The Clay Hole guide to round forms

How to throw open and closed spheres

A sphere is the form that punishes everything you have been quietly getting away with. A crooked base. A wall that is thin on one side. Half a pound of water you did not need. None of it shows on a mug. All of it shows on a ball.

Two forms live on this page. An open sphere is a round pot with an opening in the top. A closed sphere is a round pot with no opening at all, held up from the inside by air you sealed in on purpose. They are thrown almost identically right up until the last thirty seconds, and the last thirty seconds is where nearly everybody loses one.

An illustration of a potter steadying a smooth pale sphere on the wheel with a rib, next to a table holding a finished orange sphere and an open bowl
9videos, from six potters who are not us
2videos, the two that matter most
4checklists you can tick with one knuckle
14ways it goes wrong, and the cause of each
4ways it goes wrong on the first night
Everything on this page, in order
01Why this page is words and video 02Open, closed, and what counts as a sphere 03Before you sit down 04Collaring, the move both forms rest on 05The open sphere, step by step 06The closed sphere, step by step 07What the trapped air is actually doing 08Off the wheel: the hole, the drying, the foot 09It went wrong. Find which one 10What attempt one actually looks like 11Every word we just used 12Questions we get at wheel side
Everything on this page, in order
01The whole idea, in six lines 02Before you sit down 03Collaring, the move both forms rest on 04The open sphere, step by step 05The closed sphere, step by step 06Off the wheel: the hole, the drying, the foot 07It went wrong. Find which one

Everything we know about throwing a round form, in order.

01 · The whole idea

A sphere is a cylinder you push out and then squeeze shut

Both forms on this page are the same pot until the last thirty seconds. Throw a cylinder taller and narrower than the ball you want, push the middle out, then collar the top down. An open sphere stops at a neck. A closed one keeps going until the hole is gone and the air you sealed in holds the wall up.

  1. 1Open a floor about a third of the finished width. A round pot on a wide base reads as a ball on a plate, and you cannot narrow a floor later.
  2. 2Put the widest point a touch above the middle. Dead center is correct and slightly dull. Judge it from the side, never from above.
  3. 3Slow the wheel right down to collar. Roughly half throwing speed. The spin is trying to pull the neck back open while you close it.
  4. 4Get the wall even before you close anything. On a closed form you never feel the inside again, so every thin patch you leave is permanent.
  5. 5Sealed air is what holds a closed pot up. Press the top and it swells fuller, squeeze the sides and it grows taller. You steer air, not clay.
  6. 6Every sealed pot gets a hole before it is fired. No exceptions. Expanding air and steam have to go somewhere.

The two videos below are not ours and we are not paid for them. Each loads only when you tap it, so no player and no YouTube cookies arrive until you ask.

01 · The reason this page exists

Read it, watch it, then read it again with muddy hands

There is a reason we did not just post nine videos and call it a page. Video and writing are good at completely different jobs, and a sphere happens to need both.

What video does better

It runs at the speed of the clay

Nobody can write down the speed of a collar. You have to watch a pair of hands close a hole slowly enough that the wall does not fold, and see how little happens per second. Nine paragraphs will not do what nine seconds of footage does. Pressure, angle, pace, and the moment a potter stops and just lets the wheel run: all of that is motion, and motion belongs on video.

What writing does better

You can glance at it

A video is a line. You watch it from one end to the other, and you cannot scan it. Finding the third thing somebody said at 4:12 means dragging a scrubber around with a thumb that currently has clay on it. Eleven numbered steps can be read in two seconds, in any order, off a phone propped against a water bucket. When your hands are busy and the pot is drying, that is not a small difference.

And the part nobody enjoys hearing

Watching somebody who is good at something feels like learning. It is one of the better feelings available on the internet, and it is mostly a lie. Recognizing a move is not the same as owning it, and video is very good at handing you the first while you assume you got the second.

Writing forces the reason into actual words. A video can show you a slow wheel for eleven minutes and never once tell you the wheel is slow because the spin itself is trying to pull the neck back open while you close it. Once somebody says that out loud, you stop copying a hand position and start solving a problem.

