Hand Building

Turning a Paper Pattern into a Three-Dimensional Pot

A supplied pattern holds decisions somebody else made for their clay, their slab and their kiln. This lesson is about making those decisions yourself: a sketch at full size, a paper mockup you can change for the price of tape, a clay prototype that tells you what paper cannot, and a template you trust enough to use again.

Sketch it at full size, mock it up in card stock, scale it for shrinkage, build one in clay, measure it, and fix the template. Each stage is a cheaper test of the next one.

Sketch, paper, clay, template Seams, curves and bases Four videos, none of them ours

The route in eight steps The arithmetic on one screen Three things that go wrong

A potter compares her taped paper mockup with the faceted clay vase she built from it, paper pattern pieces still lying on a fresh slab

Jump to a section

Four stages, one loop Start with a full-size sketch What each form unrolls to Tapered walls and the fan Thickness and seams The paper mockup Planning the finished size The whole idea The route, in eight steps The arithmetic on one screen Curves paper cannot make Bases and feet The clay prototype Revise it, then make it last What goes wrong Three things that go wrong Questions we get asked Keep going

From a full-size sketch to a paper mockup, a clay prototype and a template you can use again.

The whole idea

Four stages, each a cheaper test of the next

A supplied pattern holds decisions somebody else made: the size, the slab thickness, the clay and how much it shrinks. Making your own means making those decisions, and testing each one in the cheapest material that can show it to you.

Paper tests the shape. A full-size sketch fixes the numbers, and a taped card stock model shows the proportions in the round for the price of tape. Clay tests the rest: a prototype shows the slump, the seams and the real fired size. The template keeps the answers, corrected, labeled and copied onto something that survives wet clay.

Every form you can sketch breaks into flat pieces. Straight walls are rectangles, tapered walls are fans, boxes and facets are flat panels. Only a shape that rounds two ways at once, like a belly, needs the clay to stretch.

What to actually do

From sketch to template, in eight steps

Draw it at full size. Set the height, widest point, opening and footprint, and mark each as an inside or an outside measurement. Draw half the side view against the fold of a folded sheet and cut it out to see the whole silhouette.
Break it into flat pieces. Each straight run of the side view is one piece: upright runs are rectangles, slanted runs are fans, and every corner is a seam. A curve that rounds two ways comes from a soft slab, darted, pushed out from inside, or draped on a slab mold.
Allow for the thickness. A cylinder wall is 3.14 times the diameter through the middle of the clay, plus half an inch to trim. Box walls that butt between the others lose two slab thicknesses, and walls standing on a base are cut one thickness short.
Mock it up in card stock at finished size. Tape the seams from outside, stand it up, use it and change it. Then take it apart along the seams: those pieces are your pattern.
Scale it for shrinkage. Divide every measurement by what is left after shrinking: at 12 percent, divide by 0.88, or print at 114 percent. Leave the slab thickness as you chose it.
Build one in clay. Same clay, thickness and stiffness you will always use: soft for curves, firm for flat panels. Score, slip, press and coil every seam, the base included, and scratch two marks 4 inches apart under the base.
Measure it after the final firing. Compare the pot with the drawing, and the marks with 4 inches. That is your real shrinkage.
Fix the template and make it last. Correct the finished-size master one change at a time, label it with clay, thickness and shrinkage, and trace it onto tar paper or laminated card stock.

The method

Four stages, each one a cheaper test of the next

Every stage exists to catch a mistake before it costs more to fix. Paper costs minutes. Clay costs an evening, the drying and a firing. A template that has been through both costs nothing to use again.

A supplied pattern is somebody else's decisions. The size, the slab thickness, the clay it was meant for, how much that clay shrinks, where the seams go. It works when those happen to match yours. Designing your own means making each of those decisions on purpose.
The sketch fixes the numbers. Height, widest point, opening and footprint, drawn at full size. Everything after it is measured off that drawing, so the drawing is where the design actually lives.
Paper tests the shape. A taped card stock model shows proportion, balance and how the pieces meet, in the round and at real size. Changing it costs a sheet of paper and a strip of tape.
Clay tests what paper cannot. Weight, slump, how a seam behaves while it dries, how far a soft wall leans, and the size the piece really comes out after firing. A prototype is a question, not a finished pot.
The template keeps the answers. Corrected from the prototype, labeled with the clay, thickness and shrinkage it was sized for, and copied onto something wet clay cannot ruin.
It is a loop, not a line. A prototype that sends you back to the paper is the method working. Often the second pass round the loop is where a design stops being a guess.

