Saturday, September 14, 2013

@A Lifetime With Clay

      At seventeen, I signed up for a  pottery class, unaware at the time, that this would become a long term passion of mine. The class was located in a local potter's basement with work tables, wedging boards, slop buckets and a kiln. Every week I would slam, wedge, roll, pinch, shape, attach, and create some pretty amazing bowls, plates, vases, and sculptures. This of course, did not happen in one lesson. There are many steps and skills required to produce attractive pottery, but when that first finished glazed pot comes out of the kiln, there is a huge sense of accomplishment and pride, and you also have your very first Christmas gift.
     I think I will start this blog by talking about the types of clay and equipment, and then move on to
methods of creating pottery with specific lessons.
     Earthenware clay is the easiest clay to work with when you begin. It has a smooth texture and is quite pliable when creating forms. The clay is white, cream, or terracotta (red) after firing. It can be purchased in Canada from Pottery Supply House in Oakville, Ontario and they ship UPS. Their website is www.pshcanada.com  You can purchase a 20 Kg. box of earthenware clay for under $25.00 + shipping. They sell various tool kits to work the clay, but you can also use several kitchen utensils that work quite well and produce good results.
     The beauty of earthenware clay is that it fires at a lower temperature in the first firing (from green ware to bisque) and in the glaze firing when it is completed. I'll talk about firing temperatures later after the first piece of greenware is ready to fire. I should first explain about the term "greenware".
After your first piece is completed and you are happy with it, carefully place it on a drying shelf and cover it loosely with a plastic bag. This allows it to dry out slowly and evenly, and be less likely to crack. After a few days, remove the bag and let it air dry for several more days. It should be bone dry and is now called greenware. If you pick it up, carefully lift it with both hands underneath. Don't just grab one side to lift it, as you may just get a piece of it, and this broken pot is difficult to repair and never quite right. There are a few tips below before you let your pot dry.
After you build your first pot, you might want to remove some of the clay to make it more appealing, (less lop-sided)and you could finish the final details in several ways:
  •  by pealing off excess clay bumps with a sculpture tool, peeler, or knife. 
  •  by smoothing the surface with a damp sponge until you are satisfied with the results. (Do not use sandpaper to dry sand the pot because the silica dust in the clay will disperse into the air around you)...not good to breathe in.
  • turn the pot upside down and scratch your name or initials and date into the flat bottom of the pot with a pick tool or an awl.  If you don't have either one, try a pencil or a pen.
  • by adding texture to the pot when it is leather hard by scratching or sculpting a design into its exterior clay finish, or by adding texture with small bits of leftover clay and forming a pattern or design on the outside of the pot.

 
 


Lesson #1  Hand Building with the Pinch Pot Method
Oh, I should tell you first about the work board. You'll need a square piece of wood, about 2 feet by 2 feet. Cover the wooden board with canvas, linen, or burlap, pulling it tightly around the board, folding the corners, and stapling the ends to the back. A staple gun is best. Burlap is great when we do the slab method, as it creates a texture on the clay, but a smooth cloth is better when we do the coil method. I use a smooth fabric and just place burlap over it when needed. You might want to make two work boards and interchange them. You also should always have 2 small containers (empty yogurt cups work well), one for water and one for slurry.
With a thin wire, slice off a block of clay about the size of a pound of butter. Seal up your big block of clay tightly with a twist tie to keep it moist for your next project. You won't need a pound of clay for this project, but you can save the rest in a baggie. Always store your excess clay in a sealed baggie when you are not working on it. Occasionally, your new clay may be quite sticky when you slice it from the bag. If this happens, shake a little baby powder on your work board and on the clay. And, it smells great!
Slice your pound of clay in half and cut off a corner of the leftover half before you seal it in the baggie. Mix the corner piece of clay with a few drops of water in a yogurt cup. A popsicle stick works well to stir the slurry into a smooth thick paste. This slurry will be used to attach pieces of clay, fix cracks, or attach surface texture and designs. If the slurry dries out at a later time, you can refresh it with a few more drops of water. As long as the clay has not been fired, you can rework it.
Okay, back to our 1/2 pound of clay. Form the clay into a ball shape in your hands.
Step 1- You must slam the clay several times, to remove air bubbles, onto a clean basement floor, a sidewalk, patio block, or a premade wedging table. I'll discuss this later when I talk about equipment.
You will then wedge the ball of clay on your board or wedging table. This is somewhat like kneading bread dough. Do this several times in different directions and check the inside with a wire. You should not see any air bubbles. If you do, repeat. If not, slam the 2 pieces back into a ball and reshape it with your hands. Check out this YouTube video.
http://youtu.be/yUlWD3R3eE4

