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                           TECHNICAL PAPERS #14
                       UNDERSTANDING THE SMALL-SCALE
                         CLAY PRODUCTS ENTERPRISE
                              Miska Petersham
                            Technical Reviewers
                               Daniel Rhodes
                               Gerald Rowan
                       1600 Wilson Boulevard, Suite 500
                        Arlington, Virginia, 22209 USA
                    Tel:  703/276-1800 * FAX:   703/243-1865
             Understanding the Small-Scale Clay Products Enterprise
                            ISBN:   0-86619-214-X
                 [C] 1984, Volunteers in Technical Assistance
This paper is one of a series published by Volunteers in Technical
Assistance to provide an introduction to specific state-of-the-art
technologies of interest to people in developing countries.
The papers are intended to be used as guidelines to help
people choose technologies that are suitable to their situations.
They are not intended to provide construction or implementation
details.  People are urged to contact VITA or a similar organization
for further information and technical assistance if they
find that a particular technology seems to meet their needs.
The papers in the series were written, reviewed, and illustrated
almost entirely by VITA Volunteer technical experts on a purely
voluntary basis.  Some 500 volunteers were involved in the production
of the first 100 titles issued, contributing approximately
5,000 hours of their time.  VITA staff included Leslie Gottschalk
and Maria Giannuzzi as editors, Julie Berman handling typesetting
and layout, and Margaret Crouch as project manager.
Miska Petersham, the author of this VITA Technical Paper and a
second one, "Understanding Clay Recognition and Processing," has
worked in the field of ceramics for many years.   He is also a
designer in glass and wood and a wood carver, and has considerable
experience in these fields in developing countries.   Reviewers
Daniel Rhodes and Gerald Rowan are also experts in clay and
ceramics.  Daniel Rhodes is a professor emeritus at Alfred University,
New York, in ceramics.  He is the author of four books on
ceramics, and has experience with pottery design, glazes, kilns,
molds, clay refining, etc.  Gerald Rowan is the chairman of the
art department at Northampton Community College, Pennsylvania.  He
has a wide knowledge of ceramics, clay, brick making, kiln building,
glazes, owner made equipment, etc.
VITA is a private, nonprofit organization that supports people
working on technical problems in developing countries.   VITA offers
information and assistance aimed at helping individuals and
groups to select and implement technologies appropriate to their
situations.  VITA maintains an international Inquiry Service, a
specialized documentation center, and a computerized roster of
volunteer technical consultants; manages long-term field projects;
and publishes a variety of technical manuals and papers.
                 By VITA Volunteer Miska Petersham
People discovered bow to use clay over 20,000 years ago.  The
basic principles of shaping, drying, and firing clay are still
the same today as they were then.   The only significant changes
since the discovery of clay have been the identification of
additional clay materials and improvements in the methods of
making clay products.
Every age has left behind objects made of clay.   Before the introduction
of plastics and sheet tin, most containers for food--whether
in solid or liquid form--were made of clay or glass.   Clay
was also used for architectural decoration as well as structural
material, for it was plentiful and long lasting.
Although the introduction of new materials and techniques has
reduced the use of clay in many areas, clay still plays an important
role.  It is a versatile material that can be used at all
levels of technology.  It is common in most parts of the world,
and it is possible to collect and use it for some types of
products without large capital outlays.   Yet, in many developing
countries, it is an underutilized resource.
Ceramics is the general term for manmade products shaped from any
natural clay material and transformed into a permanent hard state
by heat.  The term includes:
     *   Pottery and porcelain consisting of such articles as porcelain
        dolls, dinnerware, sanitary ware (toilets, sinks,
        etc.), cookware, and flowerpots.  Pottery is defined as
        ceramic ware, especially earthenware and stoneware, which
        refers primarily to container forms (e.g., pots, vessels)
        often made from low-fired red clay.  This definition,
        however, varies greatly from place to place.  Hollowware
        and giftware are terms used when referring to dinnerware
        and decorative items such as ashtrays and small sculptures.