The sentence worth keeping

Make every mistake in the cheapest material that can show it to you.

Stage one

Start with a sketch at full size

Draw the pot the size it will be when it is finished. A thumbnail hides every proportion problem a full-size drawing shows you.

Start with the job. What it holds, how it is held, and where it lives. A vase for one long stem, a planter for a 4 inch nursery pot and a box for a deck of cards are three different sets of numbers before they are three different shapes.
Set the four numbers. Height, the widest point, the opening and the footprint. Write beside each one whether it is an inside or an outside measurement. An inside number is set by what goes in the piece; an outside number by the hand, the shelf or the table it lives on.
Draw half the profile against a fold. Fold a large sheet down the middle, draw half of the side view against the fold, and cut along your line. Opened out, it is a perfectly symmetrical silhouette at full size.
Hold the silhouette up. Against a wall, beside the thing it will hold, in your hand. Trim it and cut another until it looks right. It is the fastest proportion test there is, and it costs one sheet.
Read the profile as straight runs and corners. Every straight run in the side view becomes one flat piece of clay: upright runs are cylinders, slanted runs are cones, and every corner where the line changes direction is a seam. A curved line has to become either several short runs or a soft slab shaped after it is assembled.
Mark the seams on the drawing. Corners first, then anywhere a run is too long to cut from one slab. That marked drawing is the plan every piece is cut from.

Proportion, briefly

Thirds usually beat halves: a widest point a third of the way up or down reads as intended, and one exactly halfway reads as undecided. A footprint between a third and a half of the widest width tends to look right. How to Design Better Pottery goes through all of it. The silhouette in your hand is where you test it.

Flat into round

Six forms, and the flat shape each one comes from

Paper bends in one direction at a time. Anything it can wrap without wrinkling, a cylinder, a cone or a flat panel, unrolls into a flat shape exactly. Anything that rounds two ways at once, like a ball, cannot be flattened without stretching, and that is the one place clay does better than paper.

A straight cylinder: a rectangle

As tall as the wall, and as long as the distance around the middle of the wall, plus a little to trim. Mugs, tumblers, straight vases, pencil cups.

A tapered wall: a fan

Part of a ring, with the wide end of the pot on the long arc and the narrow end on the short one. Every flared cup and every tapering vase. The next section is about this one.

A box: one panel per side

Rectangles, or trapezoids if the walls lean. Straight sides want firm slabs, so these pieces are cut at leather hard and put together more like carpentry than sculpture.

A faceted form: triangles and trapezoids

Every face is flat, so paper models it perfectly and the clay version can look exactly like the paper one. The vase at the top of this page is two rings of facets, one widening and one narrowing.

A stacked form: bands

A base that flares, a straight body and a shoulder that turns in are three bands: a fan, a rectangle and another fan, seamed where the profile changes direction.

A belly or a dome: no flat shape

Round in two directions at once, so no flat pattern makes it on its own. Darts, pushing the wall out from inside, or a slab mold does that work, and the section on curves covers all three.

Five minutes that teach the fan

Cut a ring out of paper, take a slice out of it, and tape the cut ends together: it stands up as a cone with its top cut off. Take a bigger slice and the cone gets steeper. A few of those teach the shape better than any formula.

The shape people get wrong

A tapered wall is cut as a fan, never a trapezoid

The two ends of a tapered wall are different sizes, so laid flat, both edges become arcs around one shared center. Cut them straight and the rim will not sit level.

