top of page

muse basket and canister process images

Studio Art Centers International, Florence, Italy  Summer Residency 2015 where the Muse Baskets were developed.
Painting on the gold luster for a cone  018 firing after bisque and interior glaze firings.
The muse basket is wrapped up and ready for the smudge firing
The temporary kiln for the smudge firing can be constructed as wished to contain the piece and allow air vents for irregular flame combustion

The Muse Baskets and Canisters are formed by a series of throwing, sculpting, and hand building techniques and then finalized through a multi step surface treatment and firing process. 

Terra sigillata is applied to the dry greenware, lightly burnished and bisque fired, then interior glaze is applied and fired, then gold luster is applied and fired, then the final smudge firing takes place in a temporary kiln structure and repeated until the desired layering and visual depth of surface is achieved. 

See below for further technical info and click on the Gallery Pages for images of finished pieces.

oceanware process images

Oceanware is formed in a variety of ways including throwing, hand building, and paddling. The glazes and colors are all made and developed in the studio by this potter.  for a bowl, a form is thrown, turned upside down and trimmed round, bisque fired, and becomes a mold to shape the interior. Then a slab is draped, formed, put back on the potter's wheel, and paddled upside down on top of the previously thrown and bisque fired mold to complete the exterior details. then the piece is allowed to dry completely. 

creating a  good form is crucial and is the foundation for all that follows.

**Bisque firing is a low temp firing in which the clay is hardened but left absorbent. a good state for applying glaze surfaces.**

After the piece is bisque fired, more surface treatments begin. First, any interior underglaze painting or staining is done, next the interior glaze is applied and any drips on the outside are cleaned up, Then the exterior staining is applied and wiped, and finally any exterior glaze application happens after that.

Application is crucial. Too thick or too thin application can ruin a piece. Much research and experimentation is needed to achieve the best results. properly firing the ware is also a critical and creative part of the process. A good functional piece not only needs to be technically sound and well designed for it's function but also well formed and aesthetically interesting. 

tiles process images

glaze Color Tests at cone 3

This group of tests are using my H6 cone 3 Clear glaze on Highwater Clays Buncombe White Clay with several colorants added in various proportions. All test tiles incorporate texture in the clay to show how the glaze performs on it and are either dipped with a double layer at top or poured with an overlap to show thick and thin application. 

Individual photos and more info on each test will follow below soon.

Glaze color test

 Recipes and Technical Info

Don's new cone 3 clear (h6)

by weight

epk (florida kaolin)....5

gerstley borate.............45

Nephyline syenite.......20

325mesh silica....................30


the above glaze goes a bit milky when thick and has a bright slightly waxy sheen to the surface;quite nice at cone 3 on a white, maturing clay body; no crazing.  apply thin if you want complete transparency. this is the glaze that i am currently using on oceanware. 

Don’s Clear Glaze cone 5-9 oxidation or reduction recipe

By Weight:


F-4 (Soda)Feldspar............25




Gerstley Borate.........10

Frit 3124..................20

Total 100

Try additions of various oxides for variations. Some suggestions:

1⁄4 % cobalt carbonate + 1⁄4 % chrome oxide will give a transparent blue/green....even smaller percentages can be very nice, somewhat like a celadon

1% cobalt carbonate makes a strong transparent blue

10% red iron oxide added offers a luscious breaking temmoku look in reduction

Remember: always test fire glazes first, before glazing your work.

Original Low Temp Transparent Glaze: 06

Gerstley Borate…..73


Nephyline Syenite..13



Add 3 % Copper Carbonate for transparent blue/green

Low Temp Separating Glaze cone 04 - 3

Gerstley Borate…………40

Nephyline Syenite………30  

Magnesium Carbonate…25

EPK………………………. 5


High Temp Separating Glaze cone 7-10

Nepheline Syenite……70

Magnesium Carb…….25



Cone 03 Clear Crackle & Green/ Blue from test Version e.

Gerstley Borate——60


Nephyline Syenite—18  




For Green/Blue add 3% Copper Carbonate


Don Davis Revised February 2009 & June 2017

These are higher in color concentration than my engobe recipes, which makes them better for some applications such as brushwork. Reminder: always test first!

The mixtures may be sprayed, sponged, poured, used for dipping or brushwork.

Apply like a thick slip on wet to leather hard green ware.

Apply thinned to a more watery consistency for use on bisque ware. These mixtures should fire to a satin surface on vitrified ware or may be used as an underglaze, coated with a transparent glaze. For the unglazed surface, thin coatings work best. Apply thicker if covering with glaze: especially Iron Red. You will have to adjust the water content to suit your individual applications.

These recipes are by volume (spoonfuls) not weight. I recommend using tablespoons. A nine tablespoon batch will yield about 1 quart after mixing.

Always dry mix ingredients before adding water. After dry mixing, add water, & stir with a hand held blender or whisk, then run through a 60-mesh screen.

The clay quality underneath and the firing temperature will affect the quality of the surface treatment. The less vilified, the drier they will feel if used without a glaze coating.

A white clay will yield more brilliant colors.

