More Resources

Note: This section contains five pages. Return to Page 1 or Page 2, Page 3, or Page 5

Books

Hands on Clay: An Introduction to Ceramics by Charlotte Speight and John Toki

The Potter's Studio Clay and Glaze Handbook: An Essential Guide to Choosing, Working, and Designing with Clay and Glaze in the Ceramic Studio by Jeff Zamek

Clay and Glazes for The Potter by Daniel Rhodes

Primitive Pottery by Hal Riegger

Alternative Kilns & Firing Techniques: Raku, Saggar, Pit, and Barrel by James C. Watkins

Hand Building Techniques by Joaquim Chavarria

The Complete Potter's Companion by Tony Birks

Handbuilt Pottery Techniques Revealed: The secrets of handbuilding shown in unique cutaway photography by Jacqui Atkin

Websites

Wedging Clay Tutorial with Photos
Goshen College

Where does clay come from? by Jenny Gulch

Clay's important features by F.H. Norton

Photo of clay rock deposit

Principal Clay Types Used in Ceramics
Hammill & Gillsepie

Clay and Ceramics Info
Clay Times

Clay minerals

Raw materials dictionary
Sheffield Pottery

Watch how feldspar weathers into clay particles video

Digging up and creating pottery with your own clay
eHow
video

How to Make a Pinch Pot video

How to make a casting slip
Laguna Clay

Terra Cotta Slip Casting Recipes
DigitalFire.com

Things to remember about Coil Pots

Clay coiling tutorial

How to use an extruder
GlynnisLessing.com

Create Your Own Homemade Foot-Powered Extruder
Ceramic Arts Daily

Introduction to pottery making

A Photographic Tour of Firing Pottery (using the open fire method)
NativeTech.org

The art of ceramics
NALIS

Learning to Throw Pottery
Marvin Bartel

How to make pottery

Cat Litter, Antacid and other non-traditional glaze materials
Ceramics Today

Make Pottery Glaze with Simple Household Chemicals
ehow.com

Kiln Firing Chart (PDF)

Cone Temperature Chart
BigCeramicsStore.com

Pyrometric Cone Charts

Pottery and Ceramics

Continued from Page 3

Step Four: Throwing Pottery

Long before Jesus of Nazareth plied his trade as a carpenter, potters had already moved on from hand building techniques to bigger and better things. For some, the ability to turn out large quantities of pots in a short amount of time topped the priority list, as interstate commerce (so to speak) had become commonplace. Around the Mediterranean Sea, for example, ancient shipwrecks have coughed up vast caches of amphorae. These pots were a staple of marine transport, notably between the teeming city of Carthage (in Tunisia) and southern Europe. Thus, the pottery wheel proved an indispensible tool in creating a standard size and shape of pot that could be handled efficiently and securely where long travel distances were involved.

Ancient amphorae recovered from a sunken ship dated to a couple thousand years ago is the subject of this display in the archaeological museum at Istanbul's Gulhane Park.

While dating this time-saving workhorse to a particular time and place is impossible, by the dawn of the Bronze Age in 3000 BC, rudimentary potter's wheels were already in use. These consisted of a round stone or ceramic plate pushed by hand around a simply rigged point of rotation. In fact, throughout Asia, various forms of the device are still in operation today. Nowadays, the wheels are most often made from concrete, a material that's ideal for generating a lot of natural forward momentum.

In Japan, the legendary potter Shoji Hamada (1894-1978) followed a tradition of cermacists before him when he placed a stick onto his wheel and wound it four times to start its motion. This stick propulsion derived much more energy than simply giving the wheel a push from its side. Naturally, as the clay gets centered and worked, the pressure exerted by the potter creates an opposing force (or friction) on the spinning wheel, slowing it down. After a minute or two, the potter wields his stick and gives it another whirl. Hamada produced hundreds, if not thousands, of large decorative, museum-quality pots in this manner.

Through time, pottery wheels evolved to become a lot more sophisticated than that. For most of us, its most important innovation may have been the introduction of a shaft that lifted the wheelhead high off the ground. This made the task of "throwing" a lot easier on the potter's back, since he or she no longer needed to sit on the ground like Buddha.

An apprentice potter in Avanos, Turkey shaping a pot from red clay.