     *   Structural and industrial ceramics consisting of a wide
        range of articles used in building and industry.  Bricks,
        tiles, and sewer pipes are some examples of structural
        ceramic products.  Sparkplugs, insulators, furnace linings,
        etc., are some industrial ceramics.
The weathering of igneous rock (rock of volcanic origin) over
long stretches of geological time causes the formation of clay
minerals.  This rock is usually feldspathic (i.e., it contains
mostly feldspar) in temperate areas and on large continental land
masses, whereas in tropic volcanic areas where little or no
feldspar exists, it is usually basaltic (i.e., it contains mostly
basalt).  The different geographic locations, source materials,
and climatic (weathering) conditions produce different combinations
of clay minerals and different kinds of impurities which
result in the different working characteristics of the clays.
Most clay is made up of several clay minerals, which are similar
but have different working characteristics.   Although one cannot
see with the naked eye what clay minerals are present and in what
proportion, experienced ceramists usually can guess the workability
of clays by observing their handling and firing properties.
Determining precisely what minerals are actually present requires
expensive, careful, and elaborate laboratory analysis--but even
this is subject to error.
Kaolin ([A1.sub.2.O.sub.3]/[2SiO.sub.2]/[2H.sub.2.O]) is the most common clay mineral, but
pure kaolin deposits are a rare find.   These deposits, when found,
often have commercial value because their use in industry is not
limited to ceramics.  Pure kaolin is white, non-plastic, and
highly refractory (refractory clays are ones that resist heat and
do not melt when they are subjected to high firing temperatures).
It is called a primary clay, because it is clay found where it
was formed.
Most clays are predominantly kaolin mixed with other clay minerals
and impurities such as iron, manganese, mica, silica, and
rock fragments.  The different mixes and proportions affect the
working properties of clays, causing them to vary in their behavior.
Some clays are suitable for one kind of product only, others
have broader uses, and still others are totally unusable.  The
only sure way to determine the workability of a particular clay
is to make the desired product on a trial basis and analyze the
results.  This kind of practical test is much more satisfactory
for most operations than the more complicated laboratory testing,
which should be undertaken only after a clay or blend is deemed
Red clays are most commonly found in deposits on or near the
surface of the earth.  They are called secondary clays because
they have been eroded and carried from their primary source by
frost, rain, or water bodies, to become huge sedimentary deposits
at the bottom of lakes and seas.   As they are borne along, these
clays come into contact with other natural substances, such as
sand, calcium, and iron compounds.   Red clays contain various
impurities, which lower the clays' resistance to heat, making
them suitable only for earthenware.   Earthenware clay is usually
dark red, very plastic, and fires at a relatively low temperature.
Many clays fall between kaolin (the purest clay) and red clay
(the least pure clay) in their working properties, and each clay
must be tested individually to determine its usefulness.  Some
general differences exist between clays found in temperate regions
and those found in tropical volcanic regions.   These differences
are the result of changes in the proportions of clay minerals
and impurities.  The principal differences between the two
clays are outlined in Table 1, generally indicating the extent to
which clay deposits must be examined for suitablility.
         Table 1.  Reliability of Temperate Clays
                   Versus Tropical Volcanic Clays
                         Distance     Degree       Quality     Consis-
Type of     Origin of      Clay          of          of         tency
Clay          Clay       Traveled     Weathering    Clay Mix   of Clay
Temperate   From feld-     Long       Slow         Well-    Relatively
            spathic rock              weathered    mixed    the same
                                                           in many
Tropical    From basal-    Short      Fast          Poorly   Many
Volcanic    tic rock       to         weathered    mixed    variations
                           none                            even in one
Although all deposits should be checked carefully for consistency
and content, this holds true especially for clays found in the
tropics.  Tropical clays can be used to make some kinds of clay
products, but they are often more difficult to use and require
much more skill and care.