Step 2-With the clay in a ball shape again, poke your thumb in and push it far into the centre of the ball, past 1/2 way, but not to the bottom. Make sure your fingernails are quite short or you will have cut marks inside the clay. Then, pinch the clay between your thumb and fingers to spread out the center hole, and move the clay ball in a circle as you pinch. Try to shape the small bowl as you go by pinching any thicker areas to make the pot uniform.
Step 3-The bottom of the pot may not be flat, so you can hold the pot level over your board and drop it to flatten for the base. A few small drops again should even it up to form a flat level base. You can also push some of the excess clay inside the base out toward the side and then pinch again to even out the walls of the pot. You want to achieve about a 1/4 inch thickness of clay for the base and walls, Pots that are too thick have a better chance of exploding in the kiln. The pinch pot in the photo above was one I made with red terracotta clay. I added a few coils to form it up to the rim, but I'll explain those when we do the coil method in another lesson.
Step 4- Any cracks that appear can usually be smoothed out with your finger, but stubborn ones might need a tiny bit of slurry applied and worked in with your finger. Keep working on the shape and top of the pot until you are happy with it. If the top rim is uneven, you can use a wire to slice off any bumps, or try a small knife or sculpture tool until you think it is level. The important thing here is that you have to be happy with it. Maybe you like the lop-sided edge and stretch and form it into a spout. Whatever you decide, it has to be appealing to you. It is your creation to have fun with.
Step5-When you are happy with the basic shape, carefully lift the pot and move it to a shelf to partially dry (usually overnight). Cover it loosely with a plastic grocery bag until it is leather hard. Cover your slurry so it stays fresh. Clean any tools and wipe your work board with a damp sponge.
For all projects, you should wash your hands, tools, and sponges over an empty bucket in your laundry sink, so that clay slurry, clay bits, and clay water goes into the bucket, not directly into the drain. You don't want to have to call Mr. Roto-Rooter to unclog your sewer pipes, so this is vital. After about a week, the clay will settle in the bucket, and you can pour off the clear water into the drain and save the slurry to rework later. Once you start trying various clay types or colours, make sure you have separate buckets for clean-up and label them with clay types (white earthenware, black stoneware, terracotta).
Step 6-Return your leather hard pot to your work board if you want to add texture or surface design. If you have a small lazy Susan or banding wheel, this makes life much easier. If you don't, you can still move your piece manually. Find kitchen tools that you could use to carve into the leathery clay to make grooves or wavy lines around the outside of the pot. Remember that the clay is more fragile than when you worked it, so go carefully. If you want to add surface design, like a flower or graphic, roll a tiny bit of clay from your baggie, shape it into say a diamond shape and scratch up the underside of it with a tiny pin tool and scratch up the surface of the pot as well where you are going to attach the diamond shape. Spread a tiny amount of your slurry onto both scratched areas and press on your design. The slurry makes the design stick, so don't forget this step. Add as many as you like or combine surface attachments with carved out grooves. Stop when you are happy with your work.
Step 7-Don't forget to sign your masterpiece! Turn the finished pot over, and using a pin tool, needle, or old pen, carve in your name (usually more difficult) or your initials (my choice) and scratch in the date. In a later lesson, we will make stamps for your own personal  signature or design stamps for texture application.
Step 8-Return your finished pot to the drying shelf and leave it there to completely dry until it is bone dry. This could be a week or even longer for thicker pots. Don't pick it up to admire it when it is bone dry! This is the most fragile stage for breakage, so when you are ready to have it fired, carefully lift your pot with both hands and place it in a shredded paper box and take it to a kiln. As a beginning potter, you probably won't have access to a kiln, so seek one out. Many ceramic stores, who sell molded pieces of green ware, fire the pieces for their customers, so if you are using earthenware clay, your pieces could be fired at the same temperature, and in the same load as their ceramic pieces. They will probably charge you a few dollars for the firing and again charge for your later glaze firing. If there is a pottery studio in your area, you might ask the owner to fire for you, or a school that gives lessons might also take your pieces to fire. This can be a problem to find, and is the reason why most potters end up buying a kiln.
See you next week for Lesson 2!
Nancy
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1 comment:

  1. I used to do pottery back in high school. It was very relaxing and enjoyable. What a great story! I am going to read this over again tonight and see what I can do. Perhaps I will be able to learn enough to try this with the kids at school.

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