The materials, including colorants, should be dry sieved through an 80-mesh screen to ensure thorough blending. The amount of colorant can be up to 15 percent. More than that will cause a loss of plasticity in the raw state, making it difficult to form the pencils. The more colorant used, the more intense the color.
One way to test a glaze recipe for food safety, is to line a small cup with the glaze, fire it, fill it halfway full of vinegar and let it sit for 24 hours. Empty it, dry it, and look at it. If the texture or appearance of the glaze in contact with the vinegar changes in that time (becomes cloudy, chalky, etc.), discount it as unsuitable and do not use it on food-contact surfaces, as it will likely leach compounds into acidic foods and not resist washing detergents.
You may use Copper Carbonate, Iron Oxides and Manganese in small amounts (copper-1mg/liter, iron-0.3mg/liter, manganese-0.05mg/liter). Typically, once these minerals are fired at a very high temperature, they are no longer volatile.
You cannot use Aluminum, Chloride, Fluoride, Silver, Sulfate or Zinc in glaze or clay intended for food/water.
I copied all of the following recipes from the American Ceramics Society.
Glazes meant to be brushed on often have additional ingredients to enhance their flow off the brush and the evenness of their application. Some dipping glazes need no alteration for brushing, but if they do, the following approximate additions to one pound of dry glaze will help (test first with half the addition):
Add:
10.5 to 11.5 ounces of water (basic brushing glaze formula)
4.5 to 7.5 grams bentonite
2.3 to 3.4 grams CMC gum (first dissolved in warm water and aged overnight)
Note: 2 teaspoons equals 5-6 grams
Ideally, viscosity should be 2200 to 2500
When brushing a glaze, use as large a brush as reasonable with a smaller brush for hard to reach places. Use a full brush of glaze at all times. Dip the brush in the glaze and shake it gently, just sufficiently to prevent dripping. Do not scrape the brush on the top of the bottle or there will not be sufficient glaze on the brush to flow freely. Hold the brush lightly and flow the glaze off the brush in a continuous line and never "pat" glaze on randomly (except for special effects). Smooth the glaze by brushing back and forth very lightly. Begin the next stroke where the previous stroke ended and then lightly brush back over the area where the two strokes joined, which will adequately smooth out the "joint" between the two strokes. Apply subsequent coats in the same manner but in a different direction (for example, first coat horizontally, second vertically, and third, diagonally). Wait for the previous coat to dry thoroughly before applying another coat (A matter of a few minutes, After the first coat loses its wet "sheen").
Dipping glazes should be a thick cream consistency. An old "rule of finger" is that when a clean dry finger is dipped in a mixed dipping glaze, the glaze should coat the skin evenly and bead on the finger nail. The reality is that the glaze needs to be test fired on the properly bisque-fired clay body it will be used on. It should be of such consistency that a single dip, leaving the piece in the bucket several seconds, will provide the proper glaze thickness. A general mixing formula follows (use less water first or leave aside some dry glaze to allow adjustment):
Add to 1 pound dry glaze:
6.5 to