D.
J. Hale
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POTTERY PROCESS GREENWARE Pottery is considered “greenware” from the time it is formed until it is placed in the kiln for it’s first firing. First the clay is wedged (kneaded to remove air pockets and ensure consistent moisture throughout). Then the desired shape is formed with the clay on the potters wheel. At this point the clay is very impressionable and can’t be handled or bumped without effecting it’s shape so it is set out to dry and firm up a bit. Depending on the dryness of the air and thickness of the pot it will eventually firm up enough that it can be handled. At this point it is called “leather hard”. By keeping the pot covered with plastic or moist newspaper this stage can be maintained . It is during the leather hard stage that excess clay is trimmed from the bottom of the pot, designs are cut out or carved, and handles or extra pieces are added. When all the decorating is complete the pot is set out to dry thoroughly. It cannot be placed in the kiln until it is “bone dry” as any moisture left will boil at 212 degrees and cause the piece to explode. BISQUEWARE When the pot is dry and there are enough to completely fill the kiln they are fired to approximately 1900 degrees over the course of twelve hours and allowed to cool for another twelve hours. At this point they will be porous and light and have changed in color due to changes in the clay from firing. The clay will resemble a terracotta flowerpot in it’s ability to absorb water which is needed for the next step– glazing. GLAZEWARE Glazes are the consistency of thick cream and made up of water and clay or elements like silica which will turn to colored glass in the kiln. Lead is no longer used in glaze recipes due to toxicity. Wax is applied with a sponge to the bottom of each pot so no glaze deposits there and then each pot is dipped in or painted with the desired glaze(s). The pots are then stacked in the kiln , fired to approximately 2300 degree, and allowed to cool. This process takes 24 hours to complete. When the kiln has cooled the lid is opened and usually there is much rejoicing at the beautiful pieces that are removed. Usually these stages are all happening simultaneously. For instance while firing a bisque kiln I may be decorating greenware and setting it out to dry. So on any day the shelves are filled with pottery in various stages of completion. 
This pic is of two pieces that touched in the kiln and now are permanently stuck together. In school I wanted every chance I could get to learn more about the process so I'd help load kilns. This consists of carefully placing pots on shelves and then stacking the shelves on stilts. It's an intense process as you want to use every available space and yet no glazed portion of a pot can touch anything else or the above happens. One time in my haste and inexperience I forgot the spacing stilts on the lower rear shelves. When the kiln reached temperature and the clay was almost molten all the shelves sagged backward causing all the pots to shift and slide together. I still shudder to think of all the first pots those beginning students had turned over to be fired only to have them returned warped and cracked and stuck to one another. The tiny little goblet above was made by me and the larger vessel by my teacher Sister D. I received this piece as a memory and a lesson. |
Live as if you have all the time in the world: no
hurry, like you'll never die - also live with the passion like you know you'll
die tomorrow (paraphrase from)
Michelle Holzapfel- woodworker HE WHO LAUGHS- LASTS!!! |