CHAPTER ONE
THE BASICS
WHETHER YOU’RE NEW to the potter’s wheel or you’ve been throwing for some time, this chapter will likely have some new ideas that can enhance your studio habits—or even your life! In addition to tools and materials and general studio setup, in this chapter I’ll cover proper studio safety, body mechanics, and techniques on the wheel. I encourage you to think about these areas as the legs of a three-pointed stool. Taking away any of these will make your studio practice unstable and much harder to balance.
Over the years I have worked in a variety of production potteries both large and small. They have their individual quirks, but there are a few common denominators that they share. One unexpected trait that was common in the more successful studios was studio cleanliness. The studios that were the most productive also incorporated a cleaning routine into their workweek. It taught me that cleanliness is not only a health issue but also an efficiency issue. The more deliberate a studio is about planning their studio space, the more deliberate they ended up being with the aesthetic and business decisions they made in their work.
In the middle of the chapter, I delve into effective body mechanics and proper posture. This information aims to help you understand how using the wheel affects your body. As potters, we spend hours sitting at the wheel often to the peril of our spinal and neuromuscular health. I’ve included instruction on proper body alignment as well as exercises that might help correct problems you are already experiencing. Back pain is not a prerequisite for being a good potter, so I encourage you to come back to this section every six months or so to fine-tune the way you interact with the wheel.
Another part of the chapter you should consider reading even if you’re already familiar with wheel-throwing is the section on choosing a clay body for throwing. Even if you are an experienced thrower, I’d like you to consider how the clay you use affects your sense of touch and aesthetic. For example, I threw porcelain for many years, and its finicky nature still informs the way I manipulate terra cotta in my current body of work.
STUDIO SAFETY
When thinking about safety in the studio, remember the saying “pay now or pay later.” There is a cause and effect relationship between our present actions and our future selves. Cutting safety measures might seem like a time saver when you are rushing around in your studio, but those actions have a long-term cost on your body and your future comfort. Your body is your greatest tool, so protect it and enjoy a happy and healthy studio life for years to come. The goal of this section is to build a foundation of healthy ideas and methods that will support your future quality of life in and out of the studio.
Clay trimmings might not be the first thing you think about when it comes to silica dust, but dry clay scraps of any sort will release dust into the air if disturbed.
MITIGATING SILICA DUST
Your first studio safety concern is mitigating silica dust and other lung irritants. As a core component of both clay bodies and glaze, silica is present in all stages of the ceramic process. While it is harmless to the touch, it can be progressively harmful once it enters your lungs. Prolonged exposure to silica dust is linked to an emphysema-like condition known as silicosis.
When working in your studio, you might create a small cloud of dust when moving clay bags or mixing glazes. Your instinct tells you to back away from the cloud until it dissipates. While this is generally a good idea, it also points to a misconception about dust. The most harmful particles of silica and other lung irritants are not the ones you see but the ones that are invisible to the naked eye. Because of their microscopic nature, these particles can easily float in the air of your studio for a few hours or even days. To maintain a safe, dust-free studio, it is important to establish best practices for mitigating dust.
The cardinal rule of clay safety, no matter what studio you’re in, is to avoid sweeping or moving dry clay particles. The best way to move clay particles is to hydrate them or contain them in a closed, airtight container. Mopping is both more efficient and safer than sweeping because the water binds the clay particles, keeping them from becoming airborne. If you need to wipe down the surfaces of your wheel or studio counters, do so with a wet sponge instead of a dry rag. The less silica you allow into the air, the less potential it has for entering your lungs.
One common practice that will lift dust into the air is the collection of dry trim scraps. It is easy to mistake these chunks of clay as large enough to not be dangerous. The unfortunate reality is that every time you touch trim scraps, you are breaking off smaller pieces, which can then become airborne. The best practice is to collect scraps when they are leather hard and are less likely to break down into airborne particles. As the clay particles dry, they become a hazard, so if you must collect dry scraps, push them into a bucket partially filled with water using a wet cloth.
A particulate respirator can be used to safeguard your lungs during any activity that requires contact with dry clay particles. This includes studio cleaning, glaze preparation, and clay mixing. Cheap disposable respirators can be purchased from your hardware store, but I suggest you invest in an industrial respirator with replaceable cartridges. For maximum safety, buy an N95 respirator, which is available from hardware stores or your local clay supplier.
If you are embarking on a professional career in clay, I recommend you purchase an air filtration system that is rated for silica. The upfront cost of this purchase might seem steep, but you will save more money on health care costs in the long run. This brings up a general principle that I apply to studio safety: invest time and money into your health now to save money on lost work time and medical costs in the future. Your body is your greatest tool, so maintain it like you would a luxury car. Five minutes of daily maintenance can be easily built into your studio life, creating health rewards that will last a lifetime.
TOXIC MATERIALS
Another studio safety concern is the handling of toxic materials. I have already discussed methods for mitigating airborne particles, so I now want to focus on soluble materials. Because this class of contaminants will dissolve in water, they can be absorbed through your skin. The majority of soluble toxic materials are found in glaze labs where they are used as colorants or fluxes. As the focus of this book is wheel throwing, I will not spend a lot of time on this subject, but I want to highlight a few particularly toxic materials. For a complete explanation of toxicity with glaze materials, I recommend you read John Britt’s The Complete Guide to Mid-Range Glazes.
There are some ceramic materials that you must be aware of at all times if they are in your studio. Think about them like hyperactive teenagers that might bring you happiness but can easily get out of control if you are not paying attention. Materials in this category include chrome, manganese, copper, vanadium, and other soluble heavy-metal colorants. These materials should be kept in a hard plastic container to reduce spillage and unwanted contamination. The only material in this category that you are likely to come into contact with on the wheel is manganese. Many black clays have a percentage of manganese to help them achieve their rich colors. If you choose to use these clays, I recommend wearing plastic gloves when you are forming the clay. I also recommend you take special care when firing to insure no fumes from the kiln enter your studio air supply. A kiln-venting system that exhausts fumes outside your studio is recommended if you plan to use these on a regular basis.
There are other ceramic materials that I recommend you avoid all together unless absolutely necessary—lead, uranium, barium, cadmium, and coloring sulfates are in this category. While these do vary in toxicity, the main reason I recommend avoiding them is that ceramic technology has provided us acceptable substitutes. The toxicity risk is not worth the reward. For up-to-date substitutions for toxic materials, you can visit www.digitalfire.com.