Clay fired to maturity will yield more gloss/sheen to the colors.

Dark clay bodies can be coated with white engobe to increase color brilliance.

If you need to adjust the mixture for your own needs:

To increase the melt add 1⁄2 spoonful frit or gerstley borate, decrease clay by the same amount. To decrease the melt/sheen do the opposite.


Original Black:

2 Mason 6600

2 Frit 3124


1/2 VeegumCer

Another Black:

1Mason 6600 Black

3 Red Art Clay

3 Ball Clay

2 Frit 3124

1/2 Veegum Cer

Warm Black:

1/2 MgO2 (Manganese Dioxide)

1/2 CoCO3 (Cobalt Carbonate)

6 Cedar Heights Red Art Clay

2 Frit 3124

1/2 VeegumCer

Red Brown:

8 Cedar heights Red Art Clay

1 Frit 3124

1/2 Veegum Cer

Fire to Cone 03-10

Iron Red:

2 Red Iron Oxide……2

2 Frit 3124……………4

5 EPK…………………3

1⁄2 Veegum Cer


1 Chrome Oxide

1/2 Cobalt Carbonate


3 Frit 3124

1/2 VeegumCer


2 Cobalt Carbonate

1/2 Chrome Oxide

2 Frit 3124

4 1/2 EPK

1/2 Veegum Cer


1 Cobalt Carbonate ……..1

1 Chrome Oxide……….…1/4

2 Fritt 3124………………..5

5 EPK………………………3

1⁄2 Veegum Cer

Ochre/ Straw Yellow:

1 1/2 Red Art Clay

2 Rutile

1 Fritt 3124

4 1/2 Tennessee #10 Ball Clay

1/2 Veegum Cer

Purple…in reduction firing (nice blue/black in oxidation)

1⁄2 Cobalt Carbonate

2 1/2 Copper Carbonate

5 TN 10 Ball clay

1 Fritt 3124

1⁄2 Veegum Cer

*VeeGum Cer is a ceramic gum that causes the engobe to flow better when brushing, to stay where you put it, and to dry harder for ease of handling. The mixture acts more like paint and less like a runny suspension of minerals in water. If it is unavailable, try any ceramic gum that is available. It is very important to dry mix gum with the other ingredients before adding water!

Finding and Processing Wild Clay for potential use

Finding and using wild clay can be an exciting and rewarding experience. Even if it doesn't prove to be a great clay for throwing or hand building you might  discover your own   unique surface treatment material.

Identifying clay as opposed to dirt.

Clay will usually appear as a distinct layer in both color & texture from the topsoil. It is a much finer particle size than dirt. It is very dense and hard when dry and feels slippery when damp. Dampen it and rub it between your fingers, if it is clay it will feel very slippery, not crumbly. You’ll know it is clay!

Clay is found all around us and may prove to be useful in different ways. Some clays that make good earthenware bodies will melt and become a glaze in a high temp firing. They may be useful as a component in a mixed clay body. Some found clays will make a good terra sigillata or engobe surface coating for color or textural contrast on your current clay body and not be useful at all as a clay body themselves. Look for clay where any digging is being done. Also look in places where water has cut into riverbanks. In some areas just digging a few inches down with a shovel may reveal a clay deposit.

Step 1

Collect your clay from as pure a source as possible; look for a place that appears to be consistent in color & texture; try to scoop it with as few roots, leaves, dirt, and rocks as possible. Get at least 3⁄4 of a 5 gallon bucket full for testing. You can put it in a box or bucket.

Step 2

Let it dry out. It helps to break it up and spread it out in a thin layer for maximum exposure to air. Try to find a warm, dry place to do this. If necessary, put it on trays in your oven at 200 degrees fahrenheit for a few hours.

Step 3

When clay is dry, crunch it up with a hammer in a low box. Wear a dust mask.

Step 4

Fill a 5-gallon bucket to about 1/3 full of water.

Pour in your clay until the bucket is about 2/3 full.

Let it soak for several hours.

Stir the mixture using a whisk and then use a mixing blade on an electric drill. You should end up with clay slurry, kind of like heavy cream.

*Make sure you save at least one pound of dry clay for a terra sigillata test.

Step 5

Run the clay slurry through a hardware cloth sized screen.

Then run it through a window-sized screen. If it is too thick to go easily through the screen stir more water into the slurry.

Throw away the debris collected in the screens.

This should be sufficiently screened for a clay body.

*If desired you can also run it through a 60 mesh screen for a finer clay. Do run about one quart through a 60-mesh screen and save for testing as an engobe.

Step 6

You now need to dry the rest to a workable state by spreading it out on an absorbent surface. Bisqued clay, a cloth sling or a plaster slab will all work. Watch it closely so that it doesn’t get too dry.

You will end up with enough clay to make test bars and also some to try forming a few pieces to find out how workable it is. Test your clay for shrinkage and porosity. We generally test at bone dry, cone 06, 5, & 9.


