6713442 ceramic-arts-handbook

Ceramic Arts Handbook

by Vince Pitelka
www.ceramicartshandbook.com | Copyright © 2001, 2007 The American Ceramic Society

Ta b l e o f C o n t e n t s

Preface.......................................................................................... 1
1 Clay and Claybodies. ............................................................. 3
.
The Nature of Clay................................................................................. 3
Claybodies .............................................................................................. 4
2 Handbuilding......................................................................... 5
.
Wedging the Clay.................................................................................. 6
Handbuilding: General Guidelines
and Suggestions.................................................................................. 6
Making Pinch Forms.............................................................................. 9
Coil Construction................................................................................ 11
Slab Construction. .............................................................................. 14
.
Making Tiles........................................................................................ 17
3 Throwing.............................................................................. 19
Critical Points in Throwing................................................................. 19
Skill Development with Cylinders...................................................... 21
Throwing Bowls.................................................................................. 22
Drying Your Pots................................................................................. 26
Finishing the Bottoms of Your Pots................................................... 27
4 Surface Decoration on Greenware..................................... 29
.
Decorative Effects during Forming.................................................... 29
Impressed Decoration. ....................................................................... 29
.
Subtractive Methods. ......................................................................... 31
.
Additive Methods............................................................................... 32
.
5 Glazes and Glazing.............................................................. 33
Introduction to Glazing...................................................................... 33
Glaze-Firing Ranges............................................................................ 34
Glazing Methods. ............................................................................... 34
.
Glaze Faults......................................................................................... 36
6 Kilns and Firing.................................................................... 38
General Kiln and Firing Practices....................................................... 38
Preparing and Loading Kilns.............................................................. 39
Determining Appropriate Firing and
Cooling Ramps. ................................................................................ 41
.
Kiln Firing Chart.................................................................................. 43
7 Studio Safety........................................................................ 44
Studio Safety Checklist....................................................................... 44
Toxic and Hazardous Materials.......................................................... 45
Dust/Dirt Management...................................................................... 45
Skin Care ............................................................................................. 45
Equipment Safety................................................................................ 46

www.ceramicartshandbook.com | Copyright © 2001, 2007 The American Ceramic Society |

Preface

This Ceramic Arts Handbook is an abridged version of Vince Pitelka’s best
selling Clay: A Studio Handbook (The American Ceramic Society, 2001). His
book has sold thousands of copies and is used both as a textbook and refer-
ence resource in thousands of ceramics studios in art schools, community
art centers, colleges, universities, and homes. While the book authoritatively
explores each topic in great detail, we’ve extracted some of the basic essen-
tials you need to get you started on your clay adventure.

In his introduction, Vince writes “Through 30 years of experience as a
studio potter, welder/fabricator/mechanic, and university educator, I have
been collecting and disseminating information about ceramics. This book
is a compilation of what I feel will be most valuable to ceramics students,
studio artists, and educators, regardless of the particular direction of their
ceramic work or teaching. I hope it will provide a convenient reference to
help you through most of the steps in skill development, studio setup, and
operations. It is my intent to offer answers and stimulate ideas.”

Working in clay is one of the most rewarding activities. It’s suitable for
all age groups and personalities and provides challenges for every skill level.
We believe that this Handbook will provide you with a deeper understand-
ing and appreciation of this medium, and hope that you’ll be able to spend
many joyful hours ahead with your hands in clay.

Bill Jones
Ceramic Arts Book Manager

Clay: A Studio Handbook
by Vince Pitelka
The American Ceramic Society, 2001


Clay and Claybodies
Chapter 1

The Nature of Clay
We who work and play in clay have chosen well. Clay is among the
most abundant and inexpensive materials on earth. The natural processes
that weather and decay igneous rocks have been generous in providing
us with extensive clay deposits in a variety of forms. Clay is abundantly
available almost everywhere on earth, awaiting our need, often requiring
little processing.
Clay is a remarkable material for so many reasons. There is no other art
or craft material that has the versatility and possibility of clay. We can cast
it, throw it, extrude it, model it, roll it, pinch it, press it, slump it, stamp
it, pull it, and push it. We can use it to create any form or shape, tiny or
monumental, organic or rectilinear, thin and fragile, or thick and heavy. It
is the most malleable and forgiving of art materials. It asks little of us, but
with commitment and respect on our part, it rewards us generously.
When subjected to a simple firing process, clay is transformed to hard,
impermeable stone, and what was once so malleable and impermanent
might now remain stable and unchanged for millennia. As if the mere
workability and fired permanence of clay were not enough, we can also
apply an unending variety of mineral coatings that fuse into glassy glaze
surfaces of unlimited color and texture. When you place a lump of clay
in anyone’s hand, the response is automatic. The hand closes and squeezes
the clay, and a unique sculptural form is produced, subtly different from
any other before. Few of us stop at that point, for the clay encourages us
to apply different forces, responding to every push and pull. Until the clay
begins to stiffen, there are no rules, and no externally imposed finality. We
can undo what we have done, and we can immediately return any form
or shape to a simple lump and begin anew.
We do not know what we can do until we find out what we cannot do,
and in order to fully discover the possibilities, we must take chances and
experience lots of failure and mistakes. When in doubt, make something.
Never allow frustration or failure to drive you from this medium.
Do not ever stop experimenting and exploring. Do not be satisfied with
a single direction in your work. Do not become smug with any aspect of
the medium, no matter how well you think you know it. The clay will
catch you off guard and will throw you for a loop every time. But as long
as you maintain a spirit of discovery and curiosity, the clay will reward
you frequently and generously.


Clay and Claybodies • Chapter 1

What Is Clay? and bisque strength, and yet it mini- Porcelain claybodies include
Clay results from the natural mizes the water content and result- gritless high-fire bodies that fire
decomposition of certain igneous ing shrinkage. close to pure white. Under cer-
rocks—primarily granite and feld- tain circumstances, fired porce-
spar. The end result of the decom- Claybodies lain can be translucent. True bone
position of granite and feldspar pro- Claybodies are mixtures of clay china (traditional translucent por-
duces microscopic flat clay crystals and other materials designed to celain) is so-titled due to the
called platelets. accomplish specific goals like addition of bone ash (calcium
When microscopic clay platelets plasticity in throwing, stability in phosphate). Bone china bodies are
are wet, they tend to stick together large-scale work, thermal shock very prone to warpage unless fired
and slide smoothly against one resistance, dry and fired strength, on flat shelves with no hot spots
another. The most plastic clays are or vitrification and density. in the firing. Actually, any reason-
those with the smallest particle size. Earthenware claybodies remain ably well-fluxed cone 10 porcelain
Different clays behave differently porous at low-fire, and yet at thrown very thin will give some
depending on the range and dis- higher temperatures will likely translucence without the disad-
tribution of particle size and the deform and bloat before vitrifica- vantages of bone china.
p
resence of non-clay contaminants, tion. Traditional earthenware bod- Stoneware claybodies use natural
primarily organic materials and ies are usually red or buff, a blend stoneware clay and/or fireclay as
nonplastic minerals. of iron-rich surface clay plus sand a base, with additions of ball clay,
or grog to give structure and often kaolin, flint, fluxes, and/or grog or
How Does Particle Size with fireclay or stoneware clay to sand. Whiteness is rarely an issue,
Affect Drying and Firing? increase firing temperature and so the materials are selected for
The size and shape of clay par- reduce the chances of deformation desirable performance in form-
ticles help determine plasticity, but and bloating. Modern low-fire ing and firing, regardless of color.
they also have profound effects in bodies are often white, composed Natural stoneware clays and plastic
drying and firing the clay. The evap- of 50-50 ball clay and talc, and are fireclays with the addition of ball
oration of the water layer existing
actually very similar to ones used clay produce an extremely plastic
between each particle in the plastic
by the Egyptians 5000 years ago. throwing body. Adding sand or
state is what causes drying shrink-
A low-temperature firing pro- grog gives tooth or structure in the
age. The finer the particle size, the
cess does not necessarily mean plastic state and reduces slumping
more water layers are present, and
an earthenware or whiteware during throwing or handbuilding,
therefore the greater the water con-
clay—the raku and bonfire pro- allows thinner, taller wares with
tent, and the greater the drying
cesses often use highly refractory greater horizontal extension, and
shrinkage. But at the same time,
stoneware bodies that are simply reduces drying shrinkage. •
the finer the particle size, the more
contact points between particles in underfired at low-fire tempera-
the dry state, which gives greater tures and are therefore very porous
dry strength in greenware and more and open, giving high thermal
bonding surfaces in the early stages shock resistance. Low firing is
of the firing. The ideal condition is especially appropriate for large
to have a mixture of sizes of clay par- sculptural work, as there is little
ticles. This creates as much contact or no shrinkage in low firing, and
surface as possible between particles, common problems with cracking
giving good plasticity, dry strength, and warpage are minimized.