POSTURE
The last safety concern in this section is improper body alignment, which can lead to repetitive motion injuries. This category is often overlooked and underestimated in its impact on an artist’s career, yet back health is an ongoing concern for many potters. Years ago, I actually developed chronic back pain from poor posture and harmful studio practices. After many trips to chiropractors, massage therapists, and other medical professionals, I decided to change the way I interacted with the wheel.
My first change was to elevate my wheel upright on cinder blocks so that my spine was straight during the act of throwing. To determine the ideal height of the wheel for you, sit comfortably in a chair that you would use for throwing. The sitting surface of the chair should be high enough that your knees are parallel to, or slightly below, your hips. Sitting with a straight back, bend your arms at a 90-degree angle and let them rest by your sides. The surface of your wheel should be about one inch below your forearms. This wheel height will allow you to use your hands in front of your torso without curving your back. If you must bend forward, bend from the hips and not the curve of your back. I have also seen potters throw standing up with their back against a wall to encourage a more upright posture.
As you sit at the wheel you’ll continually focus your attention and body posture forward. Over time, the pectoral and abdominal muscles tighten, causing you to lean slightly forward even if you are standing straight. This can be the start of many lower back issues. To correct the misalignment of your frame, you need to consciously work the muscles that reverse this process. Stretching abdominals in conjunction with strengthening lower and upper back muscles will bring your torso alignment back to a natural position. Below, you will see exercises that are geared toward strengthening the back while encouraging upright posture. I encourage you to participate in a weekly yoga or Pilates class to develop the core strength needed for a successful studio practice.
Note: See the interview shown here for tips on maintaining back health, including three exercises.
Another area that can be problematic is the neck and trapezius muscles. In the process of wheel work, you often spend a lot of time looking down. This can cause neck and upper back strain, making for a painful work day. To keep this problem to a minimum, I counter the time spent looking down at the wheel with other tasks that keep my head up. For my decoration process, I sit at a table with my elbows resting on the tabletop. When painting or carving, I raise the piece on an elevated banding wheel so that the center of the piece rests at the middle of my torso. This allows me to focus on the piece without looking down. Another general rule I follow is to stand up for about three minutes for every twenty-minute interval. I try to do this no matter what I am doing. By returning to a standing position, I allow my body to realign before going back to the task at hand.
Along with back health, you should also consider the role your hands play in the forming process. The hardness of clay you use will affect the amount of force needed to shape a form. During an early production pottery job, I was taught to use stiff clay as a short cut to throwing taller. This can be helpful at times, but it required that I use more force in my wrist and arms. After only a few years, I started to develop carpal tunnel syndrome. Thankfully chiropractic care realigned the bones in my wrist, but it was a wake-up call for my wrist health. I now use the softest clay possible to throw. With proper wheel control and clay plasticity, you will be able to create any form you wish with minimal body stress. At times I use a heat gun or blowtorch to selectively dry a portion of the pot to achieve the curves necessary on a large form. I prefer this pain-free method of selective drying as opposed to using stiff clay.
To develop a successful ceramic practice, you must cultivate a flow of body movements suited to the creation of the objects you are interested in making. Creating a beautiful pot is only partially a success if you’re damaging your body in the process. Mastering the potter’s wheel does not have to come at the expense of your body.
EXERCISES
Some of you might already have back pain, which could be affecting your productivity and enjoyment of making pottery. I want to reassure you that you can learn a pain-free way to make pottery. Pain is not a requirement for making good pots. Do your best to eliminate the belief that pain is a necessary part of your life as a practicing potter. It is an unnecessary byproduct of bad technique that can be removed with a little effort and mindfulness during your throwing practice.
Before we get into the exercises, I want to talk about the difference between sharp and dull pain. During these exercises, you might feel a dull pain that feels like someone is pulling on your muscles. This is a normal sensation as your movement elongates the muscles and tendons in your body. Sharp pain, however, is not normal. If you ever have the sensation that someone is poking you with a sharp object, you should immediately back off. Adjust your range of movement to eliminate sharp pain but continue to do the exercises.
This set of movements can be done as a warm-up before throwing or during your lunch break. One rule that I keep in mind is to incorporate one set of exercises into my daily schedule and then add an additional set any time the idea pops into my head. If I think, “I need to exercise,” I often stop right then and do a set. In my experience, putting it off until later usually means it doesn’t get done.
If you haven’t already read the feature on spinal alignment by Dr. Ron Schmidt shown here, please do so. He gives a simple explanation about how spinal misalignment occurs and how that turns into pain. He also offers suggestions for exercises that you might incorporate into your studio day. The Foundation exercise regime developed by Dr. Eric Goodman and Sue Hitzmann’s book The MELT Method both offer more information on developing back strength and flexibility.
In the exercises that follow, I will elaborate on a set of stretches that can help you to adjust your resting spinal alignment by opening your chest cavity and elongating your abdominal muscles. Tightening of these two muscle groups comes from the constant forward pressure that is exerted when working at the wheel. To correct problems you might already be having and avoid problems that might arise in the future, focus on loosening the front of your body while strengthening the muscles in the back. With only fifteen minutes a day devoted to these stretches, you will gain years of pain-free pottery making.
By raising the wheel up on blocks, you will be able to sit upright with your spine resting in a neutral position. This protects the discs in your back, making sure your pottery career will be as pain-free as possible.
Angel Wing
This exercise is good for opening the chest cavity while engaging shoulder muscles.
Stand with your back against a wall, with your arms raised to shoulder height and your elbows bent at a 90-degree angle. A Relax the shoulders so that they are not scrunched up tight against your ears. Raise your hands above your head while keeping your elbows bent, like you are making an angel in the snow. B During the movement, keep your fingers lightly pressed back against the wall as you move your hands upward. Don’t worry if you can’t touch your hands together at the top. You should feel a stretch throughout your shoulders, arms, and chest as your hands move above your head. Perform ten repetitions, counting to five on the way up and on the way down.
Open the Cage
This exercise is also good for opening the chest cavity while engaging shoulder muscles.
Stand perpendicular to a wall, reaching your hand out to touch the wall. Your elbow should be bent at a 90-degree angle and your palm should face the wall. C Taking this position, you might already feel a stretch in the front of your chest. If you feel tightness in the shoulder, stay in this position, taking moderately deep breaths until the muscles loosen.
