make pottery

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make pottery
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©2009 Ceramic Publication Company
how to learn pottery techniques
and enjoy working with clay
This special report is brought to you
with the support of Ringling College of Art + Design.
How to Make Pottery
How to Learn Pottery and Enjoy Working with Clay
When you put your hands into clay, there’s a good chance you’ll never want to stop. Just go by any ceramics class or
community craft center and look at the people working with clay and you’ll see one happy group of involved people of all
ages enjoying the thrill of creating with their hands. Unlike a phone app, music download or video game, once you possess a pottery technique, it’s yours for life.
Clay Slab Project: Plates
By Amanda Wilton-Green
A good first project to get the feel of clay is to make slab plates. This project uses
simple tools but has endless possibilities. Using Chinet plates for molds, you can
learn how to work with clay, make slabs and decorate pottery.
Pinch, Slab, and Coil Pot Project:
Spherical Teapots By Ron Korczynski
Ron was a pottery teacher for 32 years before retiring in 1995. Since then he’s
been perfecting the same techniques he taught students for many years—it’s just
a matter of practice. This teapot begins with two pinch pots put together then
parts made from coils and slabs added to it. The possibilities are endless.
Throwing: A 3-Stage Approach
Throwing on the W
by Jake Allee
Tips for success
 Always apply and release pressure to
the clay slowly.
 Never allow water to collect in the bottom of the piece.
 Slow the wheel down in each step of
the process.
 Be persistent in your efforts.
By Jake Allee
Teaching throwing is challenging even to the best of pottery instructors. Jake
Allee approaches the topic with his students on several levels that include
reading, visual diagrams, demonstrations and hands-on technique. Whether you
want to teach throwing or you’re wanting to learn on your own, Jake has some
advice for you.
How to Glaze
large
throw
cenTer
 Start
that’s
hands
diagram illustrating hand to clay pressure.
By Annie Chrietzberg
For a lot of people, glazing can be the party pooper for an otherwise extremely
fun time. It doesn’t have to be. When glazing is done right, the piece you’ve
spent so much time on can really be outstanding. Annie Chrietzberg offers 14
steps for successful glazing.
Ancho
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Wet y
Slowly
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clay profile
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When
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Once
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©2009 Ceramic Publication Comp
10 Hot Kiln Tips
by David L. Gamble
David conducts a lot of workshops for K-12 teachers and he answers many
questions about problems related to firing pots. Here are 10 really great tips that
will solve the majority of problems anyone can have with a kiln and you’ll see that
the maintenance tasks will keep your kiln running smoothly for years.
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Clay Slab Project: Plates
by Amanda Wilton-Green
Making slab plates is a great way to develop basic slab techniques, and using Chinet® plates for forms makes this an
affordable class project. They also make perfect surfaces for exploring decorating techniques.
M
aking a set of ceramic plates can be fun for the
beginning student, but is also easily adapted
for the more-experienced student. This project presents a direct and fresh slab-forming approach resulting in plates that become great canvases for surface
decoration. Materials are simple, inexpensive and
readily available.
After only a few hours of work, students learn
how to roll out a good, even slab, and can experience
different stages of plastic clay and what the clay is
capable of at each stage. They become familiar with
simple slump molds and start to consider the form and
function of their work. Most importantly, they learn
how to handle clay in a direct and intentional way.
These plates become a wonderful surface for lessons on finishing, embellishing and glazing. I have
expanded this lesson to include experiments with
paper stencils and slip decoration, but that’s just the
beginning. Try underglaze design work and glazing
methods with this lesson as well. When the project is
completed, students have a set of plates to use in their
homes or give as gifts.
Forming Plates
Equipment and Tools
• Large rolling pin
• Cut-off wire
• Sponge
• 25 lbs of clay with sand or grog
to reduce warping
• Fettling knife or needle tool
• Chinet® paper plates.
Note: Chinet® plates do not have a plastic coating
and absorb moisture from the clay. Avoid coated
and plastic plates that will stick to the clay.