Why it curves. A cup 4 inches across at the rim and 2½ at the base has a rim about 12½ inches around and a base just under 8. Laid flat, those two edges are arcs of two circles drawn from the same point: the point the cup's sides would meet if they kept going.
What a trapezoid does instead. Wrap a shape with straight top and bottom edges into a cone and both edges come out uneven, rising or dipping opposite the seam, and the base rocks. You can trim the rim level, but you are cutting away height you designed.
Way one: roll it in paper. Curl a sheet of card stock into the cone you want, around your mockup or a cup that already has the right taper, and tape it. Stand it on the table, mark the rim height all the way around with a pencil resting on a stack of books, cut along the mark, then slit it down one side and unroll it. No arithmetic at all.
Way two: draw it from the profile. On your full-size side view, extend the two slanted sides until they meet. That meeting point is the center. Tie a pencil to a string, hold the string at the center, and swing one arc through the base corner and one through the rim corner. Mark off the long arc to the distance around the wide end, and draw a straight line from each end of it back to the center.
Way three: let a generator draw it. The free truncated cone template at templatemaker.nl takes a top diameter, a bottom diameter and a height in inches and prints the fan to scale, across several sheets when it is big. Set the glue flap to zero, print at 100 percent and tape the sheets together. A Ceramics Monthly article on tar paper templates uses exactly this route.
A gentle taper puts the center a long way off. The closer the two ends are in size, the farther away the center of the arcs sits: a wall that tapers by half an inch can put it several feet off the drawing. Tape on more paper, or use way one or way three.
The straight sides are the seam. The two straight edges of the fan meet when it closes. In clay, bevel both of them, sloping opposite ways, exactly as you would the ends of a cylinder.

Measure the fan through the middle of the wall

The diameters that set the fan are the ones through the middle of the clay, not the inside or the outside. The next section explains why, and the arithmetic section has the formula with a worked example.

Where patterns fail

Thickness, seams and the measurements that go wrong

Paper has no thickness. A 3/8 inch slab does, and every measurement on a clay pattern has to account for it.

Measure through the middle of the wall. When a slab wraps into a cylinder, its outside face stretches and its inside face squeezes, and the line through the middle stays the length you cut. So the wall is 3.14 times the diameter through the middle of the clay, plus half an inch to trim. Our slab mug lesson works this through for a former and does the arithmetic for you.
Decide inside or outside, every time. A box for a deck of cards is set by its inside. A box that has to fit a shelf is set by its outside. Mixing the two on one drawing is the quickest way to a piece that comes out a wall thickness off.
Butt joints change the length of two walls. In a box with butt joints, two opposite walls run the full outside length, and the two that fit between them are shorter by two wall thicknesses. With 3/8 inch slabs, that is three quarters of an inch.
Beveled corners keep every panel at its outside size. Cut each meeting edge at 45 degrees and all four walls of a box are cut to the outside measurement, with the seam landing right on the corner. Where a corner turns less than a square one, the bevel is half of the turn: a six-sided form turns 60 degrees at each corner, so each edge is cut at about 30.
The base changes the height. Walls that stand on top of a base slab finish one slab thickness taller than the walls themselves. Cut them that much shorter, or the pot comes out tall by exactly that.
Put seams where nobody looks. On a corner, at the back, under a handle, along a facet line. Keep them out of the places that take strain, like the tightest part of a curve or the middle of a long flat wall.
Letter the seams. Draw a short tick across every seam line on the template and a matching letter on both sides of it: A meets A, B meets B. Scratch them onto the slab when you trace, and the pieces go together the way you designed them instead of mirrored.
Cut long, trim to fit. Add a little to every seam edge and every rim, and trim once the piece is assembled. A wall that comes out short cannot be stretched back; one that comes out long takes a minute to fix.

The rule underneath all of it

Every join is the same clay body at the same wetness, scored, slipped and pressed, with a thin coil in the inside corner. How to Score and Slip a Join is the long version. No template's accuracy survives a join that opens.

Stage two

The paper mockup: tape it, stand it up, judge it

Build it at the size it will be when it is finished, out of something stiff enough to stand. This is where changing your mind is cheapest.

Making paper templates for a stiff slab vessel Mission Hills Ceramic Arts Thirteen minutes of drawing paper templates, cutting them out and taping them into a model of a stiff slab vessel. This stage, start to finish.