In the Muslim world, an amphora-type pot was devised (or repurposed) to hold a small throwing wheel aloft. Down at foot level, a flywheel attached to the amphora allowed the potter to keep his wheelhead in constant motion. By pushing the flywheel into motion with the bottom of the foot, the potter could keep his hands on the pot under construction. Thus, the flywheel had to be elevated a few inches off the ground in order to spin.

In Europe, the kick wheel, as this more technologically advance machine became known, would develop further, encompassing a cube-shaped wooden or metal frame that served to balance the flywheel-shaft-wheelhead mechanism rotating at its center. Unlike the traditional wheels in Central Asia, this contruction could support a much larger wheelhead, typically 14 inches in diameter. Later, a treadle was substituted for the flywheel by some potters, an innovation borrowed from the textile spinning wheel and sewing machine. With this mechanism, the potter gets more power out of his foot by pumping a lever. A treadle also makes it easier to work at variable speeds.

At left, an llustration of a treadle-propelled pottery wheel. At right, a traditional kick wheel from Erfurt, Germany. Source: Left/Pearson Scott Foresman, Right/Wikipedia.

With the advent of electrical power, motors entered the world of pottery making. Initially incorporated as a simple attachment to drive the flywheel, manufacturers eventually designed an automated machine that could be controlled with a foot pedal. With a frame of cast aluminum and/or powder-coated steel, these pottery wheels require little time to learn. Tucked away and largely unseen are the motor (typically 1/4 to 2 HP), a belt revolving around two pulleys attached to shafts (usually a Poly-V belt drive), and a controller that houses the electrical circuit board. Unfortunately, even the low-budget models cost over $750. Kick wheels are still available, but the freight costs can be prohibitive. An accessory motor to drive the flywheel can also be purchased.)

This homemade version of an automated pottery wheel was built by the author and includes a 1/2 HP Leeson 90V motor, along with a PWM controller, Lockerbie 14" wheelhead, Shimpo splashpan and a V-belt drive. However, the goal of saving money over buying a brand name machine was not realized. The individual components and hardware cost over $700!

Regardless of whether you have a motorized or manually propelled pottery wheel to work with, the basic skills needed to form pots is the same. Here's a quick rundown of the primary ones, along with some of the better throwing instruction videos posted on YouTube:

Choose a clay body that has lots of plasticity and is low in refractory materials. For high-fire ceramics, a grayish stoneware clay used in colleges is B-mix with a little grog. Although it's refractory, the grog keeps the thin walls of a cylinder shift from collapsing on the wheel. Grog also helps to minimize the inevitable shrinkage caused by ball clays, which are present in most throwing mixes.


Wedging clay disperses moisture evenly around the clay while removing lumps or air pockets. It's also needed to combine different clays and raw materials. Photo: Goshen.edu

Knead or wedge the clay before throwing it, and make sure it's not too hard. You want the clay has a uniform look and can be easily shaped by your hands on the wheel, rather than a huge battle. Of course, a professional potter can throw a shovelful of clay dug out of a river bed and make it work, but a beginner should spend the extra time getting the clay body limber and ready to rumble. Here's a tutorial from Goshen College that shows you how it's done.

Center your ball or clay lump on the wheel using a method called coning. When you first start throwing an object, you should have a bucket of water at the ready, since you'll dip your hands in it repeatedly throughout the process. The water prevents friction and allows you to rinse off small clumps of clay that build up on your hands. Coning, meanwhile, serves the dual purpose of distributing new water throughout the clay (inside and out), softening it up for shaping. In fact, coning makes short work of getting the clay centered on the wheelhead, even for the most inept student of the trade. You'll need to turn up the speed on the wheel to derive the force (or torque) necessary to move the clay around.

Throwing Tip: Always keep both elbows near your body so your hands will apply pressure evenly on both sides and at the same angle of trajectory. If you're a small person, you may need to place a couple of footrests on the floor to give you more leverage when centering.

Pull out the hollow opening in the middle of the clay, first by sticking a thumb (or both thumbs) into the top and drilling down to the bottom. You should stop about a quarter inch from the metal of the wheel, which is hard to gauge at first. Students are taught to stop the wheel and stick their needle tool into the clay to see how thick a bottom they have. Once you get the depth right, you can perform the pull. This is usually done with three fingers of one or both hands and creates a rough cylinder shape.