Step one leg forward approximately 6 inches while keeping your arm in the same perpendicular position to the wall. D Step the other foot forward so that your arm is behind you resting against the wall. E If the stretch in your chest is not deep enough, move your feet forward another few inches. Try not to twist your torso as you perform the stretch, as keeping the torso straight will increase the stretch. Hold the position for twenty moderately deep breaths, counting each inhale and exhale as one repetition. Switch sides and repeat the stretch on your other arm.
Upward Facing Dog: Studio Variation
This exercise is good for stretching the abdominal muscles while strengthening the lower back.
Of the three exercises, this variation on the yoga pose Upward Facing Dog is the most challenging and can be too much for people who already have back problems. I encourage you to move slowly into the posture breathing through the dull pain of stretching but backing away from any sharp pain that is brought on by the movement. One of the best qualities of this exercise is that it engages the full spectrum of muscles in the lower torso. It is an all-in-one strengthening and stretching exercise that will help relieve tension in the lower back.
First, stand in front of a sturdy table whose surface is hip height. Place both hands palm down and take one small step backward. F Pull your shoulder blades down away from your ears before letting them rest in a softly engaged position. Place feet parallel to each other, forming a straight line from your heels to your head, establishing an engaged neutral spine. G At this point you might feel a stretch in your calf muscles and abdominals. If needed, stay in this position for a few deep breaths until your muscles relax.
Keeping your feet planted and your eyes forward, engage your gluteal muscles, moving your hips toward the table. The movement will create a back-bending stretch. H Keep in mind that you have the option of bracing your hips on the table for support. Consider moving your feet closer, or farther away, from the table to adjust the depth of the stretch. For those who do not have neck problems and want a deeper stretch, tilt your head up looking backward. Once in the posture, hold for three breaths before returning to a neutral spine. Take the posture again, holding for five breaths before returning to a neutral spine. Take the posture a final time, holding for seven breaths before returning to a neutral spine.
Downward Facing Dog: Studio Variation
This exercise (not pictured) is good for releasing tension in the lower back after performing the Upward Facing Dog stretch.
After performing your Upward Facing Dog stretches, you might feel tension in your lower back. To relax those muscles, move into a Downward Facing Dog posture. First, stand approximately 18 inches away from the table. Imagine you have a rod running down the back of your head through your spine to your hips. Bending at the hips with a straight spine, place your hands palm down on the table. Keep your head up throughout this stretch, as that will help keep your back from rounding. Push backward with your hips to feel a stretch in your hamstring muscles and lower back. Hold for three breaths before returning to an upright position. Repeat for two more rounds, increasing your breath to five and seven breaths while holding the stretch.
As you become more comfortable with the postures, consider moving back and forth between Upward Facing Dog and Downward Facing Dog. Be mindful of making a slow transition between postures, taking a momentary pause when you reach a neutral spine.
Biomechanics with Ron Schmidt
Dr. Ron Schmidt graduated from Palmer College of Chiropractic and has been in practice for over twenty years. Dr. Schmidt was deemed out of a group of 2,000 chiropractors spanning from Utah to Hawaii to be the most valuable in regards to providing the highest standard of care to the patients while giving back to the respective community. Dr. Schmidt has been practicing at Action Chiropractic in Santa Cruz, California, since 2005 and is determined to maintain the application of the most recent researched techniques to provide the best and most complete care for the patient.
When discussing the biomechanics of the body, one must understand the key components that affect those biomechanics. The constant force of gravity is either working for you or against you. Gravity is working for you when you maintain a neutral spine position/posture. Neutral spine is a plumb-line from a side view in which the ear falls over the shoulder, the shoulder falls over the hips, and the hips fall over the bony prominence of the ankles. In this position, most of gravity’s force is applied over the skeletal system which is held together by a network of connective tissue, which has very little to do with the muscular system. A good example is if you were to rest your elbow on a table with your forearm at 90 degrees while holding a bowling ball. We mistakenly think the muscular system holds us up, when in fact it is the skeletal system combined with connective tissue. The skeletal system is wrapped by a continuous three-dimensional network of connective tissue called fascia. The fascia surrounds and supports all aspects of the body, including the muscles, bones, joints, nerves, and organs. It is as though someone took one piece of plastic wrap and wrapped it around every muscle, organ, bone, joint, and nerve. The fascia morphs into different positions as we move and is loaded with sensory nerves called mechanoreceptors. The mechanoreceptors feed information back to the brain so the brain knows what is happening positionally with the body. The fascia is also loaded with pain receptors.
When we are out of neutral spine posture, gravity is placing abnormal loads on the structures not properly supported. For instance, holding a bowling ball at an angle places abnormal loads on the elbow joint, which requires the use of the arm’s muscles for support (comparable to a spine in poor posture affecting the associated joints and muscles). Over time, those muscles fatigue and create inflammation, which increases fibrosing-adhesion (which is like glue) in and around the muscle, the fascia, and the elbow joint in this example. If the poor positioning is ongoing, the joint degenerates (osteoarthritis), the muscles become functionally weak and fatigue easily, while the fascia dehydrates like a dried-up sponge. This triggers the pain receptors in the fascia, muscles, and joints: you have now developed a chronic pain condition. It is these repetitive poor postures or activities that cause trouble, and this is why chronic pain is an epidemic in our society.
The next questions are “How does one prevent this condition?” and “What can one do to try to reverse the damage?” First, we must always try to maintain a neutral posture. If bending forward, it’s best to hinge at the waist instead of rounding the back. In pottery that can be difficult, if not impossible. The key is to take regular breaks approximately every twenty to thirty minutes, and do an exercise that puts you in the opposite posture. I always recommend the Foundation Exercises by Dr. Eric Goodman to my patients. This postured exercise works all of the extensor back muscles at one time, so you get a lot of bang for your buck. To do the exercise, stand with your feet shoulder width apart and your weight on your heels. Start squatting slightly while maintaining the weight on your heels, then roll your shoulders back and down with your arms extended and pulling backwards. At the same time, glide your chin back like you are trying to make a double chin. You should resemble a long-jump skier. Hold this posture for twenty seconds, rest for twenty seconds, and repeat, each time squatting a little lower. This exercise works on strength while increasing the endurance of your back muscles. It also opens up your chest cavity, which allows for a greater volume of air into your lungs.