1 Roll out a slab to a desired thickness of ¼ to
½ inch. When rolling out a slab, start by throwing it
across the table in different directions until it is somewhere close to 3 inches thick. Roll the clay with the
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2
rolling pin, taking care not to roll over the edges. Roll
two or three times on one side. If you are working on
canvas, you’ll notice that the clay stops stretching after
the first few times because the clay holds onto the texture
of the canvas. Carefully lift the slab creating as much
surface area with your hand as possible, and leave the
slab to stiffen to a soft leather-hard stage. The clay needs
to be able to bend without cracking, but you don’t want
fingerprints to show as you manipulate your clay.
1
2 Choose the size of your plate. Chinet® brand has
dinner, salad and dessert-sized plates as well as an oval
platter. Place the plate upside down to use as a template
for cutting the slab (figure 1). As you cut, keep your
needle tool or fettling knife perpendicular to your work
surface to create a square rim.
3 Remove excess clay and smooth out the rims.
Slide your finger across the edge of the rim with firm and
consistent pressure (figure 2). The sharp corner of the
rim softens without flattening the edge. A damp sponge,
chamois or a small piece of a produce bag also works.
Stamp or sign the underside.
2
4 Flip the clay slab, smooth the top edge then place
it into the paper plate, lining up the edges (figure 3).
Experiment with pressing the clay into the paper plate
with your hands or sandwiching your clay between two
plates (figure 4). The clay will have a different character
depending on your chosen method.
5 Allow the plates to dry to a firm leather-hard stage
in the bottom paper plate. Remove the clay from the
mold to check to see if the plates stack nicely and sit on
a flat surface without rocking. Take a moment to look
closely at the rim of each plate to do any final shaping
they might need.
Decorating Plates
3
These plates are adaptable to all sorts of decorative techniques at the leather-hard, greenware and bisque stages.
The flat surface lends itself to painterly and expressive
underglaze or glaze work. These slab plates are simple
enough for very young students and satisfying for the
adult student.
Slip decoration gives dimension to the plates and
students draw on their own creative design ideas for the
work. Textured dessert plates with slip inlay use found
and inexpensive materials (see box) to create a design
and a slip in contrasting color to further highlight the
design. Paper stencils used with decorative slip can make
bold, graphic borders or motifs for your set of plates
(figure 5). With a little experimentation and practice,
students come up with wonderful results.
Making Sets
4
When we handbuild a set of plates, the student and
experienced artist approaches each plate with a slightly
different perspective. The experience of making the first
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plate, bowl, mug or tile influences the next, as do things
as simple as body position and energy levels. We’re
thoughtful and inconsistent creatures and we can use
these characteristics to great benefit when done so with
intention. A set of plates can be tied together with a
theme, color, position of image, size or concept. Because
we’re used to seeing sets coming from a factory, the
default definition in our minds can be limited to identical
objects. This lesson is a great way to discuss the many
possibilities for sets in functional ceramics and can demonstrate the benefits of using handbuilding techniques.
Textured Dessert Plates
Roll out ¼- to ½-inch-thick slabs. Before cutting out the
plate, place textured material along one side of the clay
slab and gently roll into the clay. Once the material is flush
with the top of the clay, peel it away. Clay is great for
picking up the most delicate details and is quite beautiful
at this stage.
With texture along one side of the slab, place the paper
plate templates so that the location of the design will be
pleasing on a plate. Remove excess clay and smooth the
rims of the plates, working on the top edge and then flipping the clay to finish the bottom edge of the rim. Sandwich the clay between two paper plates and press the clay
into the bottom corners of the lower plate. Remove the
top plate and paint a generous amount of contrasting slip
over the textured area. Leave the clay in the bottom paper
plate and let dry until it is a very stiff leather hard. The
amount of time varies depending on climate inside the studio. At this stage, use a metal rib to scrape away the top
layer of colored slip leaving behind only what is inlaid
into the textured areas.
Paper Stencils
Use paper stencils on leather hard clay after clay is placed
into the paper plate mold. I encourage beginning students
to make twice as many plates that they hope to end up
Interesting Texture Materials
Texture Ideas
Gently roll the following into your plate with a
rolling pin:
• Corrugated Cardboard
• Bubble wrap
• Lace remnants
• Mesh produce bags
Stamping Ideas
The following items can be pressed like stamps
into the clay but don’t do well under a rolling pin:
• Small plastic toys such as animals
• Beaded necklaces (I like the bathtub
drain chain, but be careful not to go too
deep with this or it can act like a perforation
and give your plate a long crack.)
with to keep them from overworking any one plate. Besides, they learn so much from the results of the larger
sample.