So this is the order we would use

Three passes, not one
  • 1Read the steps first, before you watch anythingSo the words already mean something. When the video says collar, you are watching the hands instead of decoding the sentence.
  • 2Watch one video all the way through, at real speedNo pausing, no scrubbing. You are looking for pace and pressure, and both of those disappear the moment you start stopping it.
  • 3Put the list back on your phone and go do it badlyThis is the pass that actually goes in. The first two were setup. Expect to lose the first few, and read the list again between attempts rather than after all of them.

Every step list below is built for that third pass. One idea per line, a Just the steps button that strips out the explanations when you no longer need them, and tick marks big enough to hit with a knuckle.

None of the videos on this page are ours. We did not make them, we are not paid for them, and we picked them because they teach this particular thing well. Every one loads only when you tap it, so no video player and no YouTube cookies arrive until you ask for them.

02 · Two forms, one shape

Open, closed, and what actually reads as round

Almost everything on this page applies to both forms. The difference is one decision made in the last minute on the wheel, and it changes what you are allowed to do afterward.

1 2 3 4 5 6 7
  1. 1A narrow base. A round pot on a wide flat disc reads as a ball on a plate. Aim for a base around a third of the finished width.
  2. 2The widest point, a touch above the middle. Dead center is geometrically correct and slightly dull in the hand. Raise it and the pot lifts.
  3. 3The opening, on an open sphere. Collared down to a neck, compressed, and finished while you can still reach the inside of it.
  4. 4No opening at all, on a closed sphere. The clay is welded shut across the top while the wheel is still turning.
  5. 5An even wall, decided before you close it. Once it is sealed you never feel the inside again, so every thin patch you left is now permanent.
  6. 6The trapped air. It pushes outward everywhere at once, which is the only reason a sealed form can be shaped from the outside without caving in.
  7. 7The hole you add later. A closed form gets pierced once it is firm. A genuinely sealed pot only visits a kiln one time.

Open sphere

Round body, small mouth

Bud vases, ginger jar bodies, round bottles, moon-ish vases. You throw a cylinder, push the belly out, then collar the top down to whatever opening you want. The inside stays reachable for longer, which makes this the one to learn first.

Closed sphere

Round body, no mouth

Rattles, floats, garden orbs, salt shakers, lidded jar bodies, and anything you plan to carve or pierce later. You collar the top all the way to nothing and let the sealed air do the job your inside hand used to do.

The true sphere

Round on the bottom too

A ball with no flat anywhere is a closed sphere plus a second job: trimming the base round while the pot sits upside down in a chuck. Everyone who wants a perfect ball ends up here eventually. Section 08 covers it.

03 · Setup

02 · Setup

Six decisions you make before the wheel is switched on

A sphere takes more passes than a cylinder does, and every pass costs you water, structure and patience. Most of the ones we watch fail were already in trouble before anybody touched a pedal.

Use less clay than feels right

One and a half to three pounds. About a large orange up to a grapefruit. Small forms collar shut easily and big ones fight you the whole way, so the ball you actually want is the one after the six you practiced on.

Pick a clay with some tooth

A bellied wall has to stand up while being pushed sideways, and a body with grog or specks in it holds that shape better than a slick one. Our #16 Porcelain is beautiful and the least forgiving thing in the building. Save it for sphere number twenty.

Throw on a bat

A round form needs to firm up before it gets handled, and lifting a soft sphere off a wheel head with your fingers is how a round pot becomes an oval pot. Throw on a bat, pop the bat off, walk away.

Ribs are not optional here

A flexible metal rib for pushing the belly out and smoothing the curve, a wooden rib for the final profile, a needle tool, and a chamois or a strip of soft plastic for the rim. Once the form closes in, a rib is the only thing that still reaches.

Decide your water budget now

Every collaring pass and every belly pass soaks more water into the wall. Spheres are lost to sogginess far more often than to bad hands. Use the least water that lets your fingers slide, and stop the moment the surface starts to look glossy.

Know what you are making before you open

Open or closed changes how much clay you leave near the rim and how wide you open the floor. Deciding halfway up is how you end up with a form that is neither, with a wall too thin to close and a mouth too small to reach into.