In addition to the Foundation Exercises, it is also important to address areas of fibrosing and dehydration in the connective tissues. To work on this, you will need a foam roller and a tennis ball. Using these simple tools softens the adhesions and hydrates the tissue, making it like a wet sponge that is moist and pliable. This will downgrade the pain receptors while improving the neural sensory input to the brain. The end result will be better coordination of movement and balance with less chance of joint or muscle injury. You can use a foam roller for legs and back and you can use a tennis ball for areas in and around your shoulder blades (also known as the scapula). As a potter or sculptor, it is also essential that you work the muscles and fascia of the forearms and hands. Small rubber balls are good for the palms of your hand, and you can use the tennis ball on your forearms. A complete ten-minute treatment protocol, done at a frequency of three times a week, was developed by Sue Hitzmann in her book titled The MELT Method, which I highly recommend. It is important to stay hydrated, especially after using a foam roller. Hydrating your connective tissues will reduce areas of stuck stress not only in your fascia but also in your joints. I also highly recommend utilizing the expertise of a chiropractor to reduce areas of stuck stress that you already have in your skeletal system.
Following this protocol as a part of your well-ness plan will reduce the negative effects of abnormal mechanical loads to your neuromuscular-skeletal system. As a result, your body will experience less pain, better movement, and less neurological stress, resulting in better sleep and more freedom for creativity.
TOOLS AND MATERIALS
Since you can’t throw on a potter’s wheel without the wheel, let’s start this section with the wheel itself. Fortunately for potters, there are a variety of companies making high-quality wheels. When choosing a wheel, I recommend you consider three main characteristics: horsepower, transmission type, and pedal sensitivity. I will discuss each of these considerations in detail. Note that while your studio may be equipped with a kick wheel or you may be interested in purchasing a kick wheel, you obviously won’t need to evaluate the motor as kick wheels are most often free of a motor and other electronics.
WHEELS
Most companies offer a range of horsepower starting with 0.25 horsepower and going up to 1.5 horsepower. With increased horsepower, you will be able to throw a larger amount of clay at a time. Beginner and novice wheel workers won’t notice much of a difference between models, but advanced potters throwing more than 50 pounds at a time will need the extra horsepower to not experience drag in the motor. Even if you are starting out, I recommend purchasing a wheel with 1/2 horsepower or more.
Preference between transmission types is based on individual needs and often past history with one style or the other. I know potters that swear by a certain type of transmission, but after using national brands in many different countries, I believe most preferences are flexible. Belt drives, ring/cone drives, and direct drives are all effective and have idiosyncrasies that make them more or less appreciated by working potters. For reviews on transmission types, I recommend you search the Clay Art archive or the Ceramic Arts Daily forum for more information (see Resources).
One aspect of the transmission drive you might want to research is the way the wheel head is connected to the drive. I alter many of my pots, so I prefer a ring/cone transmission that allows the wheel head to spin freely when the motor is idle. This allows me to rotate the wheel with my hand so that I can stop the pot at exactly the right spot. When using a direct drive and belt-driven transmission, depressing the foot pedal most easily moves the wheel head. You can force the wheel head to rotate on its own, but over time this will wear down the transmission. If you are in a communal studio with a variety of wheels, I recommend you try them all out to develop your own preference for the smoothness, sound, and strength of the transmission.
An independent corded foot pedal is now standard practice for wheel manufacturers. While all pedals function in a similar way, the inner workings do affect the sensitivity. When buying a wheel make sure your pedal can be adjusted both in its tension and sensitivity. These adjustments will affect the ability to start and stop the wheel head in a smooth and concise manner. If you are having trouble with your wheel head continuing to move after you stop the pedal, you might try adjusting the pedal. Read your owner’s manual for more details on making adjustments.
TOOLS
You will no doubt learn about and acquire additional tools as your wheel practice develops. If you are working in a communal studio, you will probably have access to the necessities, but before striking out on your own, I recommend you make a list of the tools you use most. Large items like a pug mill, slab roller, and industrial scale are major conveniences but might be out of your price range at the start. As you save up for these larger studio purchases, I would focus on the tools you would use while on the wheel. What follows are some of my go-to wheel, trimming, and finishing tools.
As you read through this book you will notice other unique tools, many of which can be found in kitchen supply and hardware stores. I encourage you to keep an eye out for unique textures and cutting surfaces that are used in other mediums. Many times my favorite tools are ones that I have used for years doing a non-clay task. Aside from found objects, there are a few other key tools I use for finishing pots.
Basic Wheel Tools
• Sponge A: Just about every potter uses a sponge to lubricate pots during throwing. Sponges can also be used for wheel cleanup and other water-related tasks.
• Wire cut-off tool B: This is the tool you’ll use for cutting the finished pot off the wheel or for faceting the surface of a form.
• Throwing stick C: A tool like this can be used on the inside of a tall pot when you can’t get your hand into the interior of the form.
• Pin tool D: This cutting tool is used for a variety of purposes. You can cut sections off of pots while the wheel spins, but you can also use it to do things like check how much clay you have left for the foot (see here).
• Wooden fettling knife E: The fettling knife is often used off the wheel, though it can be used to refine the foot of a pot while the form is still spinning on the wheel.
• Rib F: A large wooden bowl rib and plastic kidney rib are pictured, but there are all sorts of ribs and you will no doubt find your own favorites. Wooden ribs are often used to create a smooth, even curve on the inside of a bowl. Rubber ribs are most often used for smoothing the interior and exterior of a form. A metal rib (not pictured) can also be used for smoothing the surface of a form. Test all three rib types and compare how the density of the tool affects the surface of the clay.
• Roller tool G: This is used for drawing lines on the surface of the clay. It creates a smoother line than a pin tool, which often drags across the surface, creating burs and rough edges.
• Chamois cloth H: Use a soft cloth like this to smooth and refine the lip of a pot.
• Caliper I: Calipers are essential for measuring lids and other parts that are made separate, from the core of the pot.
Trimming Tools
• Loop tool A: These are the most common tools used for trimming away excess clay on the surface of a pot. Choose from a variety of thicknesses and widths based on your needs and preferences.
• Turning tool B: While these are also used for trimming away excess clay, turning tools remove larger chunks than the loop tool. With sufficient pressure, they can create a subtle line at the edge of the tool’s path. Many potters choose to incorporate these trimmed lines into their aesthetic.
• Surform C: Similar in shape to a cheese grater, surforms are generally used to refine large sections of a pot’s surface.
Finishing Tools
• MKM Decorating Disks A: These numbered disks are used to divide the pot into sections for decoration or altering.