Each paper stencil can easily be used two times, and
with care, up to four times. Keep a copy of the original
design. I recommend students prepare by cutting as many
stencils as required before beginning the slip work. Trim
stencils so that there is about two inches of paper around
design. Soak paper in water until wet but not soggy and
then set onto paper towel to remove excess moisture. Position stencil and press down with a damp sponge. Paint slip
over design then remove paper stencil. If the stencil is too
dry to adhere to the next plate, repeat soaking. Sometimes
the stencil can be directly transferred to the next plate and
pressed with the sponge.
•
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Pinch, Slab and Coil Project:
Handbuilt Spherical Teapots
by Ron Korczynski
Spherical teapot, 9 in. (23 cm) in height, underglaze decoration with clear overglaze fired to cone 04,
by Ron Korcyznski. The teapot form easily lends itself to a wide range of creative expression, and
handbuilding a round teapot frees the clay artist from the symmetrical mechanized look of the wheel.
T
eapots are one of the greatest challenges for any
studio potter. Many elements go into their production and all the parts—the body, lid, handle
and spout—need to fit together into a cohesive
whole. For centuries, teapots have been produced in
myriad ways and forms, and like many potters, I initially
began making teapots on the wheel. But throwing and
putting the parts together was a challenge for me because
the forms were too mechanical so I began to experiment
with handbuilding. Since I’ve done a lot of handbuilding
using hump molds, this seemed the logical path to take.
While the process here uses a spherical form, you’ll soon
recognize the endless possibilities with other shapes.
“I cannot explain my enjoyment of clay. It is
difficult to put into words the feel of the clay in
my hands, the growth of a pot as it changes from
a shapeless mass into a vessel, the look of the dry
glazes as I decorate, the touch and visual experience of the pots as they come from the kiln.”
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Ron Korczynski
5
Getting Started
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2
3
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5
6
Each teapot begins with a slab draped over a plaster hump
mold. I make these round plaster hump molds by taking a
Styrofoam ball and cutting it in half. Styrofoam spheres are
available in a variety of sizes from craft supply stores, and
you’ll need a 6-inch ball for a modest-sized teapot. Other
forms can also work and I use the blue extruded Styrofoam
board found at home centers to build up and carve molds.
Once the shape is finalized, I glue it to a piece of wood
or tempered hardboard that’s been cut to shape (figure 1).
Tip: You can finish the mold by propping it up and pouring
plaster over the top. This gives you a thin, durable, absorbent layer that can be smoothed out when dry and makes a
great lightweight mold.
The Sphere
Roll out a slab that’s about ¼ to 5⁄16 inches thick. Apply
toilet paper to the mold as a release and place the slab
over the mold.
Trim the bottom, remove and repeat for the second
hemisphere (figure 2). Set the hemispheres aside and allow them to dry to the leather-hard stage.
Roll out a coil and attach it to the edge of one hemisphere (figure 3), then attach the other hemisphere using
your finger or tool to work the seam (figure 4).
Use a Surform tool to refine the shape (figure 5). Since
I do a lot of painting on my surfaces, I use a metal rib to
smooth the sphere (figure 6), but you can add different
textures at this stage.
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7
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All the parts of a
teapot—body, lid,
handle, foot and
spout—need to
fit together into a
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cohesive whole.
18
Many teapots can be made using this technique, and the
handbuilt sphere can form the basis for a variety of vessels or sculptures. The possibilities are endless.
Base and Lid
To create a base, one method I like is to use a triangular
trimming tool to cut a strip from a block of clay (figure 7).
With the sphere resting on an empty plastic container,
attach the base and add decorative elements according
to your style (figure 8). Of course, design opportunities
abound here but bear in mind that all parts on a teapot
work to form the whole work.
For the lid, cut a round opening in the top of the sphere
and set it aside. In order to have the lid fit only one way,
make a small notch in the opening (figure 9). Place toilet
paper around the edge of the opening as a separator. To
construct the lid, first place a small ball of clay in the
notch (figure 10), then add a coil of soft clay to fit into
the lid opening (figure 11) so it slightly overlaps the open-
ing. Take the clay piece you removed to make the opening
and attach it to the coil (figure 12). Flip the lid over and
add a ball of clay to the underside of the lid (figure 13).