Handbuilding
Chapter 2

With handbuilding, the full scope of sculptural form and expression is
available to the potter and the sculptor. It offers innumerable possibilities in
structure and surface that are impossible or impractical on the wheel. With
handbuilding processes, one can construct almost any imaginable shape.
These processes are divided into three main categories: pinch, coil, and slab
construction. Pinch and coil construction are the prevalent forming meth-
ods in all ancient and tribal cultures. Slab construction was widely used
in Meso-American pre-Columbian cultures, but otherwise is rarely found
until modern times. Pinch construction is by far the simplest of these pro-
cesses and provides the ideal introduction to all other ceramics construction
methods. Pinch forms are usually confined to less than six inches in diam-
eter, although there are exceptions to this. Pinch forms can be made either
very thin and delicate or thick and substantial. There is something quite
remarkable about an eggshell-thin pinched form, sanded and burnished,
and blackware bonfired to a satin black luster.
Coil constructed forms can take almost any shape imaginable. Coiling is
the only method where novices can quickly learn to make very large ves-
sels or sculpture, and the experience can rapidly increase their confidence
in clayworking. Coiling is especially appropriate for organic forms, large
volumetric vessels, and figurative sculpture.
Clay slabs can be worked in either the soft-slab or stiff-slab method,
indicating the condition of the slab while it is being worked. The soft-
slab method is appropriate for slumped, draped, or soft-formed vessels, for
clay masks, or for draping onto forms to make components to be stiffened
and assembled. It is also ideal for making a wide variety of curvilinear and
organic forms. The stiff slab technique is more appropriate for rectilinear
and architectural forms, although the two approaches can be combined.
Even for hard-edged geometric forms, many sculptors and vessel makers
slump-mold curved components and assemble them leather-hard along
with flat, stiff-slab components.


Handbuilding • Chapter 2

Wedging the Clay homogenizing any irregularities in Forming Method: Use the
The wedging process is important composition or moisture content, method appropriate for the forms
in all ceramic construction tech- and more importantly, eliminating you wish to make—for organic
niques, as poorly wedged clay sim- air bubbles. Remember not to push shapes use coil, pinch, or soft slab,
ply does not respond well. Wedging down from above, flattening the for geometric shapes use coil or
mixes and homogenizes the clay and lump, and be sure not to push so stiff slab.
eliminates air bubbles. Do not ever hard on each stroke that you smear Awareness of Surface Effects:
settle for clay that is too wet or too the ball out too flat, because when With an appropriate forming method
dry—it simply isn’t worth it. With you stand it up and push again it and sensitivity to the surface created
clay that is too wet it is a simple will fold over on itself, trapping air during initial construction, subse-
matter to wedge it on a dry plaster instead of eliminating it. Each push quent surface finishing may not be
slab, or to slice it, stand the slices should just smear the bottom of the necessary. The forming or assembly
vertically and allow them to stiffen lump over a little, without ever trap- process itself can often create patterns
up. Any clay that is too dry can be ping more air in the clay. or marks that are very pleasing.
sliced, wetted down, and left in a Generally a minute or so of wedg- Concentration of Pressure
bag or barrel overnight to absorb ing is enough, but, if you are blend- Points: All stages of manipulating
the moisture. If you stiffen or soften ing different clays or working dry the clay depend on concentration
your clay by these methods, be sure material into overly wet clay, it may of pressure points, giving you much
to wedge it very thoroughly before take considerably more wedging. If greater control than with a broad
using it. the clay lump begins to elongate to application of pressure over a large
When first learning to wedge, either side, slap your palms against it area. EVERY part of your hand is
cylinder wedging is usually the easi- to narrow it. useful. Remember that for every
est approach to master. Start with a action there is a reaction. Keep in
ball of clay that you can comfortably Handbuilding: mind the consequences of every
stretch your fingers around (like a General Guidelines type of pressure that you apply to
large orange). Set the ball on a flat and Suggestions the clay.
surface, preferably a canvas-covered The following guidelines and sug- Wall Thickness: Make pieces only
table. Hold both hands as you would gestions apply to all clayworking, as thick as is necessary. Extra thick-
to shake hands with someone, and but especially to handbuilding. If ness does not necessarily increase
grab the ball firmly with your hands you familiarize yourself thoroughly structural integrity. In tall pieces you
wrapped around either side, as indi- with these guidelines, the learning may wish to make the lower walls
cated in Fig. 2.1. Applying pressure curve will be accelerated. slightly thicker, but otherwise main-
downwards against the table, push Commanding Approach: Clay tain uniform thickness. For most
the ball away from you slightly, mov- appreciates a vigorous, command- sculpture and vessels, even a very
ing it two or three inches so that the ing approach with an economy of large piece should not be more than
bottom smears forcibly against the motion. Whatever you do, do it for I to 1 thick anywhere.
table. Roll the ball back up towards a specific reason. With an aggres- Base Support and Bottom:
you (standing it up on the smeared sive, adventurous approach, you will Always construct large forms on a
“extension”), grab again on either learn much faster than with a weak, sturdy movable board, with several
side as before, and push down and tentative approach. layers of newspaper under the clay
away as before. Repeat this at least Clay Consistency: Always start to prevent sticking and to allow for
20 times for each lump of clay. with well-wedged clay of an appro- contraction of the piece during dry-
This process creates a spiral twist- priate stiffness or softness for the ing shrinkage. On coil or slab work,
ing and stretching within the lump, desired project. always build on top of a bottom slab



of clay. Whenever possible, have
Figure 2.1 Cylinder Wedging a single continuous base that
supports all parts of a piece. For
example, if you are building an
animal form with delicate legs,
incorporate a base as part of the
piece, thereby supporting and
protecting the legs.
Closed Spaces: Never create
completely closed spaces, as they
will trap steam pressure and may
explode in the kiln. Always make
breather holes. Tiny pinholes are
adequate, but make several in case
Place hands on either side of the lump in Lean into the lump. one becomes clogged. Whenever
handshaking position.
possible, ALWAYS leave larger
breather holes. Never apply addi-
tions or appliques in such a way
that air is trapped beneath them.
Joining: Always join clay
aggressively and firmly in a way
that is appropriate for the con-
sistency of the clay. NEVER
press clay straight together with-
out proper preparation, as this
will result in the alignment of
particles in a fracture plane.
Soft clay may be joined with-
Continue leaning into the lump, smear- Roll the top of the lump directly up
ing the lower portion against the wedg- towards you and grasp the sides. out scoring or slurry, especially
ing table. in coil construction, as long as
the pieces are smeared thor-
oughly together, blending the
seams inside and out to ensure
thorough interlocking of the
particles. In all other circum-
stances, when joining parts or
adding soft clay or appliques to
a surface, score thoroughly with
a fork or toothed rib, be sure
to use enough slurry to force
out all air bubbles, and press the
parts in place firmly to eject all
Lean into the lump again, roll it back C
ontinue until the lump is well blended
excess slurry. With leather-hard
towards you, and repeat. and shows this appearance.
clay, always fit the pieces well,