• Cookie cutters B: Yes, you can use them on clay! Metal cookie cutters in particular work well for cutting shapes in clay.
• Serrated rib C: These can be used for scoring and texturing clay.
• Refinement tool D: Flexible rubber-tipped tools can be used to refine edges of handles and smooth unwanted textures.
• Craft knife E: When you need to make very precise cuts in clay, craft knives are your best bet.
• Pattern tracing tool F: Normally these are used on fabric for tracing patterns. However, on clay they can be used to make dotted lines.
• Pastry bag with nibs G: Treat your slip like icing—load up a pastry bag and use it with various nibs for decoration.
• Drying devices (not pictured): A heat gun or blowtorch will be helpful as you progress to making larger forms.
KILNS
While much of this section focuses on tools for throwing wet clay on the wheel, kilns are important tools for a pottery studio. Kilns let potters change the clay from a soft, malleable material to a rock-hard substance that can survive well beyond our lifespan. The heat necessary for this geologic reaction can come from a variety of fuel sources, including electricity, gas, and wood. When considering which kiln type to buy or build, think about potential locations for the kiln, the financial and labor cost of each firing, and any zoning or building codes that might be in effect for your studio. For more information about firing, see here.
CLAY
When we use the term “clay,” we are broadly referring a blended composite of ceramic materials. Many of these materials are produced from the decomposition of granite. Over millions of years, chemical and physical forces weather the parent igneous rock, stripping away soluble materials and leaving clay particles. The formula for clay, Al2O32SiO22H2O, hints to the fact that alumina, silica, and water are bound together as the remnants of this ancient process. Lucky for us, alumina and silica make up as much as three-quarters of the earth’s crust, resulting in thousands of clay types spread around the globe.
When choosing a clay body, think about the color, workability, and firing temperature. I prefer low-fire earthenware for its warm color and energy-efficient firing temperature.
GEOLOGY OF CLAY
Many historical pottery sites exist near veins of workable clay. While it has become increasingly rare, it is still possible to find clay that can be dug from the ground and used in the studio with minimal processing. The bulk of potters now use commercial clay bodies that are blends made from various types of mined clays, including kaolins, fire clays, and ball clays, which are then mixed with fluxes (added to lower the maturing temperature) and fillers (added for a variety of reasons surrounding the working properties of the clay). Many blended clay bodies are suitable for throwing, but their individual characteristics will make some forming techniques easier than others. For example, blended clays with high plasticity are great for altering because you can push them into a shape without cracking. The downside is that the clay particles that enhance plasticity also shrink a lot, which can create cracking problems during drying. I won’t go into a deep analysis of the attributes of specific clays, but I do want to offer you general principles that will help you find a good throwing clay. For in-depth analysis, I recommend you contact your clay supplier and talk to other potters that order from the same clay company. If you plan to dig your own clay, try to connect with a local geologist.
STATES OF CLAY
Before we go into the specifics of what makes a good clay body for throwing, I want to make sure you have a firm grasp on the stages of clay. In progression of wet to dry, you have slaked clay, plastic clay, leather-hard clay, bone-dry clay, bisqued clay, and mature (glaze-fired) clay. All clays go through these stages regardless of their finished firing temperature.
Slaked clay is largely unworkable due to its liquid nature. If a slaked clay is blunged and a deflocculant is added, it can be used as a dipping or casting slip (see here).
Plastic is the state where throwing happens. The clay can be shaped easily both on and off the wheel with minimal pressure. It will hold a form but can easily fall over if too much water or pressure is added.
Leather hard is the state where clay becomes similar to a chocolate bar. It’s strong enough to hold a curved shape but soft enough to be carved with a trimming tool.
Bone dry is the state where physical water, which rests between the matrix of clay particles that make up the form, has started to evaporate, leaving the form a lighter color. This will happen naturally if you leave your piece uncovered and exposed to room temperature conditions.
Bisque clay has been fired above 800ºF in a kiln to remove chemical water. During the firing, the clay particle sheds the water that is bound with the alumina and silica in the Al2O32SiO22H2O formula. As a result, bisque clay will never be able to return to slaked clay. Clay that has been bisque fired is porous enough to accept a glaze coat but is substantially more durable than bone-dry clay. Bisque is commonly fired from cone 08–02.
Leather-hard clay is soft enough to be manipulated but strong enough to hold curved shapes.
Mature clay has been fired to a point of reduced absorption. Vitrification, or the sealing up of clay pores, is the end of the spectrum of maturity. Most commercial clays do not reach actual vitrification and have between 2 and 4 percent absorption. For these clay bodies, some water will be able to penetrate unglazed areas of the form after firing. Most times this goes unnoticed, but in hot, wet climates high-absorption clay bodies could potentially grow mold. If this occurs, you would need to fire hotter (if your glaze will allow), reformulate your clay body to vitrify lower, or cover the foot with a terra sigillata that will seal the surface.
CLAY BODIES
When choosing a clay body, first consider the temperature range at which you’ll be firing. At various times in recent ceramic history, there were value judgments placed on clay bodies and their temperatures. It was believed that the higher you fired, the more durable the clay body, therefore the better the pot. This belief is outdated thanks to advances in clay materials that allow contemporary potters to make durable and food-safe wares at low fire (earthenware), midrange (stoneware), and high fire (stoneware and porcelain) temperatures. The choice of one temperature range over another can be practical, aesthetic, or environmental. Some potters choose low or midrange because they have access to electric kilns that are more efficient at lower temperatures, while others choose to build wood and gas kilns that easily achieve high temperatures.
The main principle to uphold is that you fire your clay, slip, and glazes to their maturation point. Underfiring your clay body might be tempting if you like glazes at a lower temperature, but this can cause a host of unwanted technical problems. With a plethora of clay recipes on the Internet as well as many manufacturers, you have the option of achieving the results you want at any temperature range. If you have access to multiple kiln styles and clay bodies, I recommend you test combinations of the two before settling on a temperature range. If you are working in a communal studio with preset clay and glazes, then focus on maximizing the materials to fit your aesthetic.
The next characteristic to consider is the color range you desire for your finished wares. Using a white or buff clay body gives you more options for vibrant and colorful glazes. Glazing on these clay bodies is like painting on a white canvas. Darker clay bodies often have iron or manganese, which will shift the glazes you use to a darker hue. Working with these clay bodies is like painting on a canvas that already has a rich base coat. One option to increase your clay colors is to apply a liquid slip on top of your clay by brushing or dipping. This will push your color scheme lighter or darker depending on your preference.