This will add some weight and balance to the lid to help
hold it in place when pouring tea.
Spout and Handle
To form the spout, flatten a cone of clay (figure 14) and
form a spout around a brush handle (figure 15). Trim the
spout and attach it along with decorative elements to the
teapot (figure 16). To create the handle, I create two “dog
bone” shapes and flatten them, leaving some thickness at
each end (figure 17). Assemble the handle and add a decorative element if desired. Add a handle to the lid following
the same style (figure 18).
•
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8
Throwing: A Three-Stage Approach
by Jake Allee
W
hile conducting a workshop at the “Clay on
the Wall” symposium at Texas Tech, someone
asked the question, “How do you approach teaching
people to throw on the wheel?” This is a good question
and it’s something I’ve thought about often. I’ve always
held that all people have a mechanical intelligence related
to manual dexterity as we all have cognitive intelligence.
People have different aptitudes that translate into or affect their manual dexterity.
Over the last several years, I’ve focused my teaching efforts on catering to all of these dispositions and to different learning styles with the goal of helping students learn
and develop good habits. After all, learning to throw on
the wheel is about developing habits and you want the
student to develop good habits first. I personally know
what it’s like to feel the frustration of having to relearn
something after developing a bad habit, because I’m
learn things slowly to begin with. The following should
help you get quicker results from all your students.
Many educational workshops use a lot of buzz words
and philosophical concepts to identify and measure
learning styles, but what a clay instructor needs is a simple “nuts and bolts” method for attacking the problem.
I resolved to strip down the basic learning methods into
three categories and attack them individually in three
matching stages through my teaching:
excitement and raw energy to learn! I believe when the
students are called upon to refer to information they’ve
learned in stages 1 and 2 while engaging in stage 3,
they get a phenomenon educators call “completing the
circle.” When you complete the circle you are being as
efficient as possible with your efforts toward teaching
and directing the students to do the same with the act
of learning.
Stage 1: Readings and Visual Diagrams
This first category of learning methods, and the first
stage in teaching throwing, is often ignored by the
teacher because it takes work up front, and as educators we’re already buried in paperwork! However,
the extra time used for preparation pays off and the
students will be quicker to meet you half way.
A worksheet designed to address all the critical points
associated with habit forming for wheel throwing
technique helps. I always begin by asking the students
to read the worksheet through and I then present them
with several questions to make sure they have read it.
After that, I go over the content of the worksheet again,
re-phrasing it with words that come more naturally.
Any worksheet that addresses frequently asked questions can be used as a reference point by the students
and ultimately make your job easier. A worksheet
never takes the place of a verbal explanation from the
Stage 1. Readings and visual diagrams
instructor or a practical demonstration, but it certainStage 2. Practical demonstration and use of technique
ly gives the student something to think about when
Stage 3. Hands-on experience
it’s placed in their hands, even if they’ve walked into
the classroom late. The worksheet always reinforces
Obviously hands-on experience is the part we quite
stages 2 and 3. Flying solo with a worksheet for one
often throw our students at first, and we answer quesclass might make a student think about showing up on
tions after mistakes are made. However, reinforcement time. Revisiting the handout prior to practical demonof information introduced first through readings and di- stration at the beginning of the next class will elimiagrams then through practical demos is the best way to nate your feelings of guilt and give the late student a
see results at stage 3. Using the three-stage process calls chance for redemption.
upon the student to assimilate information in a manner
that they don’t normally associate with art making, yet
are familiar with through other subjects. As a teacher,
After everyone has read the worksheet and I reinforce
prioritizing these stages in learning a process in order
and explain it verbally, I move to stage 2. The students
from 1 to 3 is key to a student’s success, because they
watch the practical demonstration while reference to the
have the “blinders” on and will always prioritize them
worksheet throughout the process. I slow way down and
in the opposite direction, from 3 to 1 due to honest
ask the students how I should be executing the tech-
Stage 2: Practical Demonstration
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9
nique according to the worksheet. I
demonstrate all of the steps listed to
further reinforce the information. At
this time I also talk about some of
the “tricks” in my personal approach
for success.