  1. 1One and a half to three pounds. A large orange up to a grapefruit. Small forms collar shut without drama, and you can throw six of them in the time one big attempt takes to fail.
  2. 2A clay with some tooth. Grog or specks hold a bellied wall up while you push it sideways. Our #16 Porcelain is the least forgiving thing in the building, so save it for sphere number twenty.
  3. 3Throw on a bat. Lifting a soft sphere off a wheel head with your fingers is how a round pot becomes an oval pot. Pop the bat off and walk away.
  4. 4Ribs, a needle tool, and something soft for the rim. A flexible metal rib for the belly, a wooden rib for the final profile. Once the form closes in, a rib is the only thing that still reaches.
  5. 5Use the least water that lets your fingers slide. Spheres are lost to sogginess far more often than to bad hands. Stop the moment the surface starts to look glossy.
  6. 6Decide open or closed before you open the clay. It changes how much clay you leave near the rim. Deciding halfway up gives you a form that is neither.

If you have never thrown a cylinder you can be proud of, start there

Every sphere on this page begins as a cylinder. Nothing here fixes a wall that is thick at the bottom and thin at the top, it just hides it until the belly goes out and the thin part tears. Our full wheel guide covers centering, opening and pulling in detail. Read the wheel guide or run the tap centering practice tool first.

Nothing on this page fixes a wall that is thick at the bottom and thin at the top. It just hides it until the belly goes out and the thin part tears. Read the wheel guide first if your cylinders still surprise you.

04 · The move everything else depends on

03 · The move everything else depends on

Collaring: making a circle smaller without wrecking it

Every other move on a wheel makes clay travel outward or upward. Collaring is the one that makes it travel inward, and it is the reason both of these forms are possible. Learn it properly and an open sphere becomes a shape you can aim at instead of a shape you occasionally get.

Here is the part that explains most beginner failures. When you squeeze a spinning circle smaller, the clay in it has nowhere to go but into a shorter, fatter ring. The wall thickens. The rim thickens fastest of all. And the wheel is spinning that whole ring outward the entire time you are trying to pull it in. Slow hands and a slow wheel are not politeness. They are the only way the clay stays ahead of the physics.

Every other move on a wheel pushes clay out or up. Collaring is the one that pulls it in, and both of these forms rest on it. Squeeze a spinning circle smaller and the same clay has nowhere to go but into a shorter, fatter ring, so the wall thickens and the rim thickens fastest of all. The wheel is fighting you the entire time. That is why slow hands and a slow wheel are not politeness.

Collaring, in order 0 of 7 ticked
Collaring, in order 0 of 6 ticked

Two potters, two ways of explaining the same squeeze

One is quiet and precise and shows you exactly what the hands do. The other talks the whole way through and tells you why. If collaring has never clicked for you, watch the one that matches how you learn, then watch the other one anyway.

Watch the hands, not the pot

Nobody can write down the speed of a collar. Watch how little the clay moves per pass.

Florian Gadsby17 min “How to Collar in Clay — A Beginner’s Guide” The cleanest demonstration of the hand ring we have found, and he shows it going wrong too.
Florian Gadsby17 min “How to Collar in Clay — A Beginner’s Guide” The cleanest demonstration of the hand ring we have found, shot close enough that you can see how little the clay moves per pass. He also shows collaring going wrong, which is more useful than watching it go right.
Earth Nation Ceramics22 min “collaring and choking for beginners” Long, chatty and worth every minute. This is the one that explains the reasoning: why the wheel slows, why the rim thickens, and why you have spent the last year pushing clay out and now have to do the opposite.

05 · Round with a mouth

04 · Round with a mouth

The open sphere, step by step

Learn this one first. You keep access to the inside for most of it, you can undo a bad belly, and if the neck goes badly you still have a vase instead of a puddle.

The whole form is one idea: throw a cylinder that is taller and narrower than the ball you want, then push the middle out until it is neither. Bellying trades height for width, so a pot that already looks like the right size before you belly it will be a squat one afterward.

Open sphere, in order 0 of 11 ticked
Open sphere, in order 0 of 7 ticked

Three versions of the same pot

One with no talking at all, one built around ribs, and one at a scale most of us are not ready for. Watching the same form made three different ways is the fastest cure for thinking there is a correct way.