Use card stock or tagboard. Printer paper is fine for drawing a pattern, but it folds under its own weight once it has to stand. Thick paper holds a wall up the way a firm slab will.
Build it at finished size. You are judging the object you will live with: how it sits in a hand, what fits inside, how it looks on the shelf. The scale-up for shrinkage comes after the design is settled.
Tape the seams from the outside. Edges meet edge to edge; paper needs no bevel. Two or three pieces of tape across each seam are enough to judge it, and easy to pull off again.
Look at it from across the room. Then squint, or photograph it from the side and darken the picture until it is a silhouette. The outline is most of what anyone sees of a pot.
Use it. Hold it the way you will hold the pot. Put the stems, the plant pot or the cards in it. Set it where it is going to live.
Change it now. Too tall: trim the band and tape it again. Too narrow at the base: redraw that piece. Every change here costs minutes. The same change in clay costs a slab, the drying and a firing.
Take it apart along the seams. Flattened out, those pieces are the pattern at finished size. Keep them, write on them, and do not cut clay from them yet.

What paper cannot show you

Weight. How a soft wall sags before it firms. Whether a seam stays closed while it dries. How much the piece shrinks. Paper agrees with everything; the prototype is where the clay gets its say.

Finished dimensions

Plan the finished size, then cut bigger on purpose

Our clays lose roughly a tenth to a seventh of their size between the wet slab and the finished pot. The pattern you cut clay from has to be that much bigger than the mockup.

Divide, do not add. The size to cut is the finished size divided by what is left after shrinking. At 12 percent shrinkage that is the finished size divided by 0.88, so a 6 inch pot is cut at about 6.82 inches. Adding 12 percent instead gives 6.72, which comes out short, and the gap grows with the piece.
Scale every measurement by the same amount. Height, widths, the length of every piece and both radii of a fan all grow together. A fan's angle does not change when it is scaled, so a scaled fan still closes into the same shape.
A copier or a printer does it in one step. Shrinkage of 12 percent means printing the pattern at 114 percent. The table in the next section has the setting for each shrinkage our clays come in.
Do not scale the slab thickness. Thickness is a working decision you make wet, the way our slab lessons give it. It shrinks along with everything else.
Use your clay's number, and know it is an average. The makers of our clays publish shrinkage from 10 percent for 52 Buff to close to 14 percent for #16 Porcelain, with most of them around 12. Those figures come from test bars, and our calculators page calls them what they are: the makers' averages.
A rolled slab shrinks a little more one way. Rolling lines up the clay's flat particles in the direction the slab traveled, so it shrinks more along that direction than across it. A quarter turn between passes evens that out, and our slab roller tips explain why.
Inside numbers need the walls added back. When the inside has to clear something, a nursery pot or a jar, design the inside first, add both walls to get the outside, and scale that.

Measure your own number on the prototype

Scratch two marks exactly 4 inches apart on the wet slab, somewhere they will not show, such as under the base. After the final firing, measure between them again. If they are 3½ inches apart, your clay shrank 12½ percent with your slab and your drying, and that is the number to use next time. A bisqued piece has not finished shrinking.

Keep this open at the table

The arithmetic, on one screen

Every number a template needs, in one place. Measure every diameter through the middle of the wall, and work in wet sizes once the design is settled.

Your clay shrinks	Print or scale the pattern at	A 6 inch finished height is cut at	Clays we stock near it
10 percent	111 percent	6.67 inches	52 Buff
11 percent	112 percent	6.74 inches	B-Mix w/Grog
12 percent	114 percent	6.82 inches	B-Mix, Speckled Buff, Half & Half, Berlin Gray
12½ percent	114 percent	6.86 inches	B-Mix w/Specks
14 percent	116 percent	6.98 inches	#16 Porcelain

The piece	How to size it	Worked example, 3/8 inch slab
Any measurement	Wet size = finished size divided by (1 minus the shrinkage).	6 inches at 12 percent: 6 divided by 0.88 = 6.82 inches.
Cylinder wall	Length = 3.14 × the diameter through the middle of the wall, plus 1/2 inch to trim.	4 inches across the outside: 3.14 × 3 5/8 = 11 3/8, so cut it 11 7/8 inches long.
Box, butt joints	Two walls at the full outside length. Two walls at the outside width minus two slab thicknesses.	A 6 by 4 inch box: two walls at 6 inches, two at 3¼.
Box, beveled corners	All four walls at the outside size, every corner edge cut at 45 degrees.	Two walls at 6 inches, two at 4.
Walls on a base	Wall height = finished height minus one slab thickness.	5 inches tall overall: walls 4 5/8 inches.
Fan for a tapered wall	Big radius = slant length × wide diameter, divided by (wide minus narrow diameter). Small radius = big radius minus slant length. Angle in degrees = 180 × wide diameter, divided by big radius.	4 and 2½ inches across, sides 4½ inches long: radii 12 and 7½ inches, angle 60 degrees, a sixth of a ring.