score thoroughly, use a generous metal tool, the surface feels scratchy, the clay’s ability to support itself.
amount of slurry, and immediately and the displaced material falls away With large pieces, cover the surfaces
join the pieces with firm pressure. freely as small particles. Many peo- where more parts are to be joined,
In joining component parts or slabs, ple like to carve the clay at this and allow the rest of the piece to
whenever possible score the inside stage, although a point between stiffen before continuing (or accel-
of the joint and press in a small coil medium and hard leather-hard is erate stiffening with a hair dryer or
of soft clay along the seam. Ideally, usually more desirable. This stage is propane torch).
pieces to be joined together should appropriate for thin surface paint- Structure: At all stages, consider
be the same consistency and stiffness. ing, but not for thick slip techniques the structural integrity of the clay
However, this is not always possible, like slip-trailing. Once the clay has (in both wet and dry stages) and its
and when joining pieces of dissimilar begun to bleach (lighten in color ability to support the upper por-
moisture content, cover the assem- from drying) it has passed beyond tions of the piece. With large sculp-
bled form and allow the moisture the leather-hard stages. tural forms, cross brace the interior.
content to equalize before allowing Assembly: Regardless of forming Always support horizontal protru-
the form to dry. Do not attempt to method, it is often advantageous sions or extensions with a tempo-
join pieces that have dried beyond to build large pieces in sections to rary prop until they are firm enough
medium leather-hard, except when be joined when soft or medium to support themselves. Do not over-
using paper clay techniques. leather-hard or to be fired separately. look the possibility of using wadded
Stages of Leather-Hard: After the fire, they may be stacked newspaper as an interior support to
Soft leather-hard is the stage loose, assembled on an armature, or maintain the shape of closed forms
where you can easily pick up a small cemented together with epoxy or or to support relief forms such as
or medium-size piece without dis- silicone adhesive. masks. It may be left in place and
torting it, but the surface is still a bit Avoid Using Water: Do not use will burn away in the firing.
tacky. When trimmed with a trim- water to smooth or finish a piece as Controlled Drying: Always care-
ming tool, the trimmings tend to you work on it—it will just soften fully control the rate and degree
ball up and stick under the tool, and the clay, removing structural integ- of drying. When time constraints
the form is easily distorted or dam- rity and making it harder to work. demand it, large pieces may be stiff-
aged. This is an ideal stage for joining Do not use water in place of slurry ened with a heat gun, hair dryer,
parts, as long as they can be handled when joining pieces, except perhaps or propane torch before continu-
without serious damage. with very soft clay. Otherwise, it ing with construction, but this can
Medium leather-hard is the stage may just lubricate the clay surface result in uneven stresses on the clay.
when all surface tackiness is gone, and encourage the formation of When necessary during construc-
and plastic clay will not stick easily fracture planes. You may, of course, tion, pieces may be moistened with
when pressed against the clay. When use water (applied with a sponge, a spray bottle to retard drying. Any
the surface is incised with a model- brush, or spray bottle) to slow down large pieces to be left covered with
ing tool, the displaced clay rises in the drying process whenever it is plastic should first be draped with
attached ridges along the groove. proceeding too rapidly. a large cloth (old towels or bed
When trimmed, the trimmings fall Working in Stages: Each part sheet) to absorb and dissipate mois-
freely away, and will not stick to the of the process should be done at ture. Otherwise, condensation under
surface or the trimming tool. the appropriate stage of softness or the plastic can run back onto the
Hard leather-hard is the stage hardness. When constructing large piece in concentrated areas, possibly
where the color is still “damp,” but shapes consider the clay’s ability causing collapse. Large complicated
the clay is too stiff for easy trimming. to support higher sections. Do not pieces should be kept covered and
When incised with a wooden or attempt to keep working beyond allowed to dry very slowly. Small



parts that protrude from a form thickness and the strength and resil- and thinning only the clay in the
must be protected from quick dry- iency of the clay. Through pinch- lower portion of the pot, without
ing, especially if they attach in two ing, we become extremely sensitive expanding the opening and the
or more separate places. The easiest to the use of touch rather than upper rim.
solution to this problem is to coat sight in determining and control- When you have made one pass
those parts with wax resist. This will ling ceramic form. With practice, around the bottom, or when the
cause the moisture to wick into the pinch construction can become area you are pinching has reached
body of the piece, so that everything a viable method of creating small a suitable thickness (no more than
dries at the same rate. In general, be vessels very quickly without the G), begin moving up the wall,
sure to complete each part of the imposed mechanical precision of pinching in a very gradual spiral,
process at the appropriate stage of the potter’s wheel. thinning the wall as you go. The
dryness. Do not attempt to bring a As you work through these outside surface may develop shallow
piece that is too dry back to a work- instructions, refer to the accom- surface cracks, but these are not a
able moisture content. panying series of images in Fig. problem as long as the clay doesn’t
Finish the Bottom: This is one 2.2.To begin, wedge a softball-size get too dry while you are still work-
of the most frequently neglected lump of clay thoroughly. Divide ing it. You can smooth these cracks
areas in ceramics. Whether a non- the clay into 2-diameter balls, and with your fingernail or a rib, but, if
functional sculptural form or a loosely wrap all but one in plas- left, these shallow cracks can form
functional vessel, a sloppily fin- tic to protect from drying. Place a very attractive surface texture not
ished bottom or lower edge can a ball in your cupped hand and unlike aged leather. Deep cracks
ruin the appearance and feel of with the thumb of that hand, begin are another story, especially if they
otherwise good work. In general, penetrating the center of the ball. are forming in the rim. As you are
a sharp edge is a mistake, as the With a rhythmic series of motions, expanding the pot and working
form seems to blend into or grow alternate between pressing your your way up the walls, if the sur-
out of the surface on which it sits. thumb into the clay and rotating f
ace begins to crack badly or if the
Unless this is your intention, cre- the ball around your thumb with rim begins to crack at all, you must
ate a slight undercut at the base the fingers of the other hand, keep- tend to it right away. Have a small
to create that all-important line of ing the ball resting in your cupped container of slurry handy, and at
shadow that sets the piece off from hand the whole time. Keep this up the first indication of a bad surface
the surface beneath. until you can feel the pressure of crack or a rim crack, put a very small
your thumb through the bottom amount of slurry on the crack and
Making Pinch Forms of the ball, but stop before it actu- work it back together with your fin-
No matter what one’s intended ally breaks through the surface. You ger or a modeling tool. Otherwise
goals or present skill level in ceram- have now established what will be do not use any water on the surface
ics, the pinch construction method is the center of the bottom of the pot. of the pot while it is underway, as
an excellent exercise and an exciting At this point, instead of pressing water will soften the clay and inter-
way to make small vessels. Whether straight down into the lump, begin fere with your progress.
you are handbuilding or working on pressing the tip of your thumb to As you work your way up the
the wheel, the actions of the hand in the side to widen the bottom of the walls of the pot, the rim may inevi-
squeezing and manipulating the clay pot, again alternating with rotating tably expand more than you want.
and the relationship between the the pot (press, rotate, press, rotate, If this happens, cup your hand
inside and outside of the vessel are press, rotate, etc.). With your thumb over the rim and gently squeeze,
of critical importance. Pinch con- bent, pressing only with the tip of rotate, squeeze, rotate until you have
struction teaches sensitivity to wall the thumb, you will be spreading reduced the rim to the desired