Ingleton Pottery7 min “Making / Throwing a Spherical shaped Pottery vase on the wheel” Almost no talking, no editing and no ceremony. Start here if you want to see how long the belly actually takes and how unhurried the hands are. Six and a half minutes, start to finish, in real time.
Red Circle Pottery9 min “Throwing a Perfectly Shaped Sphere Pottery Vase on the Wheel” This is the rib video. Watch how much of the final curve comes from a rib held steady against the outside rather than from fingers, and how the profile tidies itself up in about two passes once the rib goes on.
Hsin-Chuen Lin10 min “2. Throwing a Large Closed Form / Vase” A big belly and a small mouth, made by somebody who has done it several thousand times. Note the title: plenty of potters use closed form to mean a narrow neck rather than a sealed pot. It is worth knowing both meanings before you go searching for more videos.

06 · Round with no mouth

05 · Round with no mouth

The closed sphere, step by step

The first eight minutes are almost identical to the open sphere. Then you keep going with the collar until the hole is gone, and everything about how you work changes.

The moment the top seals, you stop being a potter with an inside hand and become somebody shaping a small balloon. That is not a metaphor we are stretching for fun. It is exactly what is happening, and section 07 explains why it works.

The moment the top seals you stop being a potter with an inside hand and become somebody shaping a small balloon. The air cannot leave, so it pushes back evenly everywhere at once, which is the job your inside hand used to do.

Closed sphere, in order 0 of 10 ticked
Closed sphere, in order 0 of 6 ticked

The one rule that is not negotiable

A sealed pot needs a hole in it before it is fired. Steam and expanding air have to go somewhere, and a hollow form with nowhere to vent comes apart in the kiln and takes its neighbors with it. You pierce it later, once it is firm. If you are ever unsure whether a piece of yours is sealed, ask before you put it on the shelf.

A sealed pot needs a hole in it before it is fired. Water turns to steam inside a kiln and steam has to go somewhere, and a hollow form with nowhere to vent is a pot that comes apart and takes its neighbors with it. You pierce it later, once it is firm, and section 08 covers exactly where and when. If you are ever unsure whether a piece of yours is sealed, ask before you put it on the shelf.

Watch somebody close one

The closing itself takes about fifteen seconds and it is the whole reason to watch video rather than read about it. Look at the wheel speed, and look at how much of the rim they had left to work with.

Ingleton Pottery4 min “Pottery Throwing Techniques 3 : Throwing a closed in / enclosed form pot on the wheel” Four minutes and no fuss. Watch the last minute: the seal happens and the pot becomes a different object.
Ingleton Pottery4 min “Pottery Throwing Techniques 3 : Throwing a closed in / enclosed form pot on the wheel” Four minutes and no fuss. If you only watch one thing on this page, watch the last minute of this one. The seal happens and then the pot immediately behaves like a different object, and you can see it happen.
Earth Nation Ceramics10 min “How to throw an Enclosed form on the wheel (intermediate)” The teaching version. He explains what the air is doing while he does it, which is the bit almost every other enclosed form video leaves out, and he is honest that this sits above beginner level.

07 · The part nobody explains

What the trapped air is actually doing in there

A closed sphere is not standing up because the clay got stronger. It is standing up because you sealed a fixed amount of air inside a bag of mud, and that air cannot leave.

Press on the outside anywhere and you squeeze that air into slightly less room. The pressure rises. And because pressure in a sealed space pushes equally in every direction, it shoves back against the entire inside surface at once, evenly, at exactly the moment you need it to.

That is the job your inside hand used to do. Except now it is everywhere simultaneously, it never gets tired, and it does not have knuckles.

It lets the wall go thinner

Support from the inside at every point at once means a sealed wall can be finer than an open one of the same size. This is why thrown ceramic floats and rattles can be so absurdly light.

You shape it by moving air, not clay

Press down on the top and the volume drops, the pressure rises, and the sides swell out. Squeeze the sides and it grows taller instead. You are steering, and the clay is following.

One pinhole switches it all off

The whole effect depends on the seal. A hole the width of a needle anywhere in the form and the pot goes limp under your hands within seconds, which is a very fast way to find out where your thin spot was.

And the same physics turns on you in the kiln

Air expands when it gets hot, and the water still living in that clay turns to steam. Inside a sealed form, both of those need somewhere to go and there is nowhere. So you make a hole once the pot is firm, and the trick that was holding your ball up at room temperature stops being a problem at cone 05.