Or let it draw the fan for you

The free truncated cone template at templatemaker.nl draws the fan from a top diameter, a bottom diameter and a height. Enter the wet sizes, measured through the middle of the wall, set the glue flap to zero and print at 100 percent.

How to Make a Template for a Conical Slab Mug The Pottery Wheel Twenty-one minutes on three simple ways to make the template for a conical mug, which is the fan worked through at the table.

Round two ways at once

Curves the paper cannot make, and how clay makes them

Paper bends one way at a time. A soft slab can stretch a little, and that small difference is how a flat pattern becomes a belly, a dome or a wall that swells.

Soft slabs for curves, firm slabs for flat panels. A soft slab bends and stretches; a firm one stands up straight and cuts clean. A slab asked to curve after it has gone leather hard cracks along the outside of the bend. Our leather hard lesson covers both ends of that window.
Darts pull a flat edge into a curve. Cut a narrow V from the edge of the slab and close it, scored and slipped, and the edge gets shorter there and the slab cups. Several small darts spaced evenly around an edge draw it in evenly, which is how a soft slab cup gets a rounded base or a narrower rim. One big dart makes a point instead of a curve.
On paper, darts crease. Draw the darts on the paper pattern and close them with tape to see roughly where the form goes. The paper folds at each dart where the clay will round, so judge the size from it, not the smoothness.
Push it out from inside. Once the seams of a soft slab form are closed, reach in and press the wall outward with a rib or your hand while the other hand supports the outside. That is how a straight paper pattern becomes a belly. How far it will go is something only the prototype tells you.
Let a slab mold do it. Draped over or pressed into one of our slab molds, a soft slab takes a curve no flat pattern could give it, and the template only has to cut a piece big enough to cover the mold. How to Use Slab Molds walks through it, and the slab rollers and slab molds need the free certification first.
Or build the curve out of facets. A ring of flat panels follows a curve in steps, models exactly in paper, and is built from firm slabs. The vase at the top of this page does exactly that.

Write the curve on the template

Wherever the prototype was darted, pushed out or draped, note it on the template: where, how far, and how stiff the slab was. That note is the part of the pattern no tracing can carry.

What it stands on

Bases and feet

Cut the base from the same slab as the walls, so it is the same thickness and dries at the same speed. How it meets the walls is a choice, and each choice suits a different form.

Walls on top of the base. The usual route. Cut the base a little bigger than the footprint, stand the walls on it, and trim the extra flush once they are joined. This is the one that changes the wall height by a slab thickness.
Trace the walls instead of measuring them. For anything round, oval or irregular, build the walls first, stand them on the base slab and trace around the outside with a needle tool. Cut a little outside the line. No arithmetic, and it always fits.
Fold the base up the outside. Cut the base about half an inch bigger all round, set the walls on it, and fold that extra up onto the outside of the wall. A Pottery Making Illustrated article uses this on soft slab vessels so the bottom does not crack where it meets the sides.
A coil in the inside corner, every time. Thin, pressed in and blended into both the floor and the wall. It is the strength in that joint you will never see.
Dry the floor at the speed of the walls. An S shaped crack across a floor comes from the floor and the walls shrinking unequally, usually a floor still wet while the walls have dried. Ribbing the base slab on both sides helps, but it is not the cure. Cover the walls so they do not race ahead, and turn the piece upside down as soon as it is firm enough to handle, so the floor gets air too.
Feet go on later, from their own small template. A ring or a set of feet is added at leather hard, cut from a strip or a small pattern of its own. A footprint between a third and a half of the widest width tends to look right; narrower lifts the form and tips more easily. Our feet and foot rings lesson covers attaching them.

