# How to Make Glazes for Pottery from Dry Materials

Source: https://potterynest.com/blog/how-to-make-pottery-glaze
Published: 2026-10-08
Publisher: Pottery Nest

To make a glaze for pottery, you weigh out dry materials from a recipe, add them to water, pass the slurry through an 80 mesh sieve and adjust the water until it coats a test tile in an even layer. Every glaze is built from three things: silica to form the glass, a flux such as feldspar, whiting or a frit to make that glass melt at your firing temperature, and clay to supply alumina so the melt stays on the pot instead of running off. The recipe fixes the ratio of those three, and the colorants and suspenders are added on top. The work itself is simple kitchen-scale chemistry. What separates a usable glaze from a ruined kiln shelf is matching the recipe to your cone, weighing accurately, sieving properly and firing a test tile before you trust a bucket.

## What every glaze is made of

A fired glaze is a thin layer of glass, and glass needs a glass former, a flux and a stabilizer. The glass former is silica, sold as a fine 325 mesh powder and also carried into the recipe by feldspar and clay. The flux is whatever lowers the melting point of silica to something a kiln can reach: feldspar, whiting (calcium carbonate), dolomite, talc, zinc oxide, nepheline syenite, or a manufactured frit. The stabilizer is alumina, which comes almost entirely from kaolin or ball clay and keeps the melted glass viscous enough to cling to a vertical wall.

The ratio shifts with the firing temperature. Low fire glazes around cone 06 to 04 rely on boron frits such as Ferro 3124 or 3134 because feldspar alone will not melt that cool. Mid fire cone 5 to 6 glazes, the most common home kiln range, use a mix of feldspar, whiting, talc or dolomite and often a little frit or Gerstley borate substitute. Cone 10 glazes can be as simple as feldspar, whiting, silica and kaolin. A recipe for one cone will not work at another: a cone 10 glaze fired to cone 6 stays dry and rough, and a cone 06 glaze fired to cone 6 runs off the pot.

Recipes are written as percentages that add up to 100 for the base. Colorants, opacifiers and suspension aids are listed separately as additions on top of that 100, for example 2 percent bentonite or 1 percent cobalt carbonate. Keep that convention in your own notebook so a recipe you wrote in March still makes sense in October.

## Equipment and safety before you open a bag

You need a digital scale, two buckets or large yogurt tubs, an 80 mesh sieve, a stiff brush or a flexible rib to push material through the sieve, measuring cups for water, a drill mixer or a sturdy whisk, and a notebook. For 100 gram test batches, a scale that reads to 0.1 gram makes colorant additions accurate; for 5,000 gram buckets, a kitchen scale reading to 1 gram is fine. A set of plastic cups for weighing each material separately avoids the error of overshooting one ingredient in a shared container.

Dry glaze materials are the most dangerous dust in a pottery studio. Silica, feldspar and clay all contain free silica fine enough to reach the lungs, and the damage from repeated exposure is permanent. Wear a respirator with P100 particulate filters whenever dry powder is open, not a paper dust mask, and keep it on until the powder is wet and the surfaces are wiped. Some colorants add their own hazards: manganese, chrome, cobalt and nickel compounds should be handled with gloves and never allowed to dry on a work surface. Barium carbonate is toxic if swallowed and is best left out of home recipes, and lead has no place in a home studio at all.

Clean up wet. Sponge the bench and floor rather than sweeping, and rinse the sieve and buckets outdoors or in a sink with a sediment trap so glaze material does not set in the drain. Keep food and drinks out of the mixing area.

[See our studio safety gear picks](https://potterynest.com/best/best-pottery-studio-safety-gear)

## Choose a recipe that matches your cone

Start with a published base glaze for the exact cone you fire to, then learn to color it, rather than inventing a recipe from scratch. Published recipes come from glaze books, ceramics magazines, community studios and the open recipe database Glazy, and the good ones list the cone, the atmosphere (oxidation for electric kilns) and photos of the result on named clay bodies. Pick one that was fired in oxidation if you use an electric kiln, because recipes written for gas reduction look completely different in an electric kiln.

