pottery, one concept per page
Twenty-four lessons on clay bodies, wedging air out of the lump, the wheel and centering, opening the clay and pulling walls, the stages of clay from slip to bone dry, trimming the foot, score and slip, handles, drying without cracking, bisque firing, the kiln and firing schedules, glaze as melting glass, dipping against pouring, wax resist, glaze defects, pinch coil and slab, lids and spouts, reclaiming clay, studio tools, studio safety, and a first studio visit.
One concept, one diagram, one honest page. That's a lesson.
pottery, one concept per page
Twenty-four lessons on clay bodies, wedging air out of the lump, the wheel and centering, opening the clay and pulling walls, the stages of clay from slip to bone dry, trimming the foot, score and slip, handles, drying without cracking, bisque firing, the kiln and firing schedules, glaze as melting glass, dipping against pouring, wax resist, glaze defects, pinch coil and slab, lids and spouts, reclaiming clay, studio tools, studio safety, and a first studio visit.
Set in Space Grotesk, Inter and JetBrains Mono (SIL Open Font License).
Every fact in this book is as the primary source states it, fetched and read during this build: the Wikipedia articles Pottery, Ceramic art, Kiln, Stoneware, Earthenware, Porcelain, Pinch pot, Slipware and Crazing, plus the Colorado 4-H Ceramics Manual Unit 1, Hand Construction with Stoneware or Earthenware, and Unit 8, Wheel Throwing, from Colorado State University Extension, and the excerpt of Vince Pitelka's Clay: A Studio Handbook, 2nd edition, published by Ceramic Arts Network, all cached at build time and cited in each lesson's source line. This is general information about how pottery works, not professional advice; pottery cannot be run to test a book, and where a practice could not be demonstrated, this book states the source instead of inventing a demo. Where two sources state different numbers, each is stated as its source states it, and every figure is attributed to its source. Practical rituals this book states as its own plan (the order of the lessons, the practice asks, the first studio visit checklist) are labeled as this book's plan and rest on mechanics from those sources. No product recommendations, no brand names beyond named sources, no prices. An independent guide; not affiliated with or endorsed by Wikipedia, Colorado State University Extension or Ceramic Arts Network. No facts are sourced from Reddit, forums, vendor blogs or search engines.
Your purchase is for personal use only. You do not have redistribution rights: please do not share, resell, or republish this book or its pages.
© 2026 Steve Hodgkiss. All rights reserved. Personal use only; no redistribution rights.
Edition 1.0 · stevehodgkiss.net
Contents
Per the Colorado 4-H Ceramics Manual Unit 1, most premixed clay is packaged in 25 to 50 pound moist blocks, and before hand building or throwing on the wheel the clay must be wedged, kneaded, to condition and to drive out the trapped air bubbles; you cut off an amount you feel comfortable with, 1 to 2 pounds for beginners is ideal, form a ball, flatten it, grasp the edge with both hands and fold it into the center of the ball with a downward push, give the ball a quarter turn and repeat, and do not be surprised if you must spend 15 minutes or longer on this process, because you can never over-knead the clay; air bubbles can create problems, causing the piece to explode in the firing kiln; and per the Pitelka handbook excerpt, every air bubble provides the beginning of a fracture or separation, wedging or pugging in a de-airing mill mixes and homogenizes the clay and eliminates air, and wedging is an entirely different process from kneading bread dough because the objective is to eliminate air.
Wedging
Before anything else the lump is wedged: kneaded to drive out trapped air, fold and downward push, a quarter turn at a time, for 15 minutes or more.
You cannot over-knead clay. Air is fatal in the kiln: bubbles can make the piece explode in firing, and per Pitelka every bubble is the beginning of a fracture.
It is not kneading bread: the goal is eliminating air, not folding it in. Beginners start with 1 to 2 pound balls.
Watch a wedged lump this week for the spiral; that pattern is the air leaving.
Per the Pitelka handbook excerpt, the purpose of the centering process is to shape and compress the clay in a smooth, symmetrical mass perfectly centered on the wheel head, and proper centering is essential to good throwing; effective centering utilizes the weight of your upper torso and the powerful muscles in the hips and back rather than muscular strength in the arms; you move your stool very close to the wheel head, lean your elbows against your thighs, bear down on both elbows with the weight of your upper torso, and roll your hips forward so the base of your right palm applies the primary force; the primary force of centering is across the wheel head, not down against it; you maintain a fairly wide footprint at the base of the lump; and you always release pressure gradually while the wheel is still turning, because pulling your hands away suddenly will throw the lump off-center or damage the vessel; and per the Colorado 4-H Unit 8, centering your clay is easier if the wheel is spinning more quickly.
Centering
Centering makes one smooth, symmetrical mass, dead center on the wheel head, and proper centering is essential.
The force is your torso, hips and back, not your arms: stool close, elbows locked on thighs, roll the hips forward, press across the wheel head, not down.
Release gradually, wheel still turning; sudden hands throw the lump off-center. And centering is easier at speed.
Press your palms together at a desk this week and feel the cross brace.
