclosed inside of the clay body.
But results are rewarding… If designed properly, the porcelain pieces come out pristine, elegant, shiny and pure. It truly takes a master to understand and control this medium and create a well-balanced, flawless object in porcelain.
photos by Bartek Jedrzejewski