Surface and decoration · Using mason stains

One jar of powder colors clay, slip, engobe or glaze.

A stain is color that has already been fired, so it does the same thing every time, although the powder looks different from the fired color. The percentage changes for each thing it goes into, the note on the jar decides which glaze it survives in, and a test tile decides everything else.

Four steps with a tick list at each: the four uses and their percentages, weighing and wetting, wedging or sieving until it is even, and the test tile. Six fixes, six videos, and the safety rule that opens every jar.

This is the short version: the four percentages, the mask, the paste, the sieve and the tile, each with a tick list. The chemistry, the food-safety notes and the questions are in the comprehensive version.

x4Uses. Body, slip, glaze, wash, each with its own percentage
MaskOn, every time the jar is open
x6Videos, from six channels that are not ours
x4Steps, each with a tick list you can work off
Jump to a section
Why this page has words and video The whole idea in a few lines The technique in six moves What you need on the bench 1. Four uses, four percentages 2. Mask, weigh, wet 3. Wedge or sieve 4. The tile Six potters, four uses The one video to watch When it goes wrong How it works at The Clay Hole Questions people actually ask Related lessons
Illustration of a bearded potter in glasses and an apron stirring green stain into a bowl at a wooden bench, with jars and small piles of colored stain powder, a brush and a test tile in front of him.

Every use in full, the chemistry, the safety notes and six videos.

Read it, then watch it

Why this is written down and filmed, both.

Stains are a table of percentages with a compatibility note attached, and tables are what a page is for. Five to ten in clay, five to fifteen in slip, two to ten in glaze, a wash at half stain and half flux. Nobody remembers those from a video. What a page cannot show is a paste being wedged into clay until the streaks vanish, or a sieve being worked, and those are the videos. Six of them, because stains have four uses and a compatibility note that catches people out.

Use both, in this order

Read the percentages and the compatibility note for your color. Watch the use you want. Mix a test tile before a pot, every time, with the tick list open.

The whole idea

One jar of fired pigment, four percentages, one test tile.

A stain is color that has already been fired, so it is predictable, although the powder looks different from the fired color. Five to ten percent colors a clay body, five to fifteen a slip or engobe, two to ten a glaze, half stain and half flux, thinned with water, makes a wash. Wet the powder first, sieve or wedge it in, read the note on the jar, fire a tile before a pot. Mask on whenever the jar is open.

The five-minute version

The whole technique in six moves.

If you already mix slips or glazes and you just want the shape of it, this is the shape of it. Everything below is these six moves, slowed down and with the places they fail marked.

1Pick the use, then the percentageClay body five to ten. Slip or engobe five to fifteen. Glaze two to ten. Wash: half stain, half flux, then water.
2Read the note on the jarChrome-tin pinks need calcium and die with zinc. Encapsulated reds fade if overfired. The chart says which base.
3Mask on, weigh by dry weightPowder is fine ground metal. Weigh over a damp towel, away from shared tables.
4Wet it to a paste firstDry stain clumps. About its own weight in water, a paste, then into the clay, slip or glaze.
5Wedge or sieve until it is evenClay: wedge far more than feels right, cut it to check. Slip: 80 mesh sieve. Glaze: 80 mesh sieve, twice.
6Fire a tile at cone 5½Color and fit, under the glaze you mean to use. Then the pot.

Before you open the jar

What you need on the bench.

Six things, and the respirator is not optional. The sieve is the one people skip and then wonder about the speckles.

A jar of stainWe sell them by the 25 grams. One unit colors about a pound of clay in the middle of the range, and strong colors go further. Buy the colors in the middle of the chart first: a blue, a green, a warm brown, a black.
A scaleEverything is by dry weight, and one percent is the difference between a tint and a color.
A fitted respirator, and glovesAn N95 is the minimum, and a half mask with P100 filters is the right tool for weighing and mixing powder. Cloth and paper dust masks do not count. Every time the jar is open.
An 80 mesh sieveFor slip, engobe, glaze and wash. Uneven color is unsieved stain nearly every time.
Soft clay, or slip, or a base glazeClay from our shelves. Nothing ever goes into one of our glaze jars, so a stained glaze means one you mixed yourself, and that needs a word with the studio team before it is fired. A stain colors whatever it goes into; the base decides the fit.
Test tilesOne per color per base, fired at cone 5½ before any pot. Write the percentage on the back.

A jar of stain, a scale, a fitted respirator and gloves, an 80 mesh sieve, the clay, slip or glaze it is going into, and test tiles.