If I make a mistake in the process
while demonstrating, we discuss
what happened. I encourage the
students to ask the following
questions. WHY did the mistake
happen? WHAT should have been
done differently? HOW can the
mistake be corrected? This shows
students how to learn from the
inevitable mistakes. They also refer
to this experience of watching a
demonstration, and the troubleshooting that occurred, when
working on their own pieces, so it
helps and influences them as they
form their own habits. Lastly, it
also puts them at ease with the
expert imparting the knowledge.
The first piece I make for a demo
is always destroyed at the end; this
takes away the preciousness of
the object created. I then take the
opportunity to give my short talk
on how each person in the class
dictates what is considered their
first piece on the wheel. Will it be
the piece that becomes an ashtray,
or will it be the piece that is kept
after they understand the control required to make a thin wall and keep
the piece centered? The viewer may
never know if the maker’s first piece
was made on the very first day or at
the end of the first year of practice.
Stage 3: Hands-on
Experience
everyone is ready. Once everyone
gets to the point of pulling up on
the cylinder, they are all cut loose
and begin to work on their own.
At this point I walk around and
address all of the students one-onone, giving suggestions and helping
with the challenges they encounter.
The whole process takes me about
an hour to go through from start to
finish. I always start the next class
with a review through practical
demonstration and check that everyone has their worksheet with them
for reference.
This approach may not work for
all teachers, but the idea is to teach
from as many angles as possible
and use each angle to reference the
other. Think about adapting this
method to your particular way of
teaching. Look at the effort Val
Cushing has put into point #1—the
achievement of his students speaks
of the value of his efforts. To the
students reading this, please use
this information to pull knowledge
from your teacher in a way that
best fits your learning style, I’m
sure he or she will direct you to a
good resource even if there’s no
worksheet available. Remember,
the classroom environment is a
50%–50% situation with regards
to effort, requiring equal amounts
from both student and teacher.
Realizing this helps speed everyone
to what really counts, THE CONTENT OF THE WORK. Technique
is only the path to content and
work ethic will drive you down
that path! GOOD LUCK! n
Creating a Teaching Worksheet for Ceramics
#1
Identify the basic steps in the technical process.
Double check the descriptive language used to convey these steps.
#2
Develop drawings or high-contrast photographs as visual examples to these steps.
All diagrams should be clearly labeled and the images should photo
copy well.
#3
Identify and address frequently asked questions.
#4
Leave the “tricks” out and let that be a point of interest with the practical demonstration.
When I finally make it to Stage #3,
everyone is ready to get started. I
ask for one more exercise of patience on the student’s part. Everyone goes through the steps of centering and opening simultaneously and
no one moves to the next step until
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10
Throwing on the Wheel
by Jake Allee
Tips for success
 Always apply and release pressure to
the clay slowly.
large arrow indicates hand to clay contact area when
throwing. Small arrow indicates wheel direction.
 Never allow water to collect in the bottom of the piece.
right
handed
 Slow the wheel down in each step of
the process.
 Be persistent in your efforts.
left
handed
cenTering The clay
 Start with a well wedged ball of clay
that’s no larger than the size of your
hands.
diagram illustrating hand to clay pressure.
Anchor your elbows to your knees for
stability.
Wet your hands and the clay.
Slowly apply downward pressure
equally to all sides of the clay until no
movement exists within the mass.
clay profile
wheel head
When the clay is “centered,” it will be
spinning while your hands remain still.
Once the clay is centered, relax and
slowly pull your hands away.
©2009 Ceramic Publication Company
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opening up The clay
Place the tip of your thumb in the center of the
clay mass.
Slowly roll your thumb into the center of the
clay maintaining pressure on the clay profile.
Stop ½ inch from the wheel head.
To create a flat bottom, use the same hand position and pull straight back toward yourself.
Any movement causing the piece to go out of
“center” is reflected in the rest of the piece.
thumb
clay profile
making a pull
thumb
From this point on, manipulate the piece only
at the 3 o’clock position relative to the wheel
head (9 o’clock if left handed).
wheel head
large arrow represents thumb movement. Small
arrows indicate hand to clay pressure.
Slowly apply and release pressure.
thumb
Always use your fingertips when making a
vertical pull and slow the wheel down.
clay profile
wheel head
flat bottom profile with arrow representing thumb
movement.
handS
Position your inside finger slightly above the
outside finger and apply pressure with the outside finger slowly moving your hands upward.