Stage three

The clay prototype: build it to learn something

Build the first one exactly the way you mean to build every one after it: same clay, same slab thickness, same stiffness. Then watch it, because it shows you everything the paper could not.

How to use templates for pottery handbuilding Lisa Reeve - Cabin Ceramics Pottery Eighteen minutes: a set of templates, how they are made, and a vase built from one.

Scale the pattern and cut it out. At the size your clay's shrinkage calls for, with every seam lettered and every bevel marked.
Roll the slab and let it reach the right stiffness. Soft for wrapping and curving, firm for flat panels. Roll it on a slab roller once you are certified, or by hand with guide sticks.
Lay the pattern on and trace it. Mark around it with a needle tool, or press its edges lightly into the slab and cut along the line they leave. Lift the paper straight off rather than sliding it. Cut upright for butt edges and at the bevel for the rest.
Scratch the shrinkage marks. Two marks exactly 4 inches apart, under the base.
Assemble it in order, and note what fought you. Every join scored, slipped, pressed and coiled. Write down where a seam would not close, where a wall sagged, and how much you trimmed.
Measure it three times. Wet, as soon as it is assembled. Bone dry. After the final firing. Compare each one with the drawing.
Change one thing for the next one. Change two and you learn that something happened, not which change did it. Three Tries, One Change sets that up properly.

What to look for

Whether it slumped or leaned out while it was soft. Whether any seam opened as it dried. Whether the rim sits level and the floor stayed flat and whole. Whether it is the size you drew. Then use it for a while, the way it is meant to be used, and notice what you would change.

Stage four

Revise the template, then make one that lasts

Correct the paper from what the prototype taught you, write down what it was sized for, and copy it onto something wet clay cannot ruin.

"Teacher Toolbox" Making durable slab building templates Huebner Pottery Five minutes on making slab building templates that last, built for a bowl project.

Correct the master, not a copy. Mark every change on the finished-size pattern first: how much taller, which seam moved, where the darts go. Then redraw it clean and scale it again. The finished-size master is the design; the scaled copy is the tool.
Write on it. A template with no notes is a supplied pattern again, just one you happened to make. The list below is what belongs on every one.
Card stock and tagboard are fine for repeated tracing, and laminated paper lasts longer still. All of them soften if they sit on a wet slab, so trace and lift.
Tar paper survives the wet. Sold as roofing felt at most hardware stores, it is tough, flexible enough to curve, and waterproof. Trace the paper master onto it and cut it out with a utility knife.
Keep it flat, with its notes. A folder or a large envelope holding the master, the working copy, the prototype's measurements and a photo of the pot it made.
Make a new version, not a new pattern. When you change it again, number it as the next version and keep the old one. The first time a change makes things worse, the old version is how you get back.

On every template

The piece, and its version number
The clay body it was sized for, and that clay's shrinkage
The wet slab thickness
Soft or firm when it was cut
Which edges are beveled, and which way
A letter on both sides of every seam
Where to dart, push out or drape
The date, and the fired size it produced

Reading a prototype

What goes wrong, and what it means

It came out small

The pattern was cut at finished size, or it was scaled by adding the shrinkage instead of dividing it out. Scale the master again from the finished drawing, at your clay's number.

The seam would not close

The length was measured on the inside of the wall, or nothing was left to trim. Measure through the middle of the wall and cut half an inch long.

The rim is not level

A tapered wall was cut as a trapezoid, or the fan's two arcs were drawn from different centers. Redraw the fan from one center, and leave a little height to trim.

The walls sagged or leaned out

The slab was too soft for a standing wall, or a tall piece had nothing holding it while it firmed. Flat panels want firm slabs; curves want soft ones.

A seam opened as it dried

Two pieces at different wetness, a butt joint asked to follow a curve, or no coil inside. Match the stiffness, bevel the seam and coil every inside corner.

The floor cracked

An S shaped crack is a floor and walls that shrank unequally, usually a floor still wet while the walls dried. Cover the walls, and turn the piece upside down as soon as it can take it, so the floor dries too.