1

Step one

Decide what the stain is going into, and read the note on the jar.

One powder, four jobs, four percentages. Into a clay body it colors the clay through. Into a slip or an engobe it colors a coating. Into a glaze it colors the glass. With water it is a wash for wiping into texture. The percentage is different for each.

5 to 10 percent

Clay body

Of the dry clay weight, up to fifteen for weak colors. The color runs through the pot, shows on every trimmed edge and every carved line, and cannot wear off, because it is in the clay and not on it. Past fifteen the clay goes short and cracks. Strong stains, cobalt blues and blacks, want the low end.

5 to 15 percent

Slip and engobe

Of the dry weight of the slip. The cheapest way to a whole range of colors from one bucket of slip and a few jars, and the way to match a color to your own clay body. A bottled underglaze is the same idea with much less clay and much more pigment, plus a binder so it brushes well. Our engobes lesson is the coating side.

2 to 10 percent

Glaze

Of the dry glaze weight, most colors between two and six. Stain stiffens a glaze, so the top of the range changes the fit. The base glaze has to suit the stain: read the compatibility note first.

Half and half

Wash

Equal parts stain and a flux such as a frit by dry weight, thinned with water until it looks like watercolor, about two and a half times the dry weight in milliliters. Brushed on and wiped back so only the texture keeps it. A clear over the top on anything that touches food. Our wipe-away lesson is the method.

Then the note on the jar, which is the part beginners skip and regret. Chrome-tin pinks and maroons need calcium in the glaze and die with zinc. Some blues and greens are happy anywhere. Encapsulated reds, oranges and yellows fade if fired past their limit. The supplier’s chart lists a compatibility note for every color, and a stain in the wrong base fires out to gray.

Tick list, choosing0 of 4
2

Step two

Mask on. Weigh it dry, then wet it to a paste.

The jar does not open without a mask. Stain is ground metal oxide that has been fired until the metals and minerals react into a crystal, then ground again, safer than raw oxide and still not for lungs. A fitted respirator (an N95 at the very least, a half mask with P100 filters for mixing powder), gloves, a damp towel under the scale, never at a shared table.

Weigh by dry weight. For clay, that means the dry weight of the clay, which for soft clay from the bag is roughly three quarters of what the scale says; for a pound of soft clay, about a twelve ounce dry weight, so ten percent is a little over an ounce of stain. For slip and glaze, weigh the dry materials before the water goes in, or work from the recipe. Write the numbers down; you will want to repeat the good one.

Then wet it. About its own weight in water, stirred into the weighed powder until it is a smooth paste with no dry pockets. Dry stain dropped into wet clay or slip clumps, and every clump is a speck on the pot. The paste is the whole difference between an even color and a marbled one.

Tick list, weighing0 of 4
3

Step three

Mix it in until it is even. Wedge, or sieve.

Stain does not dissolve. It has to be spread. Into clay: spread the paste on softened clay, fold it in, wedge far longer than feels necessary, then cut the lump in half and look. Streaks mean more wedging. Into slip, engobe or glaze: stir the paste in, then sieve through 80 mesh, glaze twice.

A marbled lump is not a failure if you wanted marbled clay, and some potters stop wedging on purpose at the streaky stage. For an even body, keep going. Stained clay is also a good candidate for a second wedge the next day, after it has rested and evened out its moisture. Our wedging lesson is the method.

Keep stained clay separate from everything: its own bag, its own name, and never the studio reclaim. A scrap of cobalt-stained clay in the studio reclaim is a blue speck in somebody else’s bowl months later. Stained slip and glaze go in labeled containers with the percentage and the base written on the lid.

Tick list, mixing0 of 4
4

Step four

Fire a tile before a pot. Then use it.

The tile is the recipe. One test tile per color per base, fired at cone 5½ under the glaze you mean to use, with the percentage and the base written on the back in underglaze. A stained body wants a tile with a carved line and a clear over half of it. A stained slip wants a tile of your clay with the slip on it. A stained glaze wants the glaze on the clay it will live on.

Then use it the way the tile told you. A stained body throws, hand-builds and trims like the clay it came from and shows its color on every cut edge, which is why potters carve it. A stained slip or engobe goes on leather hard for a surface that fires like clay, or bisque for engobe, and takes sgraffito beautifully. A stained glaze is a glaze, with the fit the tile showed. A wash wipes into texture and wants a clear over it on anything that touches food.