When making a vertical pull, pull the clay
inward to create the volcano shape.
Repeat the pulling process until the wall is uniform in thickness from top to bottom.
clay profile
wheel head
illustration showing fingertip to clay pressure
points and direction of vertical pull.
clay profile
volcano profile
©2009 Ceramic Publication Company
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12
How to Glaze
Photos of finished pieces by Harrison Evans.
by Annie Chrietzberg
glazing tricks
“Auntie Myrtle: A Covered
Dish.” Glazing complicated
pieces requires pouring,
dipping, and brushing of
glazes. Practicing with
various techniques ensures
greater success with
each piece you complete.
G
tured elements, I use a combination of pouring, dipping
and brushing to get the color where I want it. Dipping
is the easiest way to ensure an even application, and
pouring, with a little practice, is the next. Brushing takes
more practice, time and attention, and I only use it when
the first two methods are not options for a tricky place
on a pot.
The two troublemakers involved with glaze application are water and gravity. When a bisque pot becomes
Process photos by Jonathan Kaplan.
lazing, for a lot of people, is the bane of their
ceramic lives. While there’s no specific glazing
system that fits everyone’s needs and preferences, the
more information you have allows you more options
when you get into a glazing corner. My system for
glazing evolved with my own body of work, and as the
work changes, I draw on various aspects of it to suit
the particulars of the pieces in front of me.
For complex forms consisting of thrown and tex-
1
2
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3
4
5
6
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too saturated with water, it won’t accept glaze correctly,
so use the least amount of water possible when glazing,
including when you are making corrections. And as for
gravity, I doubt there’s anyone who hasn’t experienced
the wayward drip of one glaze flowing toward the earth
across the perfect application of the previous glaze.
• Use a damp sponge instead of rinsing, which should be
kept to a minimum. Wring the sponge thoroughly and
rotate it so each area is only used once. I tend to use half
a dozen or so of those orange round synthetic sponges
during any given glazing session (figure 4).
• Glazes must be well mixed. I use an electric drill with
a Jiffy Mixer attached (figure 5). If there is dry glaze
caked on the sides of the bucket, sieve the glaze, then
• Keep bisqueware clean. Lotions, or even the oils from
return it to a clean bucket.
your hands, can create resist spots where glaze adheres
• Glaze all the interiors of your pots first by pouring the
unevenly or not at all. Throughout all phases of the glaz- glaze in, then rolling it around for complete coverage.
ing process, including loading and unloading the kiln,
For complex pieces requiring a number of glazing steps,
handle bisqueware with a clean pair of disposable gloves
glaze the insides the day before to give you a drier
(figure 1). If you think your bisqueware has been compro- surface to work with, especially for brushing (figure 6).
mised—splashed with something, covered with grime, or
• When removing unwanted glaze, scrape off as much of
maybe handled by a visitor—bisque it again rather than
it as you can with a dental tool or a similar small metal
risk a crawling glaze.
scraper to keep a sharp line. A damp sponge removes
• Remove all dust before glazing including bisque dust,
the remaining glaze with a few strokes, keeping water
studio dust and even household or street dust. Use an
usage to a minimum (figure 7).
air compressor for foolproof results, but work outside
• Use a stiff brush to help clean glaze drips out of
or in a well-ventilated area away from your primary
texture (figure 8).
workspace, as bisque dust is extremely abrasive to your • For dipping glazes, select an appropriately sized
lungs (figure 2).
container for the work at hand. I have lots of different
• Use silicon carbide paper to remove any rough spots you sizes of shallow bowls that are perfect for dipping the
missed before bisque firing. Place your work on a piece of
sides of my pieces. Wide shallow bowls allow me to see
foam to prevent chipping. After sanding, wipe with a damp what I’m doing, so I even use them for smaller things
sponge to remove all traces of sanding dust (figure 3).
that fit into the glaze bucket (figure 9).
Tips for Success
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Brushes
I use sumi brushes, which have
long bristles that come to a
point, but in the past, I have also
used hake and multi-stemmed
hake brushes for large areas.