Once you have chosen your temperature and color range, it’s time to think about the workability of your clay body. An excellent throwing clay will be plastic and have tensile strength at leather-hard and bone-dry states. These qualities are based on the diverse particle sizes of the ingredients and moderate shrinkage based on overall composition. To test plasticity, you can roll a coil and wrap it around your finger. If the coil does not crack as you exert circular force, it could make a good throwing clay. Tensile strength is also affected by particle size, but you don’t have to worry about this issue because most manufactured clays have acceptable strength. If you find your pots chip during careful handling in the leather-hard or bone-dry state, then you might need to consult your clay supplier to find an acceptable alternative.
The next quality to consider is shrinkage. You can test shrinkage by rolling out a small slab that is 12cm long by 4cm wide. Mark ten 1cm increments down the middle of the slab with 1cm on each end. Allow the slab to dry to bone dry and re-measure the overall distance between the first and last mark on the slab. This is your green drying percentage, which is usually between 4 and 8 percent. This number is often not analyzed as deeply as overall shrinkage, but know that clays with heavy shrinkage before bone dry will be more sensitive to slip application.
Fire the slab to the maturation point suggested by the manufacturer. If you are working with your own recipe, test for proper maturation based on absorption (1 to 3 percent is good for a functional body). After firing to maturity, measure the distance between the marks on your slab again. Subtract your measurements from the original 10cm to calculate shrinkage. For example, if your post-fired measurement is 8.5cm, then your equation would be: 10–8.5 = 1.5. This means your shrinkage would be: 1.5 ÷ 10 = 0.15 (which is 15%). Normal ranges for shrinkage in earthenware, stoneware, and porcelain are between 8 and 20 percent, with porcelain shrinking the most. If you plan on heavily altering your pots, or subjecting them to heavy slip application, I recommend choosing a clay body with between 8 and 12 percent shrinkage. This will reduce, but not eliminate, cracking that comes from high-shrinking clays. Don’t count out clays that shrink more than 15 percent though. High-shrinkage clays include many types of porcelain, which can be exceptional clays, but you will need to regulate their drying to minimize problems.
Grog, or other coarse materials, is often added to clay bodies to help reduce shrinkage. They are non-shrinking particles, so the greater the percentage the less the body will shrink before it is bisque fired. Clays such as ball clay or kaolin are the opposite, with higher shrinkage. Having a balance of shrinking and non-shrinking particles will affect workability and determine how a clay body can be best used for forming. A great side effect of the addition of grog is that the walls of the pot stand up better during throwing. If your clay body will only be used for throwing, I suggest choosing a body that has small-particle grog. I prefer this because it is both easier on my hands and is less visible to the naked eye. You also might consider the color of the grog, which, if large enough, can speckle your clay body.
The shrinkage I have discussed so far is the contraction of the clay body during drying and firing. This process moves largely in one direction, large to small, as the pot moves through the forming, trimming, and drying process. There is also a form of expansion and contraction that happens during the firing process. This relates to the expansion/contraction that materials like silica go through during the firing. Some clay bodies are formulated to have very small expansion and contraction, so that they can be directly exposed to heat on one part of the pot. When compared to standard stoneware, these flameware bodies use high percentages of lithium as their body flux, which expands and contracts a very small amount during firing.
Ultimately, choosing a clay body comes down to balancing the look you desire with the workability of your clay. By balancing the variables of temperature, color, plasticity, grain size (grog), and shrinkage, you will be able to find clay for throwing that is both beautiful and durable.
PREPARING CLAY FOR THROWING
For thousands of years, potters dug their clay, processing it by pulverizing, slaking, and wedging the clay into a workable form. This took time, dedication, and a general knowledge of local geology. While some still choose to dig local clay, most potters have the convenience of going to a clay supplier that premixes industrially mined clays for maximum workability and fired strength. In addition to formulating easy-to-use recipes, clay suppliers also process the clay through large pug mills that de-air and filter the clay. This removes air bubbles and significantly reduces the amount of time needed to prepare clay for throwing on the wheel. Even with the prevalence of smooth, plastic clay bodies, there are still a few steps that are needed to prepare clay for throwing. In this section I will address techniques for wedging clay, as well as ways to recycle clay for repeated use.
WEDGING
Before sitting down at the wheel, you will need to wedge the amount of clay needed to make a form. The process is similar in movement to kneading bread, but with the opposite goal of removing air bubbles from the clay. I recommend dedicating a studio table, or at least a portion of the table’s surface, for the purpose of wedging. A good wedging table will be sturdy enough to withstand the pressure you will exert, be at a height that corresponds to your waistline when standing, and have a surface that the clay will not adhere to. I prefer to wedge on a wooden table that has canvas stapled onto its surface. This slightly textured surface grips the clay but does not allow it to stick. If clay does stick to the canvas, it can be easily removed with a wet sponge. Before wedging, make sure the surface you are working on is clean and dry, as you don’t want to pick up unwanted pieces of clay or other debris in the wedging process.
There are two commonly used techniques for wedging: conical and ram’s head. Both are effective, so try both to see which you prefer. Most pugged clay from manufacturers is de-aired, and less wedging will be needed as most air bubbles have been removed. While clay could theoretically be used straight out of the bag, I recommend some light wedging to make sure you have a homogenous mixture. Beyond removing air bubbles, wedging helps disperse harder or softer clay particles that might have formed from uneven drying in the plastic bag.
HOW TO WEDGE: CONICAL
1. Place your hands perpendicular to each other at a 90-degree angle on the surface of the clay. A With light pressure, rock both hands and the clay forward toward the surface of the table at a 45-degree angle. As you approach the table, your hands will open out slightly so your fingers won’t hit the table. B Rock backward at a slight angle to return to your beginning position. Notice that your hands have rotated on the clay.
2. Repeating the rocking motion, you will notice the clay begins to form a cone with a rounded point on one end and a conical swirl on the other. C The conical motion cycles the clay from the outside inward, and all bubbles will be worked out of the clay.
3. To finish the cone, rotate the wide section in a circular motion on the surface of the table. D This will round out the bottom, removing evidence of the conical. The cone is now ready for the wheel.
HOW TO WEDGE: RAM’S HEAD
1. Place your hands parallel to each other on the sides of your clay. With light pressure, rock forward at a 45-degree angle. Roll the clay back toward yourself keeping your hands and clay parallel to the table. E
2. Repeat the rocking motion and notice how a swirl develops on both ends of the clay, mimicking the curved horns of a ram. F Continue wedging for at least six repetitions to ensure any air bubbles have been popped.