Per the Colorado 4-H Ceramics Manual Unit 1, clay should be handled differently during varying stages from wet to bone dry, and clay should be dried slowly to avoid cracking; the manual's moisture stages of clay are: slip, a liquid clay used for slipping and scoring to join pieces, which acts like glue; sticky wet, clay that is too wet to be used because it sticks to your hands or the table; wet, the consistency best for wedging, building, and forming with pinching, coiling, rolling slabs, or throwing on a wheel; suede, clay that has stiffened up but is still workable for stamping, impressing, carving, slipping and scoring; soft leather-hard, clay that is still flexible and can hold its shape; leather hard, clay that holds its shape, is not easily changed, and is workable for trimming; hard or stiff leather-hard, a more advanced stage of drying that cannot change its shape without breaking; dry, clay that has started to change color; and bone dry, brittle clay that has completely changed color, has no moisture, is no longer cool to the touch, and is ready for underglaze decoration or to be bisque fired.
The stages of clay
Clay climbs a ladder of stages: slip, liquid and gluey; sticky wet; wet, best for wedging, building, throwing; suede, stiff but stampable and carvable.
Leather hard holds its shape and is the stage for trimming; hard leather-hard breaks before it bends.
Top rung: bone dry, brittle, no moisture, no longer cool to the touch, ready for bisque.
Leave a ball to dry this week and touch it daily; feel the rungs.
Per the Wikipedia article Pottery, bisque, or biscuit, refers to the clay after the object is shaped to the desired form and fired in the kiln for the first time, known as bisque fired or biscuit fired; this firing results in both chemical and physical changes to the minerals of the clay body; per the Wikipedia article Kiln, ceramics require high temperatures for chemical and physical reactions to occur that will permanently alter the unfired body, and after a first firing, glazes may be used and the ware is fired a second time to fuse the glaze into the body; firing includes sintering, which heats the clay until the particles partially melt and flow together, creating a strong single mass, and through firing the pores are reduced in size, causing the material to shrink slightly; and per the Colorado 4-H Unit 1, before you load the kiln for bisque firing you must be sure the clay is dried completely so it is solid with no cracking, removing any debris or imperfections.
Bisque firing
Bisque is the first firing: shaped clay, fired once, chemically and physically changed for good.
Heat makes the particles partially melt and flow together into one strong mass; the pores close, so the ware shrinks slightly.
Load it bone dry and clean of debris; a second firing will come later, to fuse the glaze into the body.
Pick up bisque ware this week if you can: chalky, porous, ready for glaze.
Into the glaze
Per the Wikipedia article Pottery, glaze is a glassy coating on pottery, used for decoration, to make the item impermeable to liquids and to minimize the adherence of pollutants, applied to the biscuit ware and then glaze fired, causing the glaze to melt and adhere to it; the article states glaze may be applied by spraying, dipping, trailing or brushing on an aqueous suspension of the unfired glaze, that the color after firing may be significantly different from before, and that the foot is left unglazed or refractory spurs are used to keep ware from sticking to the kiln furniture; the Pitelka handbook excerpt lists wax resist for footrings and the use of hot wax among its studio practices and gives glaze faults and glaze fit their own sections; and per the Wikipedia article Crazing with the article Earthenware, crazing has historically described a network of fine cracks on the surfaces of glasses and ceramics, and earthenware's glaze would craze over time, letting the porous body absorb moisture and odors, while the Colorado 4-H Unit 8 judging sheet asks whether the glaze is applied evenly and free of drips, bubbles, and areas too thick or thin.
- 01What glaze is
- 02Glaze defects
Per the Wikipedia article Pottery, glaze is a glassy coating on pottery, and reasons to use it include decoration, ensuring the item is impermeable to liquids, and minimizing the adherence of pollutants; a glaze may be applied to the biscuit ware, and the object is then glaze fired, or glost fired, causing the glaze to melt and adhere to it, and depending on the temperature schedule the glaze firing may also further mature the body; glaze may be colorless, especially over painting, or colored and opaque, and is perhaps the most common form of decoration, which also serves as protection to the pottery; per the article Earthenware, because of its porosity, fired earthenware with a water absorption of 5 to 8 percent must be glazed to be watertight; and per the Colorado 4-H Unit 1, food and drink containers in stoneware must be glazed inside, because hobbyists can rarely fire stoneware to a point where it is completely vitreous.
What glaze is
Glaze is a glassy coating: decoration, impermeability, and protection from pollutants in one melted skin.
It goes onto biscuit ware, then the glaze firing melts it onto the pot, maturing the body further.
For earthenware, glaze is not optional: the body drinks water, so only glaze makes it watertight, and stoneware cups are glazed inside.
Run a finger over a glazed bowl and its bare foot this week: glass, then stone.
Per the Wikipedia article Crazing, the term crazing has historically been used to describe a network of fine cracks on the surfaces of glasses and ceramics; per the Wikipedia article Earthenware, earthenware exhibited significant technical weaknesses: the body was easily chipped, the glaze would craze over time, and the underlying porous ceramic would absorb moisture and odors; per the Pitelka handbook excerpt, its glazes chapter gives glaze faults their own section, covering unwanted opacity or surface mattness and glaze problems associated with glaze fit, with thermal expansion and glaze fit and an easy test for glaze fit listed; and per the Colorado 4-H Unit 8 judging guidelines, judges look at whether the glaze is applied evenly, and whether there are any drips, bubbles, or areas where the glaze is too thick or thin.
Glaze defects
Crazing is a fine network of cracks in the glaze, the classic fault: on earthenware it lets the porous body drink moisture and odors.
Its root is glaze fit: Pitelka files glaze faults under thermal expansion, with a simple fit test beside them.
The everyday checks: drips, bubbles, glaze too thick or too thin, coats laid unevenly.
Inspect a glazed cup in raking light this week: cracks, drips, bare patches.