Two classic starting points show how simple a base can be. For cone 10, the Leach 4-3-2-1 glaze is 40 percent potash feldspar, 30 percent silica, 20 percent whiting and 10 percent kaolin, a clear to semi-clear glaze that takes colorants well. For cone 06, a common clear starts at roughly 90 percent of a boron frit such as Ferro 3124 with 10 percent kaolin to keep it in suspension. Cone 6 bases are more varied, so take one from a trusted source and write down where it came from.

A clear or white base glaze is the most useful first batch because it tells you two things at once: whether the recipe melts properly at your cone and whether it fits your clay without crazing. Once a clear base works on your clay, every colorant and stain you add to it is a small, predictable change rather than a new experiment. If you would rather see how a well-behaved clear should look before mixing your own, our clear glaze guide covers brush-on and dipping clears from cone 06 to cone 6.

[Compare ready-made clear glazes](https://potterynest.com/best/best-clear-glazes)

## Mix a 100 gram test batch step by step

A 100 gram batch is the standard test size because the recipe percentages become grams, so no arithmetic is needed. Put a cup on the scale, tare it to zero, weigh the first material, tip it into a dry bowl, then tare again for the next. Weigh each material on its own rather than adding to one cup, because an overshoot of 3 grams on a 10 gram ingredient is a 30 percent error that cannot be taken back out. Weigh the colorants and bentonite last and record every figure as you go.

Measure about 80 to 100 milliliters of water into a tub, then add the dry mix to the water, not the other way round. Adding powder to water keeps the dust down and stops lumps forming at the bottom. Let it sit for ten or fifteen minutes so the clay slakes, then stir with a whisk or small mixer until smooth. Pass the slurry through the 80 mesh sieve into a second tub, pushing it through with a brush, then sieve it back the other way. Two passes break up the clay lumps and colorant specks that show up as spots on the fired tile.

Dip or brush the glaze onto two or three test tiles made from your own clay, ideally with a vertical face and a textured patch, and apply one tile thicker than the others so you can see how the glaze behaves as thickness changes. Write the recipe code on the back with an underglaze pencil or iron oxide before glazing. Fire the tiles with a witness cone next to them so you know the glaze was judged at the temperature you think it was.

[Check pyrometric cone options](https://potterynest.com/best/best-pyrometric-cones)

## Scale up to a bucket and set the thickness

Once a test tile looks right, multiply every figure by the same factor. A 5,000 gram dry batch mixed with roughly 4 to 5 liters of water fills a 5 gallon bucket to a level that lets you dip a mug without spilling, and that is the size most home potters settle on for a favorite glaze. Weigh the big batch the same way, one material at a time, and sieve it twice through 80 mesh even though it takes longer with a bucket. A drill mixer saves your arm here and gets the material off the bottom of the bucket properly.

Thickness is the setting you control after mixing, and it is set with water. Most dipping glazes work at a specific gravity between about 1.4 and 1.5, which you can measure by weighing exactly 100 milliliters of stirred glaze: 145 grams means a specific gravity of 1.45. Record the figure that gives you a good coat, because the same number will get the next bucket right first time. If the glaze is too thin, let it settle overnight and pour clear water off the top; if too thick, add water a little at a time.

A mixed glaze needs to stay in suspension long enough to dip. Two percent bentonite, dry-mixed into the batch before any water is added, keeps most glazes from settling into a hard cake. If a glaze still drops out quickly, a saturated solution of Epsom salt added a few drops at a time while stirring thickens the slurry and holds the particles up. If weighing raw materials is more than you want to take on, bagged dry glazes come as a finished recipe that only needs water and the same sieving and thickness routine.