Figure 2.2
Pinch Construction

a. egin pinch construction with a 2
B b. radling and rotating the lump
C
diameter ball of clay. in one hand, penetrate it with
your thumb.

c. otate continuously as you
R d. top when your thumb pressure
S e. inch to the side to begin
P
penetrate the lump. forms a dimple on the bottom. forming the walls.

f. otate continuously, working up the walls.
R g. inch to the final thickness and
P h. ith a finger inside, smear the clay
W
resolve the surface. inwards to reduce the opening.

www.ceramicartshandbook.com | Copyright © 2001, 2007 The American Ceramic Society | 10


diameter. Another good method for been the method known as coil and the personality of the maker
reducing the rim diameter is to construction. This is still the stan- throughout its form. Altogether too
reverse the position of your fingers, dard method in all tribal pottery often, these qualities are erased on
with a finger on the inside under traditions, such as those currently wheel-thrown forms.
the rim and your thumb on the active in Africa and the Americas. In general, a smooth-turning
outside smearing the clay inwards We must avoid any assumption that banding wheel offers tremendous
towards the center of the opening. coil construction is in any way advantages in most coil construc-
Rotate the pot continuously as you inferior or primitive. The form and tion. If a kick wheel is available, it is
do this, and with practice you can surface of a coil pot is controlled by great to be able to rotate the form
close the rim to a very small open- the potter from start to finish with- with your feet while both hands are
ing, or even close it completely to out the influence of any mechani- busy adding coils and smearing them
create an enclosed form. cal devices, and the expressive and together or in modifying the form.
Finish the rim however you wish. imaginative possibilities are endless. Coil vessels are constructed by an
Some pinch-potters like to leave a Even the most uniform and sym- additive process of building up the
thicker rim, whereas others like to metrical coiled pot expresses the walls with long ropelike coils of clay
pinch the rim to a sharp edge. Some beautiful imperfection of humanity (or other repeating modules, such
pinchers like to keep a symmetrical,
even pot and/or rim; others pre-
fer an asymmetrical pot and/or an
uneven rim. Each to his or her own.
Figure 2.3 Rolling Coils for Construction
If you want to have an even, circular
opening, let the pot get leather-
hard, and then trim the rim. If you
are going to sand the pot when dry,
wait until then to resolve the shape
of the opening.
When the pot is completed, you
of course have numerous options
such as the application of tripod
feet, a pedestal base, small hanging
lugs, handles, or other appendages. If
you wish to make spherical shapes,
it is possible with a single lump, but
you also may wish to pinch two
hemispheres and join them when
leather-hard. Pinch construction is
only practical for vessels up to four
or five inches in diameter, so the
addition of ornamental or func-
tional elements can greatly increase
the visual impact.

Coil Construction
Throughout history the prevalent
handbuilding approach has always


as small pancakes). Always start off the coil, bringing both hands back and press a single course of coils in
with a good supply of well-wedged to the center, moving then outwards place, working it well to force out
clay—keep your clay supply cov- again, and repeating the process until excess slurry. As long as you are
ered with plastic so it doesn’t dry you achieve the desired length and using coils of soft clay, you need not
out while you are working. This is diameter of coil. Do not attempt to score and slurry further as long as
critical, as the coils should be very roll coils with stiff clay. Use soft clay, you proceed with adding coils. If
tacky when joined. You must make and make sure the rolling surface you leave the form for a period of
the choice of hand-rolled coils or, if is well dampened. If the coil starts time and the walls begin to stiffen at
the equipment is available, extruded to go oval, purposefully restore it all, then you should score and slurry
coils. You can roll long, uniform to round before continuing with before adding the next coil.
coils very quickly by hand, without your rolling. With a little practice, When adding each successive coil,
the mechanical precision and shape you will be able to roll uniform drape the coil from one hand so that
imposed by the extruder (Fig.2.3). coils of whatever size you wish as the coil end lays on the vessel wall on
If you wish to make a flat-bot- quickly as they can be produced with the far side of the form. With your
tomed form, select an appropriate an extruder. thumb on the inside and fingers on
wooden board or bat and cover it For a small coil pot (8–12 diam- the outside, aggressively smear the
with several thicknesses of newspa- eter) the coils should be K to 1 in coil downwards on the inside with
per. Make a flat slab of clay for the diameter, depending on how aggres- the thumb and upwards on the out-
base—this need not be precisely sively you thin out the walls as you side with your fingers, as shown in
rolled out—you can simply slap a join the coils. For a larger coil pot, Fig. 2.4e. Rotate the vessel (or move
lump of clay between your hands the coils can be I to 1H or more around it) and slowly lower the coil
or pound it out on a flat surface to in diameter. There are several con- onto the wall, smearing it in place as
form a slab of an appropriate thick- siderations here. Once you become you go. Some coilers prefer to apply
ness for the intended form. Usually accustomed to coil construction, you single-level courses of coils one-by-
it’s best to start with a slab larger will be able to anticipate how much one, whereas others tend to coil in a
than the desired base and trim it you thin the coils during the join- continuous slow spiral. It will greatly
back after the lower portion of the ing process. Some tribal potters use help in this process if your coil pot
pot is complete. This also ensures coils that are several inches thick, but is sitting on a banding wheel or
that you always begin coiling the during the joining process the wall a kick-wheel. Tribal potters often
walls on top of the base, rather than is thinned to less than K. Also, once build their coil pots on the ground
by laying the first coils next to it. the basic form is roughed out, you or on a low pedestal and walk
This will give a much stronger joint can come back and thin and form around the pot backwards as they
between the slab base and the coiled it with the paddle-and-anvil or rib- add the coils and work the form. If
walls (Fig. 2.5). and-hand methods described below. you want the form to expand in size
A very thick cylindrical coil form as the walls rise, you can reverse the
Coiling the Walls may be thinned and shaped to a broad smearing movements, smearing up
Roll out (or extrude) a supply of volumetric jar. It is essential that you on the inside and down on the out-
coils. For the best coils, roll them anticipate these things in determining side on the side closest to you. With
on a well-moistened porous or the size of coils to be used. practice you can cause the diameter
canvas-covered table. When rolling Don’t roll out too many coils to increase or decrease at will by
coils, spread your fingers apart (see ahead of time, because if they stiffen altering these movements. Do not
Fig. 2.4) and, as you roll forwards up at all they will not join satisfac- worry about cosmetic surface dur-
and backwards, quickly move your torily. Score and slurry the desired ing this process. If you are smearing
hands outwards towards the ends of attachment point on your base slab, aggressively, you will leave a rather



Figure 2.4
Coil Construction

a. esuming coil construction on an in-prog-
R b. Apply a coil and gently paddle in place.

ress vessel: Score and slurry the edge.

c. mear the soft coil downwards inside
S d. s the next coil is lowered into place,
A e. dd additional coils.
A
and out over the stiffened edge. smear it aggressively onto the previ-
ous one.

f. fter every three or four courses,
A g. mear additional coils inwards to
S h. o further close the rim
T
smear the coils together with diago- reduce the opening. opening, smear inwards
nal strokes. with a rib.