3. To finish wedging, roll the clay farther back on successive backward rocking motions. This will tuck the smaller wings of clay back into the center, resulting in an elongated cylinder of clay. Using both hands, pat the ends down, creating a ball. G The clay is now ready for the wheel.
RECYCLING YOUR CLAY
Clay is relatively cheap as a raw material, ranging between $0.40 and $1.00 per pound. When compared to the price of something like gold, which currently sits at over $16,000 per pound, it would seem we don’t need to worry too much about wasting material. If clay is so cheap, then why is it still important to recycle it? I could go into the environmental cost of clay mining, or the space it might take up in a landfill, but the best reason is that clay is just so darn easy to recycle.
You have probably already started recycling your clay by re-wedging failed pieces that come off the wheel. These can be put to the side to dry and then reused at the end of your throwing session. Another easy method is to collect slurry from your splash pans in 10-gallon plastic buckets. Let the clay mixture settle for a week and then pour off excess water. Mix with a paddle drill for ten minutes before spreading it out on plaster slabs. Within a few days you will be able to wedge and use the clay again on the wheel. If you don’t have access to plaster, try pouring the mixture into old pillowcases. Tie the ends and leave them out on a concrete surface in the sun until they are in a wedgeable state.
If you are a full-time potter, purchasing a pug mill might be a good option. Many current models will take both wet and dry scraps and mix them to the right consistency before de-airing and extruding the clay in a workable state. No matter which method you choose, make sure to separate clays by color and temperature. The cleaner and more streamlined your recycling process is, the less likely you are to have cross-contamination. I’ve seen many good pots turn into seconds when a handful of high-iron stoneware gets thrown in the porcelain bucket. For more information on pug mills, see the reference section at the end of the book.
THROWING
While the exact origin is under debate, there is firm evidence that potters started using the wheel to make vessels thousands of years ago. From ancient hand-turned wheels to the modern electric wheel, people have used a spinning wheel to help shape clay into a pot for generations. This section will highlight the physical forces and techniques that make wheel-throwing possible.
THE PHYSICS OF CENTRIFUGAL FORCE
Before we jump into technique, let’s think about the physics behind a spinning wheel. As your wheel starts in motion, centrifugal force begins to build. The faster the wheel spins, the more force is generated. If you are the center of the wheel, the force is mild. However the farther away an object, in our case clay, moves from the central axis of the wheel, the more outward pressure it experiences. A childhood illustration of this point is the merry-go-round. Think back to the times where you were spun into dizziness by your friends on the playground. If you got too dizzy, you could try to hop off and be shot out like a cannonball, or you could get to the center of the wheel and wait until the merry-go-round stopped.
Potters harness this same principle to exert force on softly spinning clay. As your wheel’s velocity encourages the clay to move outward, the countermovement you generate with your hands forces the clay to go up. This dance between countermovement and outward force is one that potters have broken down into four stages: centering, opening, pulling the walls, and shaping.
All stages of throwing occur with you sitting upright with your forearms resting on a splash pan or firmly braced against your knees and torso. By putting your hands together on the clay, you are initiating a three-point stance, which is excellent for strength and stability (see here for more on correct posture and body mechanics). As you move through the stages of throwing, allow your body to be relaxed but also firm in the positions. The movements needed for throwing are more about balance and finesse than aggression and raw strength. If you feel uncomfortable from muscle tension, then you should consider readjusting your body. Lastly, don’t forget to breathe in a steady, regulated manner. When first learning to throw, I would unconsciously hold my breath from time to time, which created undue stress and tension in my body.
CENTERING
Centering is the process of aligning clay particles around the central axis of the wheel. The process starts after your clay has been stuck to the wheel head or bat, so go ahead and do that before you start the wheel spinning. Then adjust your wheel speed. Your wheel should be set to medium or three-quarter speed throughout the centering process.
Note: When describing hand positions in this section, I will refer to the numeric positions of an analog clock. The positions I will be teaching apply when your wheel is spinning counterclockwise. Your hands will often be positioned at three or six o’clock so that the clay spins away from your touch. If your hands rotate past six o’clock toward twelve o’clock, you will feel friction with the clay spinning toward your hands. If your wheel is spinning clockwise, your hands will be positioned between six and nine o’clock. The idea remains the same—you want to decrease friction by having the clay spin away from your hands.
1. Coning up: Wet your hands and the surface of the clay. Apply pressure with the section of your palms of both hands, including your ring and pinkie finger area. A Squeeze inward with your hands at three and nine o’clock until the clay starts to move upward. B Continue until you form the clay into a cone shape. (Centering will be one of the only times your hand positions will be placed in the range between six and twelve on the clock.)
2. Coning down: Before touching the clay, extend your left hand as you would when shaking hands. Ball your right hand into a fist so that the fleshy lower part of your palm is compressed. C These hand positions will continue as you cone down. Place your left hand at nine o’clock and apply downward pressure with your balled-up fist. Push the clay down with your top hand as you collect the clay with light pressure from your left hand. Continue to push down until you have a well-formed lump of clay that is not wobbling.
Correcting the “mushroom”: When centering, it is common to push too hard with your top hand, which will cause a mushroom shape to be created. To counteract this, apply more pressure with the palm of your left hand. Achieving balanced pressure between your hands will take practice. Knowing how much pressure to use and when to stop applying pressure are key principles of centering that you will master over time.
3. Centering low or high based on your form: To finish the centering process, get ready for the next steps based on your form. When throwing a vertical form, you will center the lump of clay into a shape that is taller than it is wide. When throwing a horizontal form, you will center the lump of clay into a shape that is wider than it is tall. D Practice changing the proportion of your centered lump of clay to become comfortable making a variety of shapes.
OPENING
After your clay is centered, you’ll start the opening process. Wet your hands and the surface of the clay. In general, less water will be needed after the centering stage is complete. Set your wheel to medium speed and maintain this speed throughout the opening process.