Food safety follows the glaze, not the stain: a stained body or a wash under a clear glaze that the Food Safe Lookup clears for food is as safe as that glaze, so check the clear you pick there. Bare stained clay or a bare wash does not go on a food surface. The reds, oranges and the Mango that hold cadmium inside a zircon shell stay off food surfaces unless the finished piece has been tested. When in doubt, a coat of clear, which is the answer to most glaze questions.

Tick list, the tile0 of 4

Watch it done

Now watch six videos on using one jar four ways.

Watch this one, then go read the note on the jar.

None of these videos are ours. Between them they cover what a stain is against an oxide, stain into clay twice, stain as a wash, stained slip against bought underglaze, and what a stain is and what it colors. Nothing but the still frame loads until you press play.

Seventeen minutes on glazing with oxides and stains, starting with how the two differ. The other five videos are in the comprehensive version.

Start here: oxides against stains #4 Glazing - Oxides and Stains Potters Sculptors
Seventeen minutes on glazing with oxides and stains. The chapters open with an introduction to materials, then oxides against stains, mixing and preparing, wiping oxide into texture, a stain demonstration, highlighting carved lines and painting on glaze. Watch on YouTube
Stain into clay, start to finish How to MAKE COLORED CLAY!!! The ENTIRE PROCESS! Jonthepotter
Twelve minutes on making colored clay. The chapters are preparing to mix the pigments, mixing and wedging the colors, making marbled patterns and throwing the clay on the wheel. Watch on YouTube
The five-minute version How to Add Colors to Clay using Mason Stains | Ceramics Ceramic Jim
Under five minutes on adding mason stains to clay. The description says three stains are tested at different amounts, and the chapters cover calculating the ratios, mixing and shaping tiles, and the fired results. Watch on YouTube
Stain as a wash How to use Mason Stains: Making a Wash (Bonus: Making Oxide Washes) YAS ClayCommunity
Three minutes on making washes from a mason stain and from oxides. The description gives two recipes, each a colorant with Gerstley borate (4 to 1 for the green stain, 1 to 1 for the yellow ochre), and the video shows a wash brushed onto a pot. Watch on YouTube
Stain in slip, against underglaze Underglaze VS Making colored slips with stain? FREE pdf with 44 recipes! Nu Kua Ceramics Bonaire
Fifteen minutes comparing slips colored with mason stain against bought underglaze. The description says the stain goes further than a pint of underglaze, and that making your own takes time and testing on your clay, glaze and firing temperature. The 44 recipes are in a free PDF linked from the description. Watch on YouTube
What a stain is, in four minutes Let's Talk Ceramic Stains Tiffany Bailey
Four minutes on what a ceramic stain is and what it colors. The description lists glazes, slips, washes and engobes, among others. Watch on YouTube

When it goes wrong

Six ways it goes wrong, and what to do about each.

The three failures that happen on the first tile.

Pick the one that looks like your tile. The first three are chemistry and mixing. The last three are percentage, fit and your lungs.

How it works here

At The Clay Hole, we sell the stains, and the reclaim is still sacred.

This page is written for potters everywhere. A few things are specific to our building.

Three things to know here

We stock 32 mason stains and sell them by the 25 grams on the mason stains page. They get paid for first and weighed out by the owner or the main hand building instructor. Coloring a batch of our clay with one is fine. Anything you bring in yourself still has to be cleared with the studio team before it goes into a kiln. Mix away from the shared tables with a fitted N95 or better on, and keep stained clay in its own bag. It never goes in the studio reclaim.

We stock these

We keep 32 mason stains and sell them by the 25 grams. Pick a color on the mason stains page, pay for it, and the owner or the main hand building instructor weighs it out. We still do not stock oxides or washes, and anything you bring in yourself has to be cleared with the studio team before it goes into a kiln, which is the rule for every outside material. The 150+ underglazes on the wall are mostly pigment with a little clay and flux, for the days you would rather buy one ready to go.

Coloring our clay

Stain wedged into clay from our shelves is still our clay, and it is welcome in the kilns once the studio team knows. Outside clay is not, stained or otherwise. Mix it away from the shared tables with a fitted N95 or better on, over a damp towel, and wipe down wet.

The reclaim

Stained clay never goes into the studio reclaim. A scrap of cobalt clay in the communal bucket is a blue speck in somebody else’s bowl months later. Your own bag, your own name, your own scraps taken home or binned. Wash and rinse water from stain work goes in its own bucket, never down the sink, so ask the studio team where the clear water goes.