ragged surface appearance, but this Meso-American, and Southwest convolutions and formed or assem-
is evidence of well-joined coils. It is Native American cultures all feature bled immediately. With the stiff-slab
a simple matter to stop periodically extraordinary design and technique method, the slabs are allowed to dry
and smear the surface smooth with in coil construction. to leather-hard and are then cut to
your fingers or a rib. size and joined together.
Be careful when increasing or Closing the Mouth
decreasing the diameter of your coil of a Coil Form Rolled Slabs and
form to any radical degree, because When you wish to narrow the “Memory”
the clay must have the structural neck or mouth of a coil vessel you When clay is formed by applica-
integrity to support itself. Any time can simply apply the coils to the tion of pressure, the clay mass is
a clay wall veers away from the verti- inner surface of the rim and smear compressed and the platelets are
cal, gravity will make it tend to lean inwards on the outside of the vessel. pushed around in currents, depend-
or collapse. If you are contemplat- As a refinement of this, support the ing on the type and direction of
ing a radical expansion or reduction inside of the rim with your fingers pressure applied. The clay retains a
in diameter, you must either allow and smear inwards over the top sur- memory of the compression and the
the clay to harden sufficiently as face of the rim with a rib, rotating currents, and it will shrink accord-
you proceed, or you must provide a the form continuously. As long as ingly during the drying and firing.
physical support for the clay. there is sufficient thickness in the This is true with all forming meth-
If you leave your vessel for any rim, you can close the opening as ods, but it is rarely a problem. In slab
time, always cover the top coil with much as you want by this method. If construction, however, it must be
damp paper towels to keep it moist the rim is not thick enough to allow taken seriously. When rolling slabs
and wrap the whole pot in plastic. this, stop and add another coil, and with a slabroller or rolling pin, if you
When you resume work, if the then proceed with this method. roll only in one direction, you are
top coil has stiffened at all, always setting up a grain structure similar to
score and slurry before proceeding, Slab Construction a wooden board. Both a board and
and paddle the first coil in place to Of the primary ceramic form- a unidirectionally rolled slab have
ensure a good joint (see Fig. 2.4b). ing techniques, slab construction is greater strength along the length
If there seems to be a lot of con- the most modern. The technique than across the width, but will shrink
densation inside the plastic in your of constructing with clay slabs is more across the width than along
studio environment, drape a cloth or suitable for a wide variety of forms the length. If you assemble a large
sheets of newspaper over the form and is the ideal method for achiev- slab form from these slabs, with the
before covering it with plastic. This ing flat-sided geometric and archi- grain structures intersecting at angles,
diffuses any moisture, which evapo- tectural forms. Historically, such the piece will likely pull itself apart
rates and recondenses where the forms were generally built by the because of differential shrinkage in
plastic touches the form. Without coil method, and except for the the drying and/or firing, especially
this precaution, the condensation remarkable slab-constructions of with high-shrinkage claybodies, and
can concentrate and cause the clay pre-Columbian Meso-America, in high-fired work. This is the most
form to collapse. there is little evidence worldwide common problem area in slab con-
The possibilities of coil construc- of slab construction before the struction. There are several solu-
tion are unlimited, so almost any twentieth century. tions. If your slabroller has a wide
object or form can serve as inspira- There are two primary kinds of enough bed, initially roll the slab
tion. The ancient and tribal tradi- slab construction.With soft-slab con- thicker than you want, turn the slab
tions of East Asian, Middle Eastern, struction, the slabs are manipulated 90 degrees, reset for a thinner roller
Mediterranean, African, Peruvian, while still soft to form curves and height, and roll the slab again. With



hand-rolled slabs, simply change the laying across the table pointing away degrees, and reroll until you get the
rolling direction frequently. In either from you, with the clay between the size, shape, and thickness you want.
case, this will equalize the compres- two slats, and with the ends of the For greatest accuracy, measure the
sion and currents, minimizing subse- rolling pin resting on the two slats, thickness in several places with a
quent problems. you can roll slabs to an exact thick- needle tool, just as you would mea-
All slabs are subject to this ness. However, with practice you sure the bottom of a pot.
p
roblem, whether you are mak- can roll slabs very uniformly with-
ing slumped dinnerware, geometric out using the slats, and you are then Soft-Slab Construction
boxes, or tiles. In all cases, memory able to make use of the full width Soft-slab construction is the pre-
of improper rolling can ruin the of the rolling pin. In either case, be ferred method for a wide variety of
finished product. sure to turn the slab 90 degrees sev- vessel and sculptural approaches. It is
eral times while rolling to equalize ideal for any form that may be cre-
Rolling Out Slabs the compression. ated by wrapping or draping slabs on
Commercial slabrollers are a Pound your clay into a rough slab, slump or drape molds, or by simply
wonderful innovation, and if your place it on an appropriate sheet of manipulating a soft slab by hand. The
work calls for quantities of large canvas (depending on the size you following is a range of very simple
uniform slabs, you should consider want) on a sturdy table, and start projects that will serve as a good
this major investment. If you do not rolling it, changing directions fre- introduction to soft-slab construc-
have a commercial slabroller at your quently.Very soon the clay will stick tion and should provide a foundation
disposal you can easily roll out your to the canvas and won’t expand any for more ambitious soft-slab work.
slabs by hand with a rolling pin. As more. Lay another sheet of canvas
long as you don’t need really huge on top, grab both sheets and the Soft-Slab Cylinders
slabs, this is not a disadvantage, as slab, using the broad surface of your A wide variety of cylindrical or
with practice you will be able to fingers to minimize distortion of cone-shaped vessels may be made
roll out slabs by hand almost as the slab, and flip the whole work free-form out of soft slabs. Cups or
fast and just as uniform as with a over. Pull off the top (formerly bot- mugs provide an excellent soft-slab
slabroller. Even if you are using a tom) sheet, pull the wrinkles out of project, and for these you should use
slabroller, keep in mind also that the the bottom sheet, turn the slab 90 slabs no more than G thick. Cut a
roller tends to stretch slabs only in degrees, and roll some more. Roll strip of slab as wide as the desired
the direction of travel. In order to out from the center, and minimize height of the cup and as long as the
avoid irregular shrinkage or serious pressure as you approach the outer desired circumference. Score and
warping, these slabs should really edges, because it is very easy to get slurry the ends of the strip and join
be aggressively hand-rolled on both the slab very thin at this point. Roll them together to form a cylinder.
sides at 90 degrees to the original along the edges as well, but when You can either butt-join them (end
direction of travel. doing so, apply much more pressure to end) or you can overlap the ends.
against the end of the roller that is Set the cylinder on a flat piece of
Rolling Slabs by Hand on the slab than that hanging over slab and, with your needle tool,
Using an extra-long rolling pin the edge. With practice, you will mark lightly around the bottom
with bearing-mounted handles, you find that by rolling outwards from circumference. Remove the cylin-
can quickly roll out very large uni- the center and along the edges in der and score and slurry inside this
form slabs. If you need absolutely specific directions, you will be able circle, then press the cylinder gently
uniform thickness, make a series of to control the way the slab expands into place. Cut away the excess base
pairs of long wooden slats in gradu- and thus control the finished shape. slab, turn the cup over, and gently
ated thicknesses. With a set of slats Continue to flip the slab, turn it 90 tap the bottom slab around the