Worth separating this from the myth it gets confused with. A small air bubble trapped in a wall does not blow pots up in a kiln, whatever you were told, and we have a whole page about that. A sealed hollow form with no vent is a completely different animal, and that one is real.

08 · The half nobody films

06 · The half nobody films

Off the wheel: the hole, the drying, and the round bottom

Plenty of spheres survive the wheel and die on the shelf. Round forms dry differently, trim differently and crack differently, and a closed one carries a job you cannot skip.

After the wheel, in order 0 of 8 ticked
After the wheel, in order 0 of 5 ticked

Round forms cost more to fire than they look like they should

Glaze firings here are five cents per cubic inch with a $4.80 minimum, measured at the widest points. That means a sphere is charged like the cube it would fit inside. A six inch ball is 6 x 6 x 6, so 216 cubic inches, so $10.80. A four inch ball works out at $3.20 and lands on the minimum instead, at $4.80.

Nothing sneaky is happening. A round pot really does occupy that whole box on a kiln shelf. It is just worth knowing before you make nine of them. Bisque firings stay free, every time. Run your own numbers on the calculators page.

What to actually do with one

Both of these go past the throwing and into the part where it becomes an object. The second one is the only good demonstration we found of trimming a round bottom in a chuck.

Little Street Pottery16 min “10 Tips on How to Throw Closed Form Pottery - With 3 Projects!” Ann answers the question everyone asks about ten seconds after their first successful sphere, which is what on earth do I do with a ball. Three finished projects, and the tips are the practical kind rather than the inspirational kind.
KaransPotsAndGlass8 min “Salt and Pepper Shakers- Throwing & Trimming an Enclosed Spherical Round Form on the Potter’s Wheel” The full arc in one sitting: thrown as something vase-shaped, closed, then turned upside down and trimmed round. If you have been wondering how a ball gets a rounded bottom without a flat spot, this is the answer.

09 · Diagnosis

07 · Diagnosis

It went wrong. Here is which one

Fourteen failures we watch happen, and the cause of each. Almost none of them are your hands. Find the symptom, read the cause, and change that one thing on the next attempt rather than changing everything at once.

The four that happen on the first night, and the cause of each. Almost none of them are your hands. Change that one thing on the next attempt rather than changing everything at once.

The neck wrinkled into pleats while I collared it Cause. Too much travel in one pass, or the wall where the collar landed was thinner or wetter than the rest. Fix. Pull the wall up once from the inside to stretch the pleats back out, compress the rim, then collar again taking about a third as much per pass.
The neck went off center and started spiraling Cause. Your hands were not a closed ring, or one hand led the other. Clay escapes through the gap once per rotation, and a spiral is what that looks like. Fix. Slow the wheel further, close the ring properly, and true it with even pressure over several full turns. If it is badly gone, cut the top off with a needle tool and start the neck lower down.
The rim went thick and floppy and will not behave Cause. Nothing has gone wrong. Shrinking a circle forces the same clay into a smaller circumference, so the rim thickens by definition. Fix. Compress it back to an even thickness between every single pass. If it has bunched up badly, level it off with a needle tool and lift the ring away.
The belly collapsed as soon as I pushed it out Cause. The wall was too thin, too wet, or you pushed high up before the section underneath had been formed. Fix. Belly from the bottom upward in continuous climbs, use noticeably less water, and ride a rib on the outside to catch the wall as it moves.
It came out egg-shaped rather than round Cause. The widest point ended up too high or too low, or you pushed one section out instead of climbing through the whole wall. Fix. Check the profile from the side after every pass, not from above. Work bottom to top in one slow travel, and stop the moment the curve reads right.
It looks like a ball sitting on a dinner plate Cause. The base is too wide. Nothing you do above the base can rescue this, which is why it is step one. Fix. Open a narrower floor next time, around a third of the finished width, and undercut the base with a wooden tool before you wire it off.
The pot got shorter and fatter every time I collared Cause. That is simply what collaring does. It is not a mistake, it is the trade. Fix. On an open form, pull the wall up once between collaring passes to win the height back. On a closed form, build the height in before you start closing, because you only get so many chances.
A crack appeared in the floor a week later Cause. The floor was not compressed enough. A sphere has a small floor, so every bit of drying stress that a wide base would spread out lands in one place instead. Fix. Compress the floor twice with your fingers and once more with a rib, before you ever pull a wall. There is no step after the wheel that fixes this one.
The closed form went soft and stopped holding its shape Cause. Either a pinhole is letting the air out, or the wall is simply saturated and out of pulls. Fix. Hunt for the hole, wet a fingertip and smooth it shut. If it is saturation instead, stop touching it, let it firm for ten minutes, and come back.
My closed form slowly deflated overnight Cause. Damp clay is slightly permeable, so a freshly sealed form does let air seep out as it stiffens. Mostly harmless. Fix. Nothing to do unless the wall has actually gone concave. Do not wrap it airtight and forget about it for a week, though: that is how a soft sphere becomes a soft pancake.
The seam where I closed it opened up in the bisque Cause. The closure was pressed together rather than welded together. Two surfaces touching is not a join. Fix. Smooth and compress the closure while it is still wet until you cannot find where it was, then check it again at leather hard and compress it a second time.
It cracked open in the kiln Cause. There was no vent hole, so expanding air and steam had nowhere to go. Fix. Pierce every sealed form, every time, before it is fired. Pick one spot you always use so it becomes a habit rather than a thing you remember. If you are not sure whether a piece is sealed, ask us before it goes on the shelf.
It went oval somewhere between the wheel and the shelf Cause. Picked up too early, and picked up by the sides. Fix. Throw on a bat and carry the bat. If you genuinely have to lift it, support it from underneath and never squeeze the widest point.
The glaze pooled into a thick ring around the bottom Cause. Gravity, plus a curve that funnels everything toward one small point. Round forms are the worst shape on earth for this. Fix. Go noticeably thinner across the bottom third, and put a glaze catcher under anything ambitious.