[See our dipping glaze picks](https://potterynest.com/best/best-dipping-glazes)

## Add color and test it properly

Colorants go in as a percentage on top of the base and small amounts go a long way. The ranges potters use in an electric kiln are roughly: cobalt carbonate 0.5 to 2 percent for blue, copper carbonate 2 to 5 percent for green, red iron oxide 2 to 10 percent for honey through brown to near-black, rutile 4 to 8 percent for mottled tan and cream, chrome oxide 0.5 to 2 percent for opaque green, and manganese dioxide 2 to 6 percent for browns and purples. Ceramic stains are more predictable than raw oxides and are typically added at 5 to 10 percent. Tin oxide at 5 to 8 percent or zircopax at 10 to 15 percent turns a clear into an opaque white.

Test colorants with a line blend rather than guessing. Mix the base, split it into five cups, and add the colorant at five levels, for example 0.5, 1, 1.5, 2 and 3 percent cobalt, so one firing shows the whole range. Keep the percentages in your notes next to a photo of the fired tile. The same method works for comparing two bases or two stains. Raw oxides and stains behave differently in matte and glossy bases, so a stain that is perfect in a gloss clear may look chalky in a matte and should be retested if you change the base.

[See our ceramic stain and colorant picks](https://potterynest.com/best/best-ceramic-stains)

## Fixing fit and the usual first-batch mistakes

Crazing, the network of fine cracks over the whole surface, means the glaze shrank more than the clay as it cooled. The standard fix is to add silica in steps of 5 percent, which lowers the glaze's expansion, and to retest. Reducing the high expansion fluxes, mainly soda and potash from feldspar and nepheline syenite, works in the same direction. The opposite fault, shivering, where flakes of glaze pop off rims and edges, is rarer and is corrected by taking silica out or adding a high expansion flux.

A glaze that runs off the pot and onto the shelf is either too thick, too high in flux for the cone, or fired hotter than planned, so check the witness cone before changing the recipe. A rough, dry, underfired surface is the reverse: not enough flux, or a recipe written for a hotter cone. Pinholes and small craters usually trace back to a thick coat, dusty bisque or a fast firing rather than the recipe itself. Specks and bumps on the surface almost always mean the batch was not sieved twice, and a cake on the bottom of the bucket means the bentonite was left out or added as dry powder to a wet glaze, where it refuses to disperse.

## Frequently asked questions

How much does it cost to mix your own glaze? A 50 pound bag of feldspar, silica or whiting is inexpensive per pound, and a 5,000 gram bucket of a basic cone 6 base generally costs a small fraction of the same volume bought as a ready-made brushing glaze. The savings are real once you fire regularly, but the first order of six or seven raw materials plus a sieve, scale and respirator is the real cost of entry, which is why most potters start with one clear base and add a stain rather than stocking a full palette of oxides.

Is a homemade glaze food safe? Only if the base is well melted, fits the clay without crazing and uses colorants in modest amounts. Glazes with high copper, manganese or chrome, any barium, or a matte surface produced by underfiring are the ones most likely to leach. A simple home check is to leave a slice of lemon or a splash of vinegar on the fired surface overnight: any change in color or sheen means the surface is attacked and the glaze should be kept for the outside of pots. A commercial leach test is the only real proof for ware you sell.

How long does mixed glaze keep? Indefinitely, as long as the bucket is covered so it does not dry out. Water evaporates and the glaze thickens over time, so stir it from the bottom, check the specific gravity and re-sieve it if it has sat for months, because settled clay and colorant form lumps. A sour smell or surface mold on an old bucket is harmless to the glaze and clears with a stir.

Can I make glaze from wood ash or found clay? Yes, and both are traditional, but neither is a beginner shortcut. Wood ash is a strong, variable flux that has to be washed, sieved and tested in blends with feldspar and clay, and most ash glazes are cone 9 to 10 recipes. Local clay can work as the alumina and silica source in a high fire slip glaze. Both need the same test tile discipline as any other recipe, with more batches, because the raw material changes from one bag to the next.

## Related buying guides

- https://potterynest.com/best/best-dipping-glazes
- https://potterynest.com/best/best-ceramic-stains
- https://potterynest.com/best/best-pottery-studio-safety-gear
- https://potterynest.com/best/best-clear-glazes