Experiment with all the long,
springy-bristled brushes. Mop
brushes might work for you,
but don’t buy expensive watercolor brushes. Applying glaze is
a cruder application than watercolor, and an expensive, fine
water-color brush won’t work as
well for a glaze as a cheap hake
from the ceramic supply store. A
brush with long, springy bristles
that come to a point is best. Successful brushing not only relies
on technique of application, but
also the glazes you’re using and
the temperature you’re firing
to. Some glazes lend themselves
well to brushing, while others
are more finicky. Make wide tiles
representative of your surfaces
and use them to test how well
your glazes take to brushing.
• When you can’t dip or pour, it’s
time for brushing. Watch your
bisque as you brush—glaze is shiny
and wet when first applied, then
becomes matt as the bisque absorbs
the water. If you recoat too soon
over a damp coat, you’ll move
the foundation layer rather than
imparting a second coat (figure 10).
• Consider gravity when brushing
and hold the pot both to encourage
the glaze to go where you want it to
and to keep it from running where
you don’t want it (figure 11).
• If a drip flows onto a previously
glazed surface, stop, set the pot
down and wait. Resist the urge to
wipe the drip with a sponge. Let the
drip dry, then carefully scrape it off
with a dental tool or metal rib. Use a
small compact brush to wipe away
glaze in areas you can’t reach with a
sponge (figure 12).
• Don’t brush glaze from the big
glaze bucket. Pour a small amount
into a cup, then briskly stir it occasionally to ensure that it stays
properly mixed. Keep a large, damp
sponge nearby to keep the brush
handle clean. Stray drips often
start with a handle full of glaze
(figure 13).
If you’re glazing pots that don’t
have a defined foot, push them
across a piece of 220-grit silicon
carbide sandpaper. The sandpaper
removes some of the glaze from the
contact areas, indicating where you
need to wipe off the remaining glaze
(figure 14).
•
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15
10 Hot Kiln Tips
by David L. Gamble
I
conduct a lot of workshops
for K–12 teachers around the
country every year and I’m
thrilled about the enthusiasm educators have for teaching ceramics to
kids. Throughout these workshops
I answer many questions and hear a
lot of stories on the subject of firing,
especially of electric kilns.
There are two main reasons for
firing clay, and in most cases two
different firings are required. One
is to prepare pieces for glazing by
firing what is called a bisque. In
this firing, the heat from the kiln
changes the molecular structure of
the clay and hardens it so it will no
longer break down in water to its
original moist, pliable form. This
also makes pieces less fragile, but
still porous enough to absorb water
so that when wet glaze is applied, it
will stick to the surface. The second
firing is to melt and fuse any applied
glaze to the surface and for higher
temperature firings, this firing further strengthens the pots.
Ten Tips for
Successful Firing
1
Before you fire. When installing your kiln, make sure it’s at
least 18 inches away from any wall.
Vacuum the interior of the kiln,
especially the element grooves (figure
1), about every 20 firings, and after
every firing when a piece blows up in
the kiln. Inspect hinges and handles
for wear (figure 2). Check the
thermocouple(s), and replace if necessary (figure 3). Every six months,
unplug the kiln (if your kiln has a
plug) and inspect the prongs as well
as the insulation (figure 4). Brown or
1
Vacuum the interior of the kiln, especially the element grooves.
3
Check the thermocouple(s), for excessive oxidation.
4
Unplug the kiln and inspect the
prongs and insulation.
2
5
Inspect hinges and lid handles for
wear. Tighten loose screws or pins.
Inspect kiln shelves and reapply kiln
wash to any bare spots before firing.
black discoloration indicates a worn
plug or loose wires and a potential
fire hazard. Keep all flammable,
combustible and meltable materials
(cardboard, wareboards, newspaper,
fabric, vacuum hoses, plastic, etc.,)
away from the sides and top of the
kiln. These areas get extremely hot.
Protect your shelves. Kiln wash
protects your shelves from glaze
drips. Inspect shelves prior to firing
and recoat any bare spots or recently cleaned and scraped shelves as
needed (figure 5). Remove any loose
or chipped kiln wash that make
flake onto pots during the firing.
Store unused shelves in a safe and
low-traffic area.
Always use cones. Pyrometric cones are formulated from
2
3
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6
Remove burrs using a damp sponge
or drywall sanding screen before the
bisque firing.
ceramic materials including clay,
oxides, feldspars, and frits, and are
designed to bend at specific time/
temperature combinations to give
you an accurate reading on the heatwork created in your kiln. Cones
measure the relationship of temperature absorbed by the ware over
time. Tip: Use cones even if you are
using an automatic kiln controller.