Worth knowing first

Three things that go wrong

It came out small

The pattern was cut at finished size, or the shrinkage was added instead of divided out. At 12 percent, 6 inches finished is cut at 6.82 inches, not 6.72.

The seam would not close

The length was measured on the inside of the wall. Measure through the middle of the clay, cut half an inch long and trim to fit.

The walls slumped, or cracked at the bend

The wrong stiffness for the build. Curves want a soft slab that bends; flat standing panels want a firm one that holds itself up.

Questions we get asked

The ones that come up at the tables

Can I just use a template I found online?

Of course, and plenty of them are good. Treat it the way this lesson treats your own: build it in paper first and check its size against what you want. A downloaded pattern was sized for somebody else's clay, slab thickness and shrinkage, and it may not say which.

Do I need to be good at math?

No. Rolling card stock into the shape you want and cutting it open needs no numbers at all, and the free generator draws a fan for you. The arithmetic on this page is there for checking a pattern, not as a gate in front of it.

How thick should my slabs be?

Our mug and box lessons work at 3/8 inch, and a big slab mold piece wants about half an inch. Thicker for taller and larger walls, thinner for small and delicate ones. Whatever you choose, choose it wet and write it on the template.

Why is my mockup a different size from my template?

Because they do different jobs. The mockup is the pot you will end up with, so it is finished size. The template is what you cut wet clay with, so it is bigger by your clay's shrinkage.

How do I make a template from a pot I already own?

For a straight or tapered pot, wrap card stock around it, tape it, trim it level at the rim and the base, and cut it open down one side. For a faceted or boxy pot, trace each face. Either way you have its finished size, so scale it up before you cut clay.

Can one template make different sizes?

Yes. Print it at a larger or smaller scale and every piece changes together, and a fan keeps its angle. Thickness does not scale with it, so a much smaller version may want a thinner slab, and that is worth a prototype of its own.

Where should the seam go on a cylinder?

At the back, or where a handle will cover it. A beveled seam closed properly is hard to find, but the back is still the place for it.

Why did my prototype go oval?

Often the slab. Rolled through the same way every pass, it shrinks more in one direction than the other, so turn it a quarter turn between passes. Squeezing the form while you join it, or taking it off its former too early, does the same thing.

Keep going

Where to go next

How to Make a Slab Mug

The cylinder from start to finish, with a calculator for the wall length that allows for your clay's shrinkage.

Read it →

How to Score and Slip a Join

Every seam on a template depends on it: what happens inside a join, the method in order, and why joins fail.

Read it →

Leather Hard Clay: Soft and Hard

Soft slabs for curves, firm slabs for boxes, and how to tell which end of the window you are at.

Read it →

How to Design Better Pottery

Silhouette, proportion, weight and balance: the eye behind the sketch.

Read it →

Three Tries, One Change

How to set up each try so it answers one question instead of adding to the confusion.

Read it →

Lidded Boxes and Treasure Boxes

A box from paper templates, built closed and cut open, with every seam coiled.

Read it →

One last thing

The pattern is yours now

A supplied pattern is a set of answers. Designing your own is knowing the questions: what the piece is for, which numbers are inside and which are outside, how thick, how soft, how much it shrinks, and where the seams go. Once you can ask them, any pot you can sketch is a pot you can build.

Start with something simple, a tapered cup or a five-sided box, and take it all the way round the loop once. Then bring the next idea to the studio as paper, and build it in clay with us.

Sketch it at full size, mock it up in card stock, scale it by your clay's shrinkage, measure every diameter through the middle of the wall, build one in clay, measure it, and fix the template. Then copy it onto something that lasts.

For the reasons behind each step, the fan drawn three ways, curves, bases and what each failure means, switch to the Comprehensive Version at the top of the page.

Mon	Class 10:30 AM to 2 PM · Class 6:30 to 10 PM
Tue to Thu	Class 6:30 to 10 PM
Fri	Open studio 6:30 to 10 PM
Sat to Sun	Open studio 10 AM to 1:30 PM

Mon	Class 10:30 AM to 2 PM · Class 6:30 to 10 PM
Tue to Thu	Class 6:30 to 10 PM
Fri	Open studio 6:30 to 10 PM
Sat to Sun	Open studio 10 AM to 1:30 PM

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