edges to join it more firmly to the This is an excellent technique to molds made from plywood or foam
cylinder. Finish the cup however use if consistency and uniformity of insulating board have become very
you wish. An alternate approach is size and shape are desired, because popular. When these are set on a
to use bisque stamps or a sheet of all the vessels made from one mold flat table surface, clay slabs may be
textured material to create a pattern can be very similar in size and shape. slumped into these forms to create
or texture in the flat slab before Professional potters make their flat-bottom plates and trays. Similarly,
making it into a cup. molds out of plaster, bisque-fired simple hump forms of plaster, wood,
If you want uniform, evenly clay, plywood, or foam insulating or foam board provide excellent
matching cups, you may wish to board, but almost anything of the hump molds, and when slabs are
form your cups around a removable desired shape will work as a mold. slumped facedown over such molds,
core such as an empty soda can. Cut See Figs. 2.5 and 2.6. the edge may be trimmed and a foot
a strip of G-thick slab and wrap it You can make bowls and plates ring added immediately, minimizing
around the soda can to determine by simply slumping slabs inside an later finishing.
the length of strip needed, then lay existing bowl or plate. Whenever For improvised slump-molds, shal-
the strip back down on the table and the “mold” is a nonporous material, low forms work best, where a single
cut it to length. Wrap an appropriate be sure to use several layers of news- slab can usually be gently pressed
width and length of dry newspaper paper strips beneath the slumped or into place. If you use a deep bowl
around the can (or other cylindrical draped clay to keep it from stick- as a mold you will have to apply the
form). Don’t try to do this without ing to the mold. With slump molds slab in several pieces, scoring, slur-
the layer of dry newspaper, as you made of plaster, bisque-fired clay, rying, and vigorously connecting
will be unable to slide the form out plywood, or foam board, no news- the joints. After the bowl stiffens up
of the cylinder. Score and slurry paper layer is required. Open-center a bit, invert it on a board, remove
the ends of the slab-strip, wrap it
around the newspaper-covered can,
and join the ends together. While
the clay strip is still wrapped around
the can, if you wish you may press Figure 2.5 Foam Slump Molds
bisque stamps or textured materi-
als into the surface for decoration.
After you have joined the ends of
the slab strip and added any addi-
tional stamped decoration, hold the
cylinder carefully cradled in one
hand, push out the can, and remove
the newspaper. Proceed with adding
the bottom as explained above.

Slump-Molds
In the current world of functional
and decorative ceramics, slump- or
drape-molded bowls and platters
a. sing a foam slump mold: Drape
U b. ently drop the mold repeatedly
G
have become extremely popular. to settle the slab into the mold.
a slab over the mold.
This method simply involves slump-
ing a soft slab inside or over a mold.



the mold or form, and use a wooden the added advantage of allowing you to the subject. There are a number of
rib or modeling tool to smear together to add a raised foot-ring to the base if ways to make tiles. The simplest is to
any wrinkles or gaps on the outside you wish. However, if you try to slump roll out uniform slabs with a slabroller
surface. Or, as a decorative option, a deep-dished form on the outside sur- or by using a large rolling pin with
make sure to smear the inside connec- face of a rigid mold, you must remove a set of wooden slats as previously
tions very well and leave the outside it while still very damp, as any drying described. Let the slab stiffen to soft
seams visible. shrinkage could cause it to crack. leather-hard, and then carefully cut
As mentioned, you can slump inside your tiles using a razor knife and a
or outside of a mold or form. If you Making Tiles straightedge, taking into consider-
slump a very shallow platter or bowl There are some excellent books on ation drying and firing shrinkage.
over a convex form, you may be able the market about tile making, and this Be sure to consult the section on
to allow it to dry in place, and this has will be only a very short introduction “Rolled Slabs and Memory.” If you

Figure 2.10
Foam Hump Molds

a. sing a foam hump mold: Place
U b. ently drop the board repeatedly
G
the mold on a board and drape to settle the slab over the mold.
the slab over it.

c. core and slurry the back to accept
S d. lace a coiled foot ring and gently
P e. lean off excess slurry with a
C
a foot ring. paddle it level. damp sponge.



make tiles from improperly made slabs, then this method will not work. In
the clay memory will cause them to this case, the best solution is to simply
warp during drying and/or firing. make sure that the tiles are mobile
Some production tile makers extrude (they are not stuck to the surface) and
their tiles from a pugmill, using a spe- ensure that they dry slowly and evenly
cial extrusion die with a thin horizontal under plastic or in a controlled humid-
opening, producing a long continuous ity environment like a damp/dry box.
ribbon of clay that can be cut to any Whatever method you use for mak-
desired length. For small quantities of ing tiles, if your intention is to glaze
tiles, a similar extrusion die on a stan- them, all your efforts will be wasted
dard clay extruder works quite well. unless you use a glaze that is a perfect
Drying tiles is always a challenge, in match to the claybody. This is espe-
order to produce perfectly flat tiles. cially true in high-fired tiles, where the
One good approach is to sandwich the clay becomes very pyroplastic. If the
tiles between 24 squares of 1⁄ 2 dry- firing shrinkage of the glaze is greater
wall (sheetrock) until completely dry. than the clay, the tile will become
For economical use of space, you can concave during the glaze firing. If the
stack up to six layers of drywall and firing shrinkage of the glaze is less than
tiles. Obviously, this method works the clay, the tile will become convex.
only for tiles that are of absolutely You can do simple tests ahead of time
uniform thickness, are completely to determine which glazes are appro-
flat, or have only shallow incised or priate for your tiles. When necessary,
impressed decoration. you can adjust the formula of a glaze
If the upper surface of the tile is not to correct thermal expansion and make
flat, or if the thicknesses are irregular, it fit your claybody. •


Throwing
Chapter 3

Of the various ceramic construction methods, throwing on the
potter’s wheel is the most common in Western, European-based culture.
For producing large quantities of individually handmade functional wares
it is the most efficient method. A traditional approach to throwing involves
completion of the pot upon the wheel so that very little needs to be done
afterwards to finish the form.This is especially true of certain jar, vase, bottle,
and bowl forms. Even if a trimmed foot or a knob is needed, we often use
the wheel for those tasks as well. It is a joy to use the wheel in this way, but
consider also that the wheel is an extremely versatile tool for making com-
ponent parts to be assembled off-wheel into vessels or sculpture. The wheel
excels for making hemispheres, spheres, ovoids, flat disks, cylinders, cones,
tubes, and myriad other shapes. All of these components can be assembled
in an unlimited number of ways. If you do not explore these possibilities,
you are missing one of the best things that the wheel can do.

Critical Points in Throwing
The following review is designed to help beginning clayworkers become
familiar with the most important points in throwing. There are lots of steps
to keep track of, and it will help greatly to go over this list frequently and
commit it to memory.
Prepare Clay Properly. Wedge the clay thoroughly before using. This
is especially important for wheel-thrown work. Don’t waste time on clay
that is too wet or too dry. If clay is too wet, let it sit out until stiffened
adequately and rewedge, or wedge it on a dry plaster surface, or wedge in
some dry material (although this decreases plasticity). Don’t try to reuse
clay from a previous pot that didn’t work out—let it stiffen up and rewedge
it before using again.
Prepare Plenty of Clay. With only one or two balls of clay in reserve, it
is easy to develop an attitude of preciousness about each pot and a despera-
tion to make each one work. Always prepare at least a dozen balls, and if a
pot is not working, remove it immediately and start another one.


