how Stella NC Works pottery is made
1. Clay found in nature can be processed and used. But usually a potter will buy clay that is already processed by a company. In the US, wet clay is usually sold in 25-pound bags, sometimes 2 bags to a box.
2. I use a wire to cut a chunk off to use.
3. I "wedge" the chunk to evenly distribute moisture and to loosen the clay up.
4. Forming the clay can be done by hand-building or wheel-throwing. Handbuilding is alot like playing with Playdoh: squishing coils, using a rolling pin, etc. To throw on the wheel, I slap a wedged chunk of clay into a ball, slam it onto a "bat" on top of the wheel, coat it with water for lubrication, and use a combination of pushing and pulling the clay to center the lump, open a hole, pull up walls, and shape them. Depending on what I am making, I often use a plastic shape called a "rib" to shape walls and scrape excess moisture away. I clean up the rim and walls with a sponge, cut an indent along the bottom edge with a wood knife, use a wire to cut the clay from the bat, and set it aside to dry.
5. Once it has dried slightly so the form is more solid, the item is flipped over to "trim" the bottom - depending on the function, there are various ways to clean up the bottom by smoothing it or creating a foot ring, and marking it with my identification chop.
6. At various stages of drying, I decorate - sometimes I carve, sometimes press leaves into the clay, sometimes add handles or other details.
7. Depending on clay thickness, humidity, and other factors, something like a mug usually takes about 2 weeks to dry completely. It is important that moisture evaporates, because if it reaches boiling temperature in the kiln, the instant conversion to steam causes it to expand rapidly, which blows apart the surrounding clay.
8. Loading the kiln, I inspect each piece for cracks and use a wet sponge to smooth rough areas. Until clay items are fired, they are called "greenware" - if a greenware item is not up to standards, the clay can be recycled at this stage, but not after it is fired.
9. Depending on the desired outcome, underglaze can be applied to greenware. This is when I use the white underglaze to paint ferns that will subtly show up later under white glaze.
10. I bisque fire to cone 04 (approximately 1940 degrees F). The firing itself takes about 11 hours, and then the kiln takes about 24 hours to cool enough to open. Some people glaze their pieces once the clay is dry and only fire once. I fire most things twice because of the decorative processes I prefer to use in between the two firings.
11. At this stage, clay items are called "bisqueware" - this is the stage I do most of my decoration. I paint with underglace, rub underglaze washes into crevices, draw with underglaze pencils, and depending on the glaze and the desired effect I either brush or dip the glazes onto each piece. This is also when I sign my name on the bottom.
12. I usually glaze fire to cone 6 (approximately 2232 degrees F) (for some glaze effects, I fire instead to cone 5 or 7). The firing itself takes a little more than 8 hours, and then the kiln takes about 24 hours to cool enough to open.
13. Sometimes a third firing is used for overglazes, like gold or mother-of-pearl luster.
14. I inspect each piece closely for bubbles in the glaze or cracks. Cracks cause a piece to be rejected. Bubbles can sometimes be healed by grinding, reapplying glaze, and refiring.
15. I sand the bottom of each piece so that it doesn't scratch furniture. It's also nicer to touch smooth bottoms :)
16. I test all new glaze combinations to make sure they will survive thermal shock by pouring boiling water into the room-temperature piece.
17. Once the piece is completed, it is priced and labeled for local sale, photographed, measured, and described for online sale, and/or packaged for shipping.
**RECAP: Cut a chunk of clay. Wedge. Form the clay. Clean up the form. Trim the bottom. Decorate. Let it dry. Inspect and clean up the form. Underglaze. Load the kiln with greenware. Bisque fire. Wait to cool. Unload the kiln. Underglaze. Glaze. Sign the bottom. Load the kiln with bisqueware. Glaze fire. Wait to cool. Unload the kiln. Sometimes overglaze/luster and third firing. Inspect. Sometimes reglaze and refire. Sand bottoms. Test for thermal shock. Price/label/photo/describe, package and ship.
**OTHER TASKS I have to do that are not part of making an individual piece:
Paint shelf wash onto kiln shelves so that spilled glaze doesn't stick. Scrape and grind old wash and spilled glaze, and repaint.
Kiln maintenance. Replace elements (the wires that make the heat) and other parts like the thermocouple and relays.
Clean the workshop. I do this in a mask because silica dust never leaves your lungs. It is important to clean often to keep dust at a minimum.
Mix glazes. I buy some of my glazes as powders, and some need to have ingredients measured and mixed, while others come premixed and I just have to add water, let it sit for 24 hours to fully hydrate, mix and screen (filter), and test.
Reclaim clay. Whenever greenware is scrapped, I put it into a bucket. Once I accumulate a bunch, I break it into small pieces, add water, mix thoroughly, let it dry, wedge, and put it in a bag as new clay.
Clean glaze brushes.
Create molds by pouring and/or carving plaster or clay. Carve stamps. Create tools.
Make test tiles for testing glazes and glaze combinations.