Simon Leach's Pottery Handbook by Simon Leach - STC

SIMON LEACH and

BRUCE DEHNERT Photography by

JARED FLOOD and

BRUCE DEHNERT

STC Craft | A Melanie Falick Book S T E WA R T, TA B O R I & C H A N G • N E W Y O R K

contents I N T R O D U C T I O N 000 Chapter 1: G E T T I N G S TA R T E D 000

Setting Up the Studio Clays and Clay Bodies Handling Clay

000 000 000

Chapter 2 : T H R O W I N G 000

The Cylinder

Cylinder Variations Dishes

000 000 000

Chapter 3 : T R I M M I N G 000 Chapter 4 : A S S E M B L I N G 000 Chapter 5 : D E C O R AT I N G A N D G L A Z I N G 000

Decorative Techniques Glazes

000 000

Chapter 6 : F I R I N G 000

Kilns and Firing

000

A P P E N D I X 000

Engobe and Glaze Recipes

Glossary of Ceramic Terms Acknowledgments Index

000 000 000 000

handling clay T

he physical starting point of creating pottery on a potter’s wheel is the clay. Whether you use a commercial mix or dig your own, clay requires preparation before you put your heart and hands to the challenge of making pots.

Normally I prepare my clay using the spiral kneading technique (there are lots of kneading styles). If I’m using reclaimed clay or the clay is lumpy, I might wedge it first.

Wedging takes its name from the shape the clay acquires during the process, and it helps to break down the hard lumpy pieces because you cut through the block of clay

many times and slam it down, one piece into the other, on the wedging table.

There are three objectives to wedging and kneading: to compress the clay particles, to blend the individual ingredients well, and to remove air pockets. Compression makes for a tighter clay body so that your pots will dry and fire with less chance of developing cracks or air bubbles.

(Well-compressed clay helps a pot to be thrown more uniformly.) Fresh commercial clay has been “de-aired” by a machine called a vacuum pugmill, so it’s unlikely to have air pockets. Instead, care must be taken during wedging and kneading not to introduce them to the clay by folding the clay over onto itself, as if you were kneading dough. If air pockets aren’t worked out of the clay, they can disrupt the throwing process itself. Pockets also become spaces for steam to gather during the firing process, which increases the possibility of a blowout. It’s easy to determine if your kneading technique needs improvement by examining a cross-section of the clay.

Once you’re at the wheel, you don’t want to have to stop to wedge and knead more clay for your next pot.

This amount will be enough to make several pots in one sitting. Start with dry hands. Your work surface is important, but potters vary in their preferences. I prefer a tabletop made of marine plywood that has been lightly sanded smooth. This type of plywood is durable, cleans easily, and its surface is slightly porous, which will release the clay as you work with it.

For both wedging and kneading, you’ll need:

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a sturdy table a wire cutoff tool 8 to 10 pounds (4 to 5 kgms) of clay a digital or analog scale

G E T T I N G

S T A R T E D

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C H A P T E R

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throwing cylindrical forms 48

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C O N C AV E C Y L I N D E R You should be able to competently throw a basic cylinder before you try to make a shapely vase or a bellied cider jug. Before you start to throw, give some thought to what you want the pot’s proportions to be (for example, how wide the rim should be in relation to the base and the narrowest part of its waist). ] Center the clay. Using your right thumb and bracing with your left hand, define the base width and tidy it up before you open it. Open the clay lump, with a floor depth of ¼ inch (6mm). ] Spread the floor of the clay lump so that it’s 1 inch (2.5cm) wider than the original width. Collar the lip of the pot gradually, so its rim is narrower than its base. ] Make two pulls, so that the wall is the same thickness as the floor. Pay particular attention to keeping the form conical by applying greater pressure with the outside fingers and less outward pressure from the left hand (1).

] Halfway up the third pull, gradually switch the source of your pressure. This added pressure, plus holding the fingers of your right hand fingers (outside the pot) at a level below your left ones (inside the pot), ensures a concave shape (2) . ] By now you’ve established the basic foundation of a cylinder. The next step is to collar the form more assertively.

With the wheel turning moderately slow, position your hands as near to the base as possible (3) . Make light contact with all six fingers (4) . Exert equal pressure with all your fingers as you slowly bring them up (5) . ] When you reach the halfway point, gradually release your pressure (6) . Keep your eye on the pot’s profile and use your fingers to adjust the proportions of the form.

When you are satisfied with the rim, let the wheel make several revolutions before slowly releasing your fingers from the clay. Finish and remove the pot as shown in the basic cylinder instructions on pages 000.

C O N C A V E

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T H R O W I N G

C Y L I N D R I C A L

C Y L I N D E R

F O R M S

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