Next comes the tricky part, which requires you to perform a series of lifts to raise the clay to a certain height or wall thickness. Naturally, if you're making a bowl, this step is a lot different than if you're creating a vase, amphora or decorative pot. But the general idea is to compact the wall with a finger or thumb (or multiple fingers) on each side and slowly lift vertically in a straight line. For this operation, the wheel should spin relatively slow. As a rule, four lifts is generally what it takes to get the cylinder formed.

During the course of throwing, you may find that the object falls out of center on the wheel, or its opening becomes too wide in one or more spots. Here, you can use a technique called collaring to nudge the object back to center and/or reduce its diameter. To collar, cup your thumb and middle finger on either hand and raising them up on either side of the clay, starting from the bottom and lifting upward. The slight pressure exerted causes the clay to contract inward and regain a symmetrical centered shape. Collaring also lifts the clay wall higher, but not as effectivey as the lifts that usepressure on either side.

-

Potter Antoinette Badenhorst demonstrates collaring (left) and how to form the lip of a pot on a wheel. An illustrated tutorial is provided on her website.

If your lump of clay is still hanging together on the wheel after all this activity, congratulations, you're ready to start shaping it into its final curvature or form. For this job, the potter uses a rib - wooden, rubber or metal. While pressing the edge of the rib against the inner or outer side of the wall, a hand (or sponge) is placed on the opposite side to keep the wall from buckling when pressure is applied. As far as the artistry of throwing goes, this is where the rubber meets the road. The taks can also be performed earlier in the process if the wall becomes uneven around the pot between each lift. Rather than directing the wall outward or inward, however, the rib is typically held perpendicular to the wheel head.

The next step is to shape the lip of the pot, either with your fingers or a tool. The objective here is a smooth, curving lip like the ones you see on all pottery. It's common to leave the lip a little thick until the very end of throwing, when the potter can concentrate on the diameter and form through collaring or the use of a tool.

Once the pot is complete, you'll have to remove it from the wheel without damaging its shape. Since the clay is extremely wet at this point, this is not an easy task to accomplish. For one thing, it's stuck to the bottom of the wheelhead. You must first cut a line around the base of the pot with the long wood carving tool, then pull your clay-cutting wire through the indentation created, cutting as close to the metal as possible. Here it's essential to hold the two ends of the wire taut, as if it were a saw. Aftterward, you gently grab the pot on either side and nudge it off the wheelhead. Because this step can be difficult, many students (and even long-time professionals) throw their projects on a wooden or plastic bat. This is a plate that screws onto the wheelhead with two bat pins inserted through bored holes in the metal 10" apart. Once the pot is thrown, you can remove the screws and simply set the bat aside to allow the clay to dry a bit.

Once the finished pot becomes leather hard (but not too hard), the last step of throwing is to carve the clay down to its final shape. This includes making sure any lid or other attachment fits the pot properly. Besides carving tools, the potter uses a metal rib to flatten and smooth out the walls on the outside, which makes them easier to glaze after firing. Alternatively, lines, texture and other decorative features can be carved onto the outside walls.

The secret to throwing is not really a secret . As you can see, there are several skills involved - wedging, centering, pulling, lifting, carving, etc. Practice, patience, preserverance and mentor (if you can find one) will pave the way to proficiency. While hand building may be easier to master initially, once you learn to throw, it will probably require an act of Congress to drag you off your wheel from there on out.

And in case you're wondering, the term "throwing" derives from an old English word "thrawan", which means to twist or turn. For more on the name, read the explanation provided by Lakeside Pottery.

- - - - - - - - - - - - - - - - - - - - - - - - - -

Continued on Page 4... (Firing Clay in a Kiln)

- - - - - - - - - - - - - - - - - - - - - - - - - -

Return to: Mega-Disaster Planner

- - - - - - - - - - - - - - - - - - - - - - - - - -

Copyright 2009-2014 The City Edition

Home | Survival |Food | Medicine | Evacuation | Disaster Monitoring | 2012
TheCityEdition.com

Optional Index:

Pottery & Ceramics
Carpentry
Chemistry
Leather Work
Basic Mechanics
Raw Materials
Blacksmithing
Housing Construction
Sewing & Cloth
Flintknapping
Mineral Prospecting