If you paln to produce large quantities of clay objects, you
should be sure that there is a sufficient reserve of clay of the
same quality to last a minimum of 10 years.   The clay should be of
sufficiently high quality to produce the desired product.  When
purchasing clay, costs may vary from a few cents to 20 or 30
cents per pound.  You should consider 10 to 15 cents a maximum.  In
an area where producers must gather and process their own clay,
all associated costs must be taken into account.
Clay can be processed either at a plant designed for one clay
manufacturer or at a processing plant that serves several manufacturing
operations.  Clay is mined and its impurities removed;
it is then ground if necessary, bagged, and stored in moist
plastic form or as dry powder called clay flour.   Removal of
transported impurities from the clay is done either in the clay's
wet or dry state, depending on the original material, amount
needed, costs, and use.  The dried, refined clay is then mixed
with other clays or additives, such as feldspar, to produce the
desired clay body (a clay body is the prepared material from
which any ceramic article is made).
As in all industries, the ceramic industry has developed its own
clay terminology over the years.   In the sections that follow,
some of the most common terms relating to various clay processes
are defined.  Almost all of these processes may be done by hand,
by simple foot-powered machines, or by complex mechanically powered
machines.  Generally, both the cost and the quality of the
clay product go up as the sophistication in technology increases.
In the case of large-scale mass production of one item, the cost
per item generally decreases, given that the demand for the item
is high.
Clay Preparation
Clay bodies are a mixture of one or more natural clays plus such
other materials as feldspar, silica, etc.   Clay bodies are prepared
in a liquid state for slip casting; in a semi-solid state
for plastic forming, and in an almost dry state for dry pressing.
Clay-Forming Techniques
Potters shape clay in a number of ways.   Some popular shaping
methods are described below.
     *   Throwing is the act of turning a lump of semi-solid clay
        on a potter's wheel.  The clay is "thrown" (shaped) on the
        wheel while the wheel turns.
     *   Jiggering is a highly mechanical method of making
        tableware.  In this process, a lump of semi-solid clay is
        placed on a convex plaster bat and turned while a
        template is held against it.  As the plaster bat turns,
        the clay is squeezed into shape.
     *   Extrusion involves pressing out a lump of semi-solid clay
        through a forming die.
     *   Pressing involves pressing a lump of semi-solid clay into
        a mold.
     *   Slip casting involves making slip (liquid clay) and pouring
        it into a dry plaster mold.  The plaster absorbs
        water, forming a skin of drier clay on the mold surface.
        When the liquid is poured off, this skin is left, taking
        the same shape as the mold.  The clay body is mixed with
        water to make slip but this ordinary slip is almost
        impossible to use due to excessive shrinkage.  To make it
        work better, one or more deflocculants (water softeners)
        such as sodium silicate are added in very small amounts.
        This decreases the water necessary to make the slip
        liquid and therefore reduces the shrinkage, which allows
        it to be cast.  Many clays are not suitable for casting
        due to difficulty in achieving deflocculation.  Only a
        practical test of the casting properties will tell.
     *   Plastic forming: Before semi-solid (plastic) clay can be
        formed by whatever method, it should be mixed (kneaded)
        to obtain an even consistency and eliminate trapped air.
        This can be done by hand, by foot, or by machine.  In most
        new plants, a mix muller to crush and mix and a vacuum
        pug mill to de-air and prepare clay are used.
     *   Dry pressing requires extremely high pressures and a
        carefully-controlled moisture content.  Because of the
        need for expensive equipment, dry pressing is best suited
        for large-scale production.
This section discusses the basic resources required to establish
various kinds of small-scale ceramic plants.   Before we proceed
with this discussion, it is important to note the following:
Opening and maintaining a small-scale ceramic plant is a complex,
demanding operation that requires a full-time commitment.
People should consider embarking on such a venture only if they
are sufficiently trained to make high-quality ceramic products,
and are capable of designing and building the basic ceramic
equipment necessary for making ceramic goods.   The traditional
apprenticeship for a ceramist is seven years.