If it made it out of the kiln looking wrong

Sharp spots, glaze runs and pieces fused to a shelf are a separate problem with separate answers. Our page on fixing pottery after a firing covers what is rescuable and what is not.

10 · Honest expectations

What attempt one actually looks like

Every video on this page is a take where it went right. That is not a criticism of anyone, it is just what a video is. Here is roughly how it goes for the rest of us, based on watching a lot of members meet this form for the first time.

The first few

You lose them at the collar

The cylinder goes fine. Then the neck folds, or the wall gives up, or it drifts off center and you keep going anyway because stopping feels like quitting. The real job of these attempts is discovering how slow slow actually is, and no amount of reading gets you there.

Once they survive

You get lumpy spheres

They stand up. The widest point wanders, the base is wider than you meant, and the curve has a flat bit on one side. This is the stage where a rib stops being a suggestion and starts being the thing that makes the shape.

Later

You start aiming

You decide the size before you sit down, and you land near it. Closed forms hold their air. The collar stops being an event you brace for and turns into a thing your hands just do while you think about the profile.

Two things that speed all of this up

Throw several in a row. Six small spheres in one session teaches you more than six single attempts across six weeks, because the only variable you are testing is what you changed in the last ten minutes.

Have somebody watch one. Almost every sphere problem is visible from two feet away and invisible from where you are sitting. There are instructors on the floor during every class time at the studio. Friday nights and weekend open studio are unsupervised, so save the question for a class night.

11 · Vocabulary

Every word we just used

Pottery has a habit of using two words for one thing and one word for two things. This is the short version, so a search result or a video description stops being a guessing game.

Collaring Squeezing a spinning form inward to make a circle smaller. Also called choking, or necking in. Section 04 is entirely about this.
Bellying out Pushing the wall of a cylinder outward from the inside to create a curve. Costs height and buys width.
Open form Any pot with an opening you could get a finger into. On this page it means a round body with a collared neck.
Closed form Confusingly, two different things. Some potters mean a fully sealed pot. Others mean any pot with a narrow neck. Check which one a video means before you follow it.
Enclosed form The less ambiguous term for a pot that is genuinely sealed shut with air inside. Worth searching for by this name.
Shoulder The part of the curve where the wall stops going outward and starts turning back in. On a sphere it is where the collar begins.
Compression Pressing clay particles back together after a move that dragged them apart. Rims and floors need it most, and a sphere needs it more than a mug does.
Rib A flat tool of metal, wood or rubber used to shape and smooth. Once a form closes in, a rib on the outside is the only thing that still reaches the wall.
Chuck Anything that cradles a pot so you can trim a rounded base. A thrown clay collar, a bisque cup, a foam ring, or a padded bowl.
Undercutting Angling the base inward with a wooden tool before wiring off, so the pot appears to rest on a smaller point than it really does.
Weld Joining two clay surfaces so completely that the join stops existing. Pressing them together is not welding, and the kiln knows the difference.
Bat A removable disc that sits on the wheel head. Lets you take a soft round form off the wheel without touching it.
Leather hard Firm enough to handle and carve, still damp enough to join and trim. The window where a closed form gets pierced.
Vent hole The small hole you make in a sealed form before firing so expanding air and steam can escape. Not optional.