Throwing • Chapter 3

Clean and Dampen the for any shaping task. If you want and finishing small vessels. Use slow
Wheelhead. The ideal surface for to smooth or flatten a broad area, speed for large vessels.
receiving the clay is slightly damp use a rib. Action→Reaction. For every
but not wet. Use a rubber rib to Centering: Full Body Con action there is a reaction. Keep in
squeegee off all remaining slurry trol. Centering and wheel wedg- mind the consequences of every
from the previous pot, and if any ing depend on full body control. type of pressure that you apply to
surface moisture remains, remove it The work is not done by your arm the clay, and, when lifting or shap-
with an old towel (Fig. 3.1). muscles, but rather by the full force ing a vessel, apply corresponding
Slap Center. Before applying of your upper torso when you roll pressure both inside and outside the
water, slap center a ball of prop- your hips forward on the chair or form. Avoid expanding the diameter
erly prepared clay on the wheel- bench (Fig. 3.3). of a form without pressure from
head or bat, and seal down the Work on the Right-Hand both sides, unless you are very sure
edges thoroughly (Fig. 3.2). Side of the Wheel. After center- of the anticipated outcome.
Avoid Touching the Clay ing, always work at the right-hand Lubrication. While throwing,
When the Wheel Isn’t Turning. side of the wheel where the clay keep the clay lubricated adequately
Except for slap centering, always is moving away from your hands at all times. Excess friction is your
start the wheel before applying (assuming you are throwing counter enemy. But remember that water is
pressure, and always remove pressure clockwise). continuously absorbed into the clay,
before stopping the wheel. Work at the Correct Speed. decreasing structural stability. As you
Aggressive Commanding Use full speed for centering, wheel practice throwing, try to work fast.
Approach. Clay appreciates a wedging, and penetrating the lump Remove Excess Water. Remove
vigorous commanding approach of clay. Use medium speed for wid- excess water whenever possible and
with an economy of motion. Be ening the bottom, lifting the walls, as soon as possible. If you work
clear about the specific reason for
whatever you do, and remember
that with an aggressive, adventur-
ous approach you will learn very Figure 3.1 Throwing Position
quickly. Take risks.
Concentration of Pressure
Points. All stages of manipulating
the clay depend on concentration
of pressure points. Concentrating
force on a small area of the clay
will give much greater control
than broad application of pres-
sure over a large area. Centering
primarily involves pressure with
the base of the right hand. Lifting
the walls involves pressure with
slightly bent fingertips rather than
the flats of the fingers or the hand.
Once the clay has taken the form
of a basic vessel, you should never
Proper seating position when throwing.
use the broad surface of your hand



slowly and a piece begins to soften, inwards before cutting the pot off in throwing is to keep the outside
you may remove excess water and the wheel. When cutting off pots, profile and inside profile as similar as
slurry with sponges and ribs. When hold the cutoff wire very taut. possible. In other words, if the walls
you reach an approximation of the When cutting off large flat shapes, are of uniform thickness, then the
desired shape you may remove all always do so with the wheel turn- outside and inside will be very close
excess water and do the final shaping to keep the cutoff wire from to the same contour, whereas if the
ing with fingers, damp sponges, climbing up into the base of the pot. lower wall is very thick, the outside
throwing stick (jug finger), or rub- Trim or otherwise finish the bottom and inside will be very different in
ber, metal, or wooden ribs. carefully, and make sure that there shape. Start off with a series of six
When Throwing, Use the is a line of shadow around the base, or eight small cylinders, working
Best Tool for the Job. Usually separating it from the surface upon up to about 4 or 5 in height. Try
we throw with our fingers, but which it sits. to achieve walls that are no more
that is not always the best choice. than K thick at the bottom and G
When throwing porcelain, it often Skill Development just below the rim, with a smoothly
works very well to throw with a with Cylinders tapering wall in between. The bot-
sponge on one side and a rubber or One of the best ways to develop tom thickness is not so crucial, but
metal rib on the other, or even with your ability on the wheel is to throw remember that if you wish to trim
two rubber or metal ribs, especially lots of cylinders (Fig. 3.4). As you the bottom it should be K to H or
when making broad, voluminous complete each one, cut it in half more thick (this will give you ample
forms. When making a tall form vertically with your cut-off wire thickness for trimming a raised foot-
with a narrow rim, it makes sense to to observe the cross-section pro- ring), and make sure that the bot-
neck in the rim immediately upon file. Don’t try to do this with other tom is flat and level, with a distinct
achieving the desired height, and shapes, because they will collapse as rounded corner where the bottom
then use a jug-finger to broaden the soon as you cut them, whereas half ends and the wall begins. Later you
body of the vessel. of a cylinder will still stand up. When may wish to throw forms with a
Attention to Rims. When lift you view the cut cylinder there curved bottom, but for skill develop-
ing walls, always stop just short of are several important things to look ment it really helps to become famil-
the rim. Compress rim regularly, and for. First of all, a primary objective iar with flat-bottom cylinders.
on cylinder-based forms keep rim
diameter smaller than base diameter
until wall height is established.
Synchronize Movements. Figure 3.2 Slap Centering
When lifting or wheel wedging,
synchronize the movement of your
hands with the speed of the wheel
so as not to leave deep spiral grooves
or marks. Much of the problems
in learning to throw are caused by
lifting too fast in proportion to the
speed of the wheel.
Cutting off the Pot and Fin
ishing the Bottom. These can
Seal the lump down with the lower edge of your hands while the wheel is
make or break an otherwise good turning slowly.
pot. Always bevel the lower edge



When you cut each cylinder in mentioned earlier, centrifugal force not attempt to repair it. If there is
half remember to carefully observe tends to force the clay outward from sufficient clay below the crack you
the uniformity of the walls, the the center, and in making bowls may cut away the damaged portion
smoothness and thickness of the you can take advantage of this force and proceed with what is left.
bottom, and the uniformity and rather than having to counteract As a general rule, in the early stage
thickness of the rim. There should it. When lifting the walls, simply of throwing any form it is wise to
be very little variation in thickness lift outward and allow the form avoid radical horizontal orientation
of the walls from bottom to top, to expand. Be especially careful to of the clay. In other words, in lift-
and the lower inside corner should compress the rim with every lift, ing and widening a bowl form do
be quite square, as indicated in Fig. because the rapid expansion of the not widen the bottom too much
3.5g. With each successive cylinder, diameter can easily cause the rim to initially so that it hangs over the
try to respond to the problems or crack. If the rim does crack badly do foot. Instead, raise the walls so that
faults in the previous ones, so that
you are continuously experimenting
and developing your technique. Figure 3.6 Throwing a Bowl
If you find yourself frustrated with
the ordinary cylinder, try doing
timed cylinders. Sit down at the
wheel with 20 or 30 small balls of
clay, and have someone time you.
This is a great exercise to do in a
classroom situation. Start with five-
minute cylinders, with 30 seconds
in between to scrape off the previ-
ous one and put a new ball of clay
on the wheel. When time is called,
immediately stop the cylinder you
are working on and scrape it off the
a. hrowing a bowl: Lift outwards.
T b. ift repeatedly, maintaining
L
wheel. After two or three of these,
straight walls.
reduce the time to four minutes,
then three, two, and finally one-min-
ute cylinders. You will be absolutely
amazed at the progress you can make
through several of these sessions.

Throwing Bowls
Generally, most bowls are thrown
on bats. In making bowls, penetrate
the lump and widen the bottom
just as in forming cylindrical forms,
but there is no need to undercut
when widening to keep the opening
c. rim away excess clay from base.
T d. esolve shape with rib, fingers, or
R
narrow. This will result in a wider, sponge.
lower doughnut-stage (Fig. 3.6). As



Figure 3.3 Centering

a. entering and wheel wedging:
C b. rofile of properly centered lump.
P c. ontinue the side pressure while
C
Initially center the clay with firm hinging hands together, causing
side pressure. clay to rise.

d. ross section showing intermedi-
C e. aise the lump to a rounded peak.
R f. ross section showing maximum
C
ate stage of wheel-wedging. rise, with heel of thumb poised to
press clay back down.

g. ith continuing side pressure to
W h. ontinue pressing downwards as
C i. inalize centered form after
F
prevent mushrooming, press clay lump widens. repeated wheel-wedging.
back down.



Figure 3.4 Throwing

a. asic throwing: After centering
B b. enetrate the lump to create a
P c. iden the bottom using the “claw”
W
and wheel-wedging, form a dim- V-shaped opening. motion, and compress the bottom.
ple and apply water.

d. egin lifting the walls.
B e. aintain firm, even pressure and
M f. top lifting just shy of the rim.
S
steady upwards movement.

g. ompress the rim.
C h. egin second lift, pressing into
B i. ontinue lifting slowly and steadily
C
the clay at the base. up to the rim.

j. epeat with the third lift.
R k. egin shaping the vessel as you
B l. hink about the shape as you fol-
T
lift. low through.