Cones verify the accuracy of the
controller.
Clean up greenware. Signatures
and decorations leave burrs
that must be removed using a damp
sponge while leather hard, or drywall sanding screen for drier work,
before the bisque firing (figure 6).
Once fired, the only way to remove
these is by grinding with a Dremel
tool, or sanding with wet/dry silicon
carbide sandpaper.
Handle greenware with care.
Bone dry greenware is fragile—
more fragile than when it’s leather
hard. Never pick up pieces by any
appendage or handle.
Fire dry pots. To see if a pot is
dry, touch the pot to your cheek
(figure 7). If it is cold or damp, there
is still moisture in it and you will
need to preheat the kiln to 180°F
and leave it at that temperature and
vented until all moisture its gone.
Water boils at 212°F (100°C), and
that’s the temperature where there’s
danger of blowing up pieces. If the
moisture is not driven out and the
temperature rises to water boiling
levels, the rapid expansion of the
steam that’s created blows out the
walls of your piece.
Wipe your feet. Any glaze that
touches the shelf during a firing
sticks to it. Carefully sponge off any
glaze within ¼ inch of the bottom
of the foot. For pots with thick or
runny glazes, clean off a bit higher
than that. Do not rely on the kiln
wash to save the pot or the shelf
from being damaged by glaze drips
(figure 8).
4
7
A pot that feels cool to the touch still
has moisture in it and needs to be
preheated before firing.
5
6
8
Sponge off any glaze within ¼ inch of
the bottom of the foot.
7
9
Stagger the shelves and place taller
pots in the middle of the kiln to promote better heat penetration. Allow 5
inches of clearance when placing large
flat work on the top shelf.
8
Loading greenware or glazeware. Electric kilns heat from
the outside walls, where the elements are located, in towards the
center, so stagger the shelves and
place taller pots in the middle of
the stack to promote better heat
penetration to the middle of the
kiln. Greenware pieces can touch
and can be stacked in some cases,
but I prefer to leave space between
them for even heat distribution.
When placing a large flat piece on
the top shelf, allow approximately 5
inches of clearance to the top. Extra
clearance allows for heat from the
sides of the kiln to travel up and
over, reaching the middle of the
piece so that all areas heat evenly.
If wide pieces are heated unevenly,
the expansion rate of the side may
be considerably different from that
of the center of the piece, which will
cause it to crack. In all firings, keep
a the edge of the stack at least 1
inch from sides of the kiln (figure 9).
Bisque fire slowly. Clay contains
organic material that needs time
to burn out. If you raise the temperature of the kiln too fast, gases will
become trapped in the clay body.
Organic materials burn off between
572°F (300°C) and 1472°F (800°C).
Also, if not completely burnt out in
the bisque, organics may give you
trouble in the glaze firing as it as
escapes as gas, pushing through the
glaze and creating pin holing, which
can mar the glaze surface.
Keep records. Keep a firing record of firing times
(lengths), the cones you used and
the result of their melt (draw a
quick sketch of how they looked,
or note whether the target cone was
at 1, 3 or 5 o’clock for example),
and record the number of firings
in a particular kiln. These records
can give you indications on element
wear (e.g., if firings take longer than
usual) and future maintenance that
may be needed. n
9
10
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17
CLAY STUDIO:
TAKING IT BEYOND
THE CRAFT
RINGLING COLLEGE OF ART AND DESIGN’S
WILDACRES ART WORKSHOPS is an exceptional
retreat experience that provides an environment
for creative exploration and camaraderie.
Each concentrated week of classes,
demonstrations, critiques and artists lectures
offers extensive time to focus on your work,
cultivate new ideas and to develop new skills.
Small class sizes ensure individual attention to
your work and creative goals.
Upon completion of a weeklong workshop,
participants may earn 2 or more CEUs.
WILDACRES ART WORKSHOPS 2012 • BLUE RIDGE MOUNTAINS, NORTH CAROLINA
JULY 15-22. JULY 22-28. OCTOBER 22-28
ONLINE: www.ringling.edu/cssp
PHONE: 941.955.8866
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