12 · Asked at wheel side

Questions we get about round forms

Do I need to be able to throw a decent cylinder first?

Yes, and there is no way around it. Every form on this page starts as a cylinder, and a wall that is thick at the bottom and thin at the top will hide that fact right up until the belly goes out and the thin part tears. If your cylinders still surprise you, spend a few sessions there first. Our full wheel guide covers all of it.

How much clay should I use for a first sphere?

One and a half to three pounds. Roughly a large orange up to a grapefruit. Small forms collar shut with far less drama, and you can throw six of them in the time one big attempt takes to fail.

Do I genuinely have to put a hole in a sealed piece?

Yes. Every time, no exceptions. Air expands when it gets hot and the water left in the clay turns to steam, and a sealed form gives both of them nowhere to go. One small pierce with a needle tool once the piece is firm is all it takes. If you are ever unsure whether something of yours is sealed, ask before it goes on the firing shelf.

Where should the vent hole go?

Wherever you will remember. Under the base is the usual answer because nobody looks there. Inside a carved pattern works if the piece has one. Some people make it obvious and turn it into part of the design. The only wrong answer is nowhere.

My closed form deflated. Have I ruined it?

Probably not. If it lost air slowly while stiffening, that is fairly normal and it only matters if the wall has gone concave. If it went soft under your hands on the wheel, you have a pinhole. Wet a fingertip, smooth it shut, and carry on. If you cannot find the leak, cut the top off and finish it as an open form.

Can I open a closed sphere later and turn it into a vase?

Yes. Wait until it is firm, then cut the opening with a needle tool and clean the edge. Do not do it while it is soft, because the moment you break the seal the air support disappears and the wall has to hold itself up again.

Can I glaze the inside of a closed form?

No, and you do not need to. There is no inside to reach and nothing is going to live in there. Concentrate on the outside, keep the glaze thinner across the bottom third because a curve funnels every drip to one small point, and stand it on a glaze catcher if you are trying anything that moves.

Which of our clays throws a sphere best?

Something with a bit of tooth. A bellied wall has to stand up while being pushed sideways, and grog or specks help it hold. Our #16 Porcelain is gorgeous and the least forgiving clay in the building, so it is a wonderful sphere number twenty and a rough sphere number one. All eight of our clay bodies are here.

Something we did not answer? The full studio FAQ page covers memberships, firings, glazes and the rest, or you can text the studio at 385-241-5528.

Go make a bad one

Nobody’s first sphere is round

Read the steps, watch one of the nine, then get a lump of clay on a wheel and lose a few. The list will still be here on your phone, and it does not mind being read with one clean knuckle.

Read the steps, watch the two clips, then get a lump of clay on a wheel and lose a few. The list will still be here on your phone, and it does not mind being read with one clean knuckle.

We have 29 wheels, four kilns and a room full of people who have all thrown a sphere that came out shaped like a pear. Bisque firings are free, so the practice costs you clay and nothing else.

One more thing worth doing tonight: throw several small ones in a row rather than one careful big one. Six in a session teaches you more than six attempts across six weeks.

Become a member Read the wheel guide

Want more from the potters above? We keep a whole page of hand-picked videos from ceramic artists who are not us. None of the nine on this page appear on that one, so between them you have a fairly deep afternoon.

There is a much longer version behind the Comprehensive toggle at the top: fourteen ways it goes wrong, all nine videos, a glossary and the questions we get at wheel side. We also keep a whole page of hand-picked videos from potters who are not us.