A common error is the notion that anyone can set up a ceramic
business and be successful at it after only a few weeks of training.
Given that ceramic technology is relatively simple, setting
up a ceramic business looks deceptively easy.   Sound advice must
be sought from a qualified ceramic expert in order to succeed in
the ceramic industry.  The expert must have broad experience in
ceramic technology, design, and marketing, and must have the time
to study the local cultural and economic conditions before giving
Generally speaking, small-scale ceramic production progresses
from relatively simple technology to more complex technology as
demand, markets, and expenses increase.
Unsophisticated brick manufacturing can be done in a small plant
operated by one or more workers.   Setup costs are very low, but a
nearby clay source and cheap or free fuel are necessary.  Fuel can
be wood scraps, coconut husks, or similar material in abundance.
Total costs range from about $1,000 for basic equipment to
$10,000 for some good-quality, imported equipment.
The bricks can be formed in simple wood molds on the ground with
no elaborate processing equipment required.   For a more sophisticated
operation, simple hand-operated (lever-type) pressing machines
are available.  This improves both appearance and quality.
In most cases of small-scale brick manufacture no proper kiln is
used.  An open setting called a clamp makes use of the brick that
is to be fired.  By leaving open channels through the clamp, a
path for the heat is provided.   After firing, all or part of the
clamp is dismantled.  Often the walls containing the fire mouths
are left up and all other parts rebuilt after each firing.  It is
rare at this level that a regular pottery kiln is used since it
is needlessly expensive and holds a minimum of bricks.
For more sophisticated brick manufacturing, the costs rise with
increases in plant productivity and in the quality and quantity
of equipment.  The primary task here is to analyze the market, so
that production capacity can be consistent with demand for the
product.  Only after analyzing the market can any determination of
feasibility be made.  This paper does not attempt to provide estimates
on the cost of operating a sophisticated brick manufacturing
plant; to do so would be meaningless, since all aspects of
this type of operation are subject to local variation.
For a very simple, unsophisticated operation, the cost (excluding
building costs) should be about $15,000.   There are so many variables
involved that this cost is at best an approximation for
average conditions.  It is possible to hand-make tile of all kinds
at much lower cost, but these are not as readily accepted on the
market as more sophisticated tiles.   An exception is those areas
where the hand tradition is already well established and in these
cases the conditions of manufacture will already be well established.
Basic equipment items and their costs are given in Table 2.
    Table 2.   Estimated Equipment Costs for a Small-Scale
              Floor or Roof Tile Manufacturing Plant
                                                    Equipment Costs
Type of                                                (Dollars)(*)
Equipment                                           Local        Imported
Press and dies                                      1,000   to  10,000
Mix muller                                            500   to   3,000
Jaw crusher                                           800   to   3,000
Pug mill                                            1,000  to  10,000
Ball mill                                             500   to   5,000
Kiln                                                1,000   to  10,000
Miscellaneous small equipment                       1,000  to   5,000
Transportation (truck)                              5,000  to  15,000
(*) Costs will vary, depending on quality of equipment and where it
is purchased.
Note:  Processing equipment can often be built locally at considerably
less cost than that for imported equipment.
The type of hollowware product is the key to setup costs.  Fine
ceramics (e.g., china and porcelain) require highly refined kaolin,
feldspar, and silica, which are expensive.   These materials
may be purchased locally, if available, or abroad, in their
refined state; or they may be purchased in their unrefined state
and refined at the factory.  The setup costs will vary from operation
to operation, depending on the local set of conditions each
operation encounters.  For example, the need to import materials
could drive up the costs.
If ceramic materials are available locally, and do not require
extensive processing, or if less than top-quality ware is the desired
product, the setup costs can vary from $25,000 to $100,000,
depending on the type and quantity of products produced, and
whether the equipment is made locally or imported.