Glaze and firing

The glaze wall needs the free brush-on glaze and underglaze certification. A stained slip made from our clay is fine once the studio team knows, but the only engobes approved here are the Mayco ones, so a homemade engobe is not. Any stained slip or wash is bisque fired before a glaze touches it, because unfired color lifts into the shared jars. A stained slip or wash under one of our clears fires with everything else at cone 5½. Bisque is cone 05 and free. For the glaze firing, several small tiles that fit on one 6 inch kiln cookie, a quarter inch apart and 125 cubic inches or less in total, pay as one piece. Every tile goes on a kiln cookie, and staff load every kiln here.

Questions people actually ask

The ones that come up every week.

What is a Mason stain?

A coloring pigment made by firing metal oxides with other minerals until they react into a crystal, then grinding it to a fine powder. Because it has already been fired, the color is stable and predictable, although the powder in the jar looks different from the fired color, which is why a tile comes first. Raw oxides are cheaper and wilder; stains are what you use when you want to know what you are getting. Mason is one brand; other suppliers make equivalents and the numbers cross-reference.

How much goes in?

Into a clay body, five to ten percent of the dry clay weight, up to fifteen for weak colors. Into a slip or engobe, five to fifteen percent of the dry weight. Into a glaze, two to ten percent, most colors between two and six. As a wash, equal parts stain and flux by dry weight, thinned with water until it looks like watercolor. Every one of those is a starting point for a test tile, not a recipe.

Why do some stains die in some glazes?

Chemistry. Chrome-tin pinks and maroons need calcium in the glaze and are killed by zinc. Some blues and greens are fine in almost anything. Encapsulated reds, oranges and yellows fade if fired hot. The jar or the supplier’s chart carries a compatibility note for every color; read it before choosing a base glaze, and test.

Is stained clay food safe?

A stained clay body under a fitted, fired clear glaze that the Food Safe Lookup clears for food is as safe as the glaze over it. Bare stained clay or a bare wash does not go on a food surface, so the answer is a coat of clear. Chrome, cobalt and the cadmium reds, oranges and Mango especially want covering and testing.

Stained slip or bought underglaze?

A bottled underglaze is the same idea with much less clay and much more pigment, plus a binder so it brushes well. Making your own is cheaper per pot, lets you match a color to your clay, and gives you a range of tints from one jar and a bucket of slip. Buying it is faster and it brushes better. The Nu Kua video on this page compares the two, and our wall has 150+ underglazes for the days you would rather buy.

Can I color clay at The Clay Hole?

We stock 32 mason stains and sell them by the 25 grams. They are paid for first and weighed out by the owner or the main hand building instructor. Coloring a batch of our clay with one is fine so far as the clay is ours, and anything you bring in yourself still has to be cleared with the studio team before it goes into a kiln. Weigh and mix it away from the shared tables with a fitted N95 or better on, and wipe everything down wet.

How do I keep the color even?

Wet the powder to a paste before it meets clay or slip. Into clay, knead the paste into softened clay and wedge far more than feels necessary, then cut the lump in half and look. Into slip, mix and then sieve through 80 mesh. Into glaze, sieve twice. Uneven stain is almost always dry powder that clumped.

Related lessons

Seven places to go from here.

Four to go to next.

A stain is a colorant. These are the things it colors, the tools that spread it, and the page where you buy one.

Buy oneMason Stains, by the GramAll 32 colors we stock, what each costs, and a calculator that works out how much you need. Surface and decorationEngobesThe coating side, and the clay colors we will never carry. Surface and decorationWipe-Away TextureThe wipe-back method for a wash, which the studio teaches with underglaze. Surface and decorationHow to Use UnderglazeThe bought version, and the rules for firing it. Surface and decorationCarving and SgraffitoStained clay and stained slip are what sgraffito was waiting for. Preparing your clayHow to Wedge ClayThe ram’s head method for the wedging. GlazingTest TilesOne per color per base, before any pot.

That is the whole technique

Pick the use. Read the jar. Mask on. Paste, then sieve or wedge. Tile before pot.

Your first stained clay will be marbled because you stopped wedging when your arms got tired, and your first stained glaze will be paler than the jar. That is normal, and the tiles will tell you which. One jar of a good blue and a bucket of slip is a whole range of tints, and the tile drawer is where they live.

If you want the chemistry, the food-safety notes, the dry-weight arithmetic and the answers to the questions everybody asks, switch to the comprehensive version at the top. Otherwise, go read the note on the jar.

Back to Clay Hole University The wash, wiped back

Written for potters everywhere. Where our studio does things differently, the page says so.