Figure 3.5 Throwing Cross Sections

a. ross sections of basic thrown
C b. enetrating the centered lump.
P c. idening the bottom.
W
form: Creating the dimple.

d. he initial lift.
T e. top just shy of the rim.
S f. econd lift, pressing into the base.
S

g. roper position during lifting,
P h. inal lift.
F i. esolving the shape.
R
with inside fingers slightly ahead
of outside fingers.



they are straight or slightly convex shape you desire. For small bowls the open, depending on tempera-
(like the flare of a trumpet) rather it is generally best to finish the ture, humidity, and air movement. If
than concave (like a hemisphere), shape with your fingers, but for you won’t be able to get back to it
and make sure that initially the larger bowls it usually works best until the next day or later, you must
walls flare out at no more than a to use a sponge or a curved rib to cover it with plastic sheeting. The
45º angle from the bottom. This is establish the inside profile. With best material to use for this is a dry-
an extremely stable form that will the wheel rotating at low-medium cleaner bag or trash bag cut open to
allow you to achieve the desired speed (medium for a small bowl, form a rectangular sheet. Wrap the
height, diameter, and wall thickness. low for a large one) work the fin- plastic under the edges of the bat
Before proceeding further, always gers, sponge, or rib up from the or ware board to prevent air cur-
trim away excess clay from the out- bottom of the bowl, curving the rents from drying the pot. In very
side base, (Fig. 3.7) because it will be clay outward a little with each pass dry weather, especially in the winter
very difficult to get access to this area from bottom to top. With your right when a forced-air heater is running,
when the curvature of the bowl is hand, always follow the position of a pot may dry out in a day or two
complete. If you are planning to trim the rib with gentle sponge or finger even when well wrapped. Check
the bowl, then you need only trim pressure on the outside of the bowl. your pots frequently, and if they are
away excess clay and create a slight Repeat these passes until the bowl drying too much, spray them lightly
undercut to facilitate cutoff. If you takes the desired shape. When using with a household spray bottle filled
are not planning to trim the bottom, a rib to shape a bowl be sure to with water. If you anticipate having
you can undercut the edge with a incline it so that it slides smoothly to leave them for several days and
wooden rib, applying gentle pressure over the clay rather than scraping or are concerned about excessive dry-
with a sponge to the outside base, cutting into it. ing, you can drape dampened paper
and create a very pleasing “foot.” towels or rags over your pots or sim-
For small bowls you may use your Drying Your Pots ply place several wads of wet paper
fingers, a sponge, or a curved rib to It is possible to throw some shapes towels on the ware board next to,
bring the walls out to the desired so that they have a perfectly accept- but not touching, the pots and wrap
curvature. On large bowls it is a able base straight off the wheel, with them securely in plastic. Even in
good idea to remove all slurry and very little finish work (Fig. 3.7). In very dry weather, this should keep
water from the inside and outside most cases, however, you will need them at the leather-hard stage for at
surfaces before final shaping. You to trim the bottoms of your pots. least a week.
can accomplish this with a sharp- After finishing the pots and plac- Pay very close attention to the
edged rib, like the standard stain- ing them on ware boards you must drying process. It is much easier
less steel kidney-shaped rib. You anticipate when you will be able to trim a pot or add handles with
can also squeeze all water out of to work on them next and pro- good results when you do it at the
two sponges and, with the wheel tect them appropriately from exces- proper soft-to-medium leather-hard
at slow-medium speed, use them to sive drying. All trimming, attaching stage. Checking pots frequently to
remove water and slurry from the of handles, slip painting, applique
surface. Either of these techniques work, and most decorative carving
will in effect “wring” water out of must be completed at the leather-
the clay, firming it up structurally so hard stage, when the clay is stiff
it is less likely to distort or collapse enough to handle but still damp.
as you proceed. Upon completing a pot, if you
Final shaping can be done with a plan to trim it later that same day
variety of tools, depending on the you may be able to leave it out in



monitor drying is simply part of the forth, until the four lumps are equally surface and to the trimming tool. If
process. If a pot dries beyond proper spaced around the pot. Maintain pres- the clay is too dry, it will feel very
trimming stage before you trim it, sure with your hand against the center hard and scratchy when trimming.
don’t waste time on it—recycle it. of the pot throughout this process, Do not continue with trimming if
so that it doesn’t shift on the wheel- the clay is too wet or too dry.
Finishing the Bottoms head. For a low bowl, plate, or cup After the bottom is completely
shape, very small lumps are adequate. level, begin trimming off all excess
of Your Pots For taller mug and jar shapes, larger clay from the outer edges of the
Place the pot upside down in the lumps will be necessary. The lumps base. If the lower walls are thick
center of the clean wheelhead. Start should never be pressed hard against you may trim some clay off them,
the wheel at slow speed, and hold
the clay form, but they always must but try not to rely on this any more
one finger near the edge of the pot.
be smeared down thoroughly against than necessary. As much as possible,
Slowly move it in towards the pot
the wheelhead. trim the excess clay off the lower
until your finger touches the edge
When selecting trimming tools, walls while the pot is still wet on
of the pot once on each rotation.
you will have the greatest control the wheel.
This is the point where the pot
with a very small trimming sur- When trimming a leather-hard pot,
is farthest off center. On the next
face. The corners of a square-ended remember that the objective is to
rotation when the pot touches your
band-loop trimming tool give you make the outside profile (except for
finger, stop the wheel right at that
the best option. Hold the handle of the foot ring) as much as possible like
point. Move the pot slightly towards
the tool in your right or left hand the inside profile, and trimming excess
the center of the wheel and repeat
just as you would a pen or pencil, wall thickness is perfectly acceptable.
the process until the pot seems on
with the square end pointing down. Use the flat cutting edge to refine
center. When you get good at this,
Brace it firmly near the tip with the trimmed area and to blend it into
you may wish to try the tap-center
the fingers of your other hand and the untrimmed part of the wall. Use
method, where you gauge whether
with the cutting edge of one corner the curved end of a trimming tool to
the pot is on center as described
above, but then, without stopping begin trimming the pot—remember trim any convex areas.
the wheel, tap the form to move concentration of pressure points. If the bottom of the pot was quite
it further on center. Many profes- Bring the wheel up to medium thin to begin with, you may not
sional potters use this method and speed, start at the center, and trim a be able to trim a raised foot ring,
can center a pot almost instantly. If slow overlapping spiral all the way in which case the trimming pro-
you are not accustomed to it, it may to the outer edge. If the bottom is at cess is finished at this point. If you
seem all but impossible. all irregular in height, then you will really want to find out how good
When the pot is centered, form need to take repeated passes to trim a job you’re doing, you may have
four small lumps of clay, each the size it down to level. Hold the tool very to sacrifice a few trimmed pots by
of your thumb. While gently applying firmly close to the tip with both cutting or breaking them in half to
downwards pressure against the center hands during this process to over- observe the cross-section profile of
of the bottom with one hand, press come any irregularity in the bottom. the trimmed bottom.
one lump in place, gently nestling If the clay is the proper medium If there is enough thickness to
the lump against the pot and apply- leather-hard, then it will trim very trim a raised foot ring, after you have
ing primary force to smear the lump easily and evenly, and the trimmings leveled the bottom and trimmed off
down against the wheelhead. Avoid can be easily brushed off the surface any excess clay from outer edges
applying excessive pressure against the with a soft brush or with your fin- and lower walls, examine the profile
pot. Rotate the wheel and pot 90º, gers. If the clay is too wet, the trim- of the pot and decide what kind of
press another lump in place, and so mings will ball up and stick to the foot ring you want. In some cases


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