A small hollowware plant employing 10 to 15 people would have to
secure a large market for its products to warrant the excessive
setup costs of refining and processing ceramic materials.  Imported
processing equipment alone could cost over $100,000.
Plants already in existence in the Orient and some other areas
have been set up for much less, but it must be remembered that
the tradition, necessary skills, and market acceptance have been
there for generations.  In order to set up in an area without this
background, very different conditions may apply.   The costs are
considerably higher since there are many more difficulties to
For large-scale production of clay products such as dinnerware
and giftware, the setup costs can range from $100,000 to over $1
million.  Investments of that magnitude call for a careful analysis
of potential markets.
Specialty ceramics such as sparkplugs, insulators, or chemical
porcelain require a small- to medium-sized, highly sophisticated
operation, as well as a reliable source of high-quality kaolin,
feldspar, and silica.  The setup costs are therefore relatively
Simple ceramic technology was developed long ago by families and
guilds who would jealously guard from the public any new advancements
they had made in the field.  For this reason, the field of
ceramics was slow to change.   Only within the past 30 to 40 years
have new ceramic discoveries been made available to the public.
The public now has access to books and courses providing them
with a more open learning environment.   Despite the knowledge that
has been gained thus far, many aspects of ceramics are still not
completely understood.  Only through continuing research can we
broaden our understanding of the field to make better ceramic
products.  New findings spurred by research into high heat-resistant
materials continue to become available.
The advantages of the basic ceramic technologies over more advanced
technologies are that:
     *   ceramists with only minimal skills can produce pottery,
        brick, or tile easily because of the simplicity of the
     *   entrepreneurs need to invest only a small amount of capital;
     *   ceramists can produce ceramic articles from local clays
        and sell them on the domestic market.
The only disadvantage of the basic technologies is that they produce
low- to medium-quality products rather than top-quality products.
In order to improve significantly the quality of ceramic
products, entrepreneurs would need to invest in more sophisticated
equipment, as well as hire more highly trained workers.   To do
so, however, would increase both the initial and the operating
Choosing the size, location, and type of ceramic industry requires
careful consideration of all the facts.   There is no universal
formula.  Each case must be considered on its own since
there are so many factors to consider.
Even for a very small operation, some kind of feasibility study
by a qualified person should be undertaken.   That the person
chosen to perform the study be qualified is important, for getting
bad advice from a nonexpert can cost more in the long run
than getting sound advice from an expert at the very start.
Ceramic Equipment:  Domestic Versus Imported
Proper clay machinery is one of the keys to a successful operation.
For example, a simple ball mill capable of handling 100-pound
batches of clay can be built in-country if a good machine
shop is available.  This type of mill is unsophisticated, however,
and has a relatively short life of about five years.   On the other
hand, it costs about $500 to $1,000 and can be repaired locally.
The other extreme is to buy from the United States or Europe a
sophisticated mill, which does essentially the same job as a simple
ball mill.  Sophisticated ball mills last considerably longer
and require less maintenance, but spare parts are available from
abroad only, and initial costs are much greater.
Suppliers of ceramic equipment are located in industrialized nations,
and most of their equipment is built to order.   Because
these suppliers have very small inventories, if any, it may take
them as long as one to two years to fill orders for new equipment,
but there are few central clearing houses.   The best source
of information for used equipment is any large ceramic supply
house in any of the industrialized countries.
Equipment manufactured in the United States, Britain, and Europe
is well made, sophisticated, and expensive.   India produces ceramic
equipment that is sturdy, less sophisticated, and much cheaper,
but shipping and actual arrival of the correct piece of
equipment can be the source of many headaches.
Except for fire brick and setter slabs, which must be imported,
most equipment can be built locally if a qualified machine shop
is available.
In selecting equipment, careful consideration should be given to
energy requirements; the availability of present and future energy
sources; and current and future energy costs.