1. Finding the “eye of the storm”: Think about your clay as if it is a hurricane funnel spinning around a still eye. Extend the pointer and middle finger of your right hand. Rest the pads of these fingers slightly to the right of center of this eye. Move your fingers toward the eye, feeling for a place where there is very little friction. This place of no friction is located at the central axis of the wheel. This is where you will apply downward pressure to open the pot. Before pushing down to open the form, brace your right hand by placing your left hand under your right wrist or underneath the right palm. E This links your hands together and makes the opening process more stable. A common variation is to open with both thumbs instead of your pointer finger. F
2. Opening down: Push down with your outstretched fingers until you are 1/4 to 1/8 inch from the wheel head. If you have trouble judging the depth, stop the wheel and insert a pin tool into the center of the clay. Slide your finger down the tip of the tool to the clay surface and then pull out the tool. The exposed surface of the pin tool will be the depth of your foot. This depth will vary depending on the form you are making and the height of the foot you want to make.
3. Opening out: With the depth of your opening set, you will now focus on creating the interior width of your form. Keep your left hand linked with your right for support and pull outward with your right pointer and middle finger. G Apply outward pressure with the pads of your fingers, making sure the rest of your finger is in an upright, vertical position. Pull outward to your desired width. This will change depending on your form. Cups might only need a two-inch opening while a bowl might be four inches. As you open outward, think about a curved versus flat interior of the form. I’ll talk in-depth about this difference in Chapter 3 (see here).
4. Compressing the bottom: The last step of opening is compressing the bottom of the interior. This can be done with the pads of your fingers, a sponge, or a rib. Remove any interior texture and smooth over the hole you made when checking the thickness of your base. Remove any water that might have accumulated in the opening process. Inadequate compression or excess water can lead to S cracks in the base of your pot.
PULLING THE WALLS
The next step in the process will be to form the walls of the piece. Before you start to do this, decrease your wheel speed to medium or just below. Apply a wet sponge to the inside and outside of your clay at three o’clock. Do not oversaturate your clay as this will make it difficult to pull the clay upward. The hand positions for pulling are extended pointer and middle fingers on both hands.
1. Match the “dancing partners”: Place the pads of your lefthand fingers at the interior base of the form at three o’clock. Match their position on the outside with the fingers of your right hand. As the clay slides past your fingers, apply moderate pressure with your outside hand. The inside hand should act as a wall that can be pushed against. H The clay will want to move upward as you counteract the centrifugal force generated by the spinning wheel. With your fingers moving like dance partners, apply exterior force and raise your hands up the form at an even speed. I
2. Pull up: When just beginning to throw, you might be hesitant to push hard with the outside hand. However, to effectively pull the walls, you will need to raise the clay with direct and firm pressure at the wheel head. As you pull upward, slightly decrease pressure and match the speed of your pull to speed of wheel. A successful pull will allow you to touch the clay in all places for a full rotation. Pulling up too fast will create a corkscrew in your pot, throwing it off center. (See the line exercise in Chapter 2 to help you match your pulling speed to the speed of the wheel.) As you approach the rim of the pot, decrease your pressure and slowly take your hands way. The goal for the number of pulls should be to reach your desired height after three. This is a goal, so don’t worry if it takes four or five, but focus on developing your skills in a smooth, deliberate manner.
3. Compress the rim: After your first pull you will need to compress the rim. Start by making a pinching motion with your left thumb and pointer finger. Place them on the rim and let the clay slide through your fingers. The left hand will apply pressure to the sides of the pot as your right outstretched pointer finger applies downward pressure. J You will need to compress the rim after every subsequent pull. Pay attention to the shape of the rim. A rim that is too sharp or angular will chip. A round rim will be the most functional, but you might tilt it inward or outward to establish a stronger form. Consider using a chamois cloth or sponge to make a smoother, more well-defined rim.
SHAPING
The hand positions (extended pointer and middle fingers) and wheel speed (medium or less) for shaping are the same as for pulling. When applying water to the pot, be aware of the location you put it. As you push the form into shape, too much water on the underside of a curve might cause the form to collapse.
Shaping outward: When shaping, the inside hand takes the lead and the outside hand acts like a wall that can be pushed against. To initiate a curve, press outward at the location you want the curve to start. K Continue with outward pressure moving upward to the middle of the curve you desire. Think about establishing your curve in a slow progression. You are stretching the clay as you push outward, so sharp, quick movements might cause the form to collapse. From here, your options will vary greatly based on your form.
Working with a rib: When shaping, it can be helpful to hold a rib on the outside or inside of the pot. L This replaces the pressure you apply with your fingers, which enables a smooth, compressed surface. Try using a wooden, rubber, or metal rib to experiment with how crisp you want the surface to be. The denser the rib, the more compressed the surface will be.
Shaping inward or collaring: After initiating an outward curve, you might decide you want to change the top of the curve into a bottle-style neck or lip. To collar the clay, apply slight pressure with the side of your thumb and pointer finger to shape the clay inward. Let the clay slide through your fingers, and always move in an upward direction. If you find your fingers start to chatter or the clay wobbles excessively, then wet the clay with a damp sponge to decrease friction. After collaring the clay, you might make a few upward pulls to even out the walls. Pots that are off center will be harder to collar, and a diagonal crease might form where the form is torqued. If this occurs, push out against a rib to smooth out the crease. Finish the shape by compressing the rim with a chamois cloth or your fingers.
Finishing details: In this section I am talking about the general notion of shaping. The methods described are a starting point for making a unique and interesting form. When finishing pots, consider how you might articulate the lip, body, or foot of the form, and how you might use proportions or decoration to establish a focal point on the form. In the chapters that follow, you will learn more about altering, trimming, texturing, and many other techniques that help define your individual voice in clay.
REMOVING THE POT
After you have finished the form, the final step is to take the pot off the wheel. If you are using a bat, simply lift up to remove the bat from the pins. If you are throwing on the wheel head, you will need to cut the pot off the wheel. To do this, stop your wheel and drag a metal wire underneath the pot. If the pot is stuck, add water to the surface of the wheel head and drag the wire again. This will pull water under the pot and allow you to move it easily.
In the course of removing your pot, you might notice the form warp as you pick it up. This is normal and can be corrected after you put the pot down on a ware board. To correct the warp, rotate your hands 180 degrees on the base and lift upward like you are going to pick the pot up again. This will counteract the initial warp starting at the base and concluding at the rim. It might be tempting to only fix the lip of the pot, but this is a superficial change that will come undone as the pot dries. Realigning the foot of the pot is a more successful way to correct a warp.
Looking Inside the Pot
This series of cross-sections shows the progression a lump of clay goes through to become a cup. I encourage you to cut your pots in half regularly to check wall thickness and better judge the progress you are making with each stage in the throwing process.