Terra sigillata is a thin solution of super fine clay applied to dry greenware before bisque firing. It burnishes very easily as soon as it dries to the touch and even though it is not vitreous it imparts a very pleasant shiny texture to the clay surface. It is used as an alternative to glaze or stain and offers both textural and color contrast to the clay surface. It works nicely in a variety of low temp firing methods ( cone 08-cone 1 or so) and because it is still porous it is not good for utilitarian ware but is especially attractive in pit, smoky, or smudge firings. It generally does not retain it's wonderful sheen at high temperatures.

To Make Terra Sigillata  

1) Put 1 quart water + 2 ml sodium silicate in a clear container and mix well

2) Add 1 pound of dry clay to water & sodium silicate, wait a few minutes, mix well.

3) Let it settle for 18-20 hours. You should see two or three distinct layers in the container: a thin layer of water on top, terra sig in the middle, & coarse particles on bottom. If there is a layer of water on top, pour it off or use a basting bulb to remove it. Now pour off ( or use the bulb) the middle layer of terra sig for use. Discard the material that settled to the bottom.

For some clays that are more coarse you will need to double the above recipe to get enough terra sig to test. Every clay will be different. Some clays don't easily show distinct lines between layers after settling, making it difficult to determine how much to use.  It is better to err on the side of decanting less terra sig in order to avoid the more coarse particles in the bottom layer.

We usually apply Terra sigillata with a fine brush to bone dry greenware. It will be quite thin compared to engobe and should quickly and easily burnish to a shiny surface when lightly rubbed as soon as it is dry to the touch. Two or three coats should be enough. Applying to a dusty surface or too thickly can cause problems with cracking. I usually use a thin piece of plastic over my finger for burnishing.


Engobes are liquid clay mixtures applied to leather hard ware as a decorative surface coating.

These Engobes are designed to be applied to moist-leather hard clay forms as a contrasting surface coating. They should be like thick cream and can be poured across the clay or brushed on in 1 or 2 coats. If you mix enough, leather hard ware can even be dipped into it. 

If it is applied too thick or when clay is too dry it may crack and peel off.

*This recipe is measured by weight*

1000 gram batch + water = approx. 1⁄2 gallon

*Dry mix before adding water!!

High Temp Engobe cone 5-10 


#6 Tile Clay………………… 250 grams

EPK (Florida Kaolin)……….250 grams

TN 10 Ball Clay……………. 250 grams

Frit 3124……………………. 100 grams

Nephyline Syenite…………..150 grams

Total…1000 grams


for black add: 20 grams Cobalt Oxide

50 grams Red Iron Oxide

50 grams Manganese Dioxide 30 grams Copper Carbonate

or 10% Mason 6600 Black Stain ( 100 grams per 1000 gram base batch)

for blue add 4.5 % cobalt carbonate and .5% chrome oxide 

for reddish brown add 3-7% red iron oxide

for white use base & 2% Tin Oxide or zircopax

for other colors test 3-10% stain

* Add 1 TblSp of Veegum Cer or T to the dry ingredients & dry mix well before adding water. This will aid dry strength and also aid the flow of the material for application.

This engobe is intended for application to soft through leather hard clay.

It may be applied by painting, dipping, pouring or spraying; adjust consistency for desired coverage.

It may be used with no glaze cover if a “dry look” is desired.

Cover with a clear or transparent glaze for a glossy finish. TEST FIRST BECAUSE Even a “clear” glaze can alter colors.

Remember, the quality of the clay serving as a background for the engobe will influence its appearance and quality.

Low Temp Engobes Fire to cone 06- 1 Don Davis

*Measure by weight* *Dry mix before adding water!*

1000 gram batch + water = approx. 1⁄2 gallon

Apply to damp/leather hard clay

Engobe White Base Recipe

Tennessee 10 Ball Clay....650 grams

Fritt 3124......................300 grams

Gerstley Borate................50 grams

Add 1 TblSp VeeGum Cer* to dry ingredients & mix before adding water to a consistency of thick cream for application. Run through a 60-mesh sieve.

* The Veegum Cer will add dry strength and also aid the flow of the material for application.

Blue Engobe

To white base add: 4.5% cobalt carbonate 0.5% chrome oxide

Copper Oxide Engobe - grey/green

To white base add:

5% Black Copper Oxide

Red-Brown Engobe

500 grams.......................Red Art Clay

150 grams.......................Tennessee 10 Ball Clay

300 grams.......................Fritt 3124

50 grams.......................Gerstley Borate

Add 1 TSP.........VeeGum Cer* & dry mix before adding water and hydrate to a consistency

similar to white engobe

For Black add the following to Red-Brown Base

3%................Red Iron Oxide

3%................Black Copper Oxide

1%................Cobalt Oxide

These mixtures are intended for application to leather hard ware and may be brushed, poured, or have ware dipped into them. Some adjustments to the water may be necessary according to technique (probably thinner for dipping).

They may be used with no glaze cover if a “dry look” is desired.

Cover with a clear or transparent glaze for a glossy finish. Test, because even a “clear” glaze can alter some colors.

Remember, the quality of the clay serving as a background for the engobe will influence its appearance and quality.

bottom of page