Clays:  Domestic Versus Imported
Refined clays can sometimes be imported at reasonable costs, but
in most instances the following reasons rule against imports:
     *   Reliance on an imported source could cause ceramic production
        to come to a halt if, for any reason, that source
        became unavailable.
     *   Costs to import are usaully somewhat higher e.g.,
        shipping costs are higher).
     *   Importation of clays impedes the selling of local materials.
     *   Importation of clays drains money out of the country.
     *   Importation of refined clays takes business away from
        local clay-processing industries.
Answering Important Business Questions
Anyone interested in earning a living from ceramic manufacturing--be
it a small-scale, medium-scale, or large-scale operation--should
know the answers to the seven sets of basic business
questions provided in this section.   Groups of questions are divided
into the following categories:   market survey, fuel source,
clay source, labor, equipment requirements, product design, and
business location.
Market Survey
1. What clay products are currently in use?
2. In what volume?
3. What is made locally?  What is imported?
4. What percent of the market does the local product represent?
5. What part of the market can you realistically fill?
6. If a new product is considered, what is the expected demand?
7. Is this a guess?  result of a survey?  general consensus?  other?
Fuel Source
1. Type desired?  (Usually gas, oil, wood, or sawdust; electricity
   is expensive as is the equipment required to produce it.  Fuel
   source and type of clay affect temperature ranges required to
   produce objects, which in turn greatly affects cost.)
2. Availability?
3. Cost?
4. Estimate of amount to be used?
5. Transportation (If wood or sawdust)?
Clay Source
1. Availability in proper amount?   (10-year supply minimum)
2. Cost to collect and process?   (Under 15 cents per pound to use)
3. Quality?  (Knowledge of test results and pilot products tried)
4. What imports are necessary?   (Should not be more than 20 percent)
5. What to import?  cost?  availability?
1. Trained locally?  how?  where?   cost?
2. Trained overseas?  availability?  cost?
3. Wage pattern, skilled and semi-skilled?
4. Relative productivity?
5. Trainability?  (i.e., conversion of nomadic tribesman to factory
6. Cultural consideration (i.e., low-class or caste occupation,
   sexual bias, etc.)
7. Training allowances?  (Usually six months to one year for general
   production personnel; and two to six years for foremen,
   technicians, and designers)
Equipment Requirements
1. Locally built?  (Possible with competent machine shop)
2. Imported?
3. What country?  (In the United States, Britain, Europe, and India,
   cost and quality vary)
4. Size and type needed?  (Generally requires expert help)
Product Design
1. Design quality?  (For successful market penetration, designs--especially
   giftware and hollowware--must be unique and of high
2. Design source?  In house or outside designer?
3. Cost?
4. Availability?
Business Location
1. Retail sales potential?
2. Transportation of raw materials (clay is heavy, and a large
   quantity is needed; it must also be stored for processing and
   use) versus transportation of finished product?
3. Availability of labor?
4. Zoning?
5. Access to shipping imports or exports?
6. Fuel source?
7. Pollution of environment?
American Ceramic Society Bulletin
American Ceramic Society
65 Ceramic Drive
Columbus, Ohio 43214 USA
British Ceramic Research Association
Queens Road Penkhull
Stoke-on-Trent, ST4 7LQ
Ceramic Industry and Brick and Clay Record
Cahners Publishing Company, Inc.
1350 E. Touhy Avenue
Box 5080
Des Plains, Illinois 60018 USA
   Publishes Ceramic Industry magazine
Indian Ceramic Society
Central Glass and Ceramic Research Institute
Calcultta 700032
Indonesia Ceramic Research Institute
J1. Jend. Achmad Yani 392
Bandung, West Java
Bonnot Company
Chambers Brothers Division
805 Lake Street
Kent, Ohio 44240 USA
British Ceramic Plant and Machinery
  Manufacturer's Association
Box 87
Weybridge, Surrey, KT13 9JS, UK
Denver Equipment Division
Joy Manufacturing Company
Box 340
Colorado Springs, Colorado 80903 USA
Globe Trading Company (used equipment)
1801 Atwater Ave.
Detroit, Michigan 48207 USA
International Clay Machinery
  of Delaware, Inc.
