The start of every firing begins by carefully placing each pot within the kiln's chamber to direct the path of the flame and soda vapor. This is the most important step in Helenske Clayworks' process requiring a great investment in time in order to predict the final outcome of the pots' surface.
Each pot must be placed with a barrier, known as a wad, between the vessel and any surface it touches, such as a shelf or another pot. This wadding is a special mixture of refractory clays that resist the corrosion of the soda and prevent the pots from becoming glazed to the surfaces they touch. As a means to further connect the work to the natural environment which inspires it, sea shells are used as the barrier.
Vapor Glazed Pottery
During the glaze firing sodium is introduced to the kiln starting at cone 9, about 2300 degrees F. In a soda firing sodium is introduced in the form of sodium bicarbonate and soda ash. The surface marks and colors created on the pots' surface are a direct result of the flame, time, oxygen levels and placement of pots within the kiln's chamber.
The vessels are placed in the kiln raw with no glaze applied to the outside surface, while some wares do contain a liner glaze on the pot's interior. The effects of the soda vapor in the kiln are a direct result of chemical reactions on the clay body, primarily through the interaction of the sodium with the silica and iron within the clay. Thus, the testing and experimenting with various clays is vital to creating beautiful surfaces to adorn Helenske Clayworks pottery.
The surface effects of using shells
Once fired the shells, composed of calcium carbonate, will disintegrate due to the moisture in the air. The shells are packed with wadding to give them strength and allow for intricate stacking formations. The marks are then washed and sanded in order to remove any rough edges.