Box 211
Wellsville, Ohio 43968 USA
Mohr Machinery Company, Inc. (used equipment)
Box 1148
Dearborn, Michigan 48121 USA
Netzsch, Inc.
Sub. Gebrueder Netzsch
119 Pickering Way
Exton, Pennsylvania 19341-1393 USA
Via Statale Selica
40026 Imola, ITALY
Takasago Industry Company, Ltd.
Toki-city, Gifu-pref, JAPAN 09-54
A. J. Wahl, Inc.
8961 Central Avenue
Brockton, New York 14716 USA
Paul O. Abbe, Inc.
400 Center Avenue
Little Falls, New Jersey 07424 USA
American Clay Machinery Corporation
1716 Dillion Place, NE
Canton, Ohio 44705 USA
Clearfield Machine Company
Box 992A
Clearfield, Pennsylvania 16830 USA
National Engineering Company
Simpson Mix-Muller Division
20 N. Wacker Drive, Suite 2060
Chicago, Illinois 60606 USA
Malkin, Ltd.
Campbell Road
Stoke-on-Trent, ST4 4ES, UK
Maxon Corporation
Box 2068
Muncie, Indiana 47302 USA
Miller Equipment Company
Box 1856
Salisbury, North Carolina 28144 USA
Alpine American Corporation
Box 389
Natick, Massachusetts 01760 USA
Edward & Jones, Inc.
Box 128, 563 Eagle Rock Avenue
Roseland, New Jersey 07068 USA
FRH Extruding Machines
Plymouth Locomotive works
Bell and High Streets
Plymouth, Ohio 44865 USA
Haendle, Karl & Soehne
Postfach 1251
D-713 Muehlacker, WEST GERMANY
Alpine, A.D., Inc.
3051 Fujita Street
Torrance, California 90505 USA
Bickley Furnaces, Inc.
Box 6069
Philadelphia, Pennsylvania 19114 USA
Harrop Industries, Inc.
3470 E. Fifth Avenue
Columbus, Ohio 43219 USA
Heimsoth Keramische Ofen
Schuetzenallee 41
3200 Hildesheim, WEST GERMANY
Anhydro, Inc.
165 John L. Dietsch Square
Attleboro Falls, Massachusetts 02763 USA
Abex Corporation
Dension Division
1220 Dublin Road
Columbus, Ohio 43216 USA
AC Compacting Presses, Inc.
Box 1766
New Brunswick, New Jersey 08902 USA
Cincinnati, Inc.
Box 11111
Cincinnati, Ohio 45211 USA
J.C. Steele & Sons, Inc.
Box 951
710 S. Mulberry Street
Statesville, North Carolina 28677 USA
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     Press, 1976.
Ceramics Monthly.  1609 North West Boulevard, Columbus, Ohio
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Conrad, J. W.  Ceramic Formulas:  The Complete Compendium (A Guide
     to Clay, Glazes, Enamel, Glass, and Their Colors).  New York,
     New York:   MacMillan Publishing Co., 1975.
Cooper, E.  The Potter's Book of Glaze Recipes.  New York, New
     York:   Charles Scribner's Sons, 1980.
Green, David.  Pottery Glazes.  New York:   Watson Guptill Publishing,
Nelson, Glenn.  Ceramics--A Potter's Handbook.  New York:  Holt,
     Reinhart &  Winston, 1984.
Norton, F. H.  Elements of Ceramics.  Redding, Massachusetts:  Addison-Wesley
     Publishing Co., 1974.
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Rhodes, D.  Clay and Glazes for the Potter.  Radnor, Pennsylvania:
     Chilton Book Co., 1957.
_____.  Kilns--Design, Construction and Operation.   Philadelphia,
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_____.  Stoneware and Porcelain:  The Art of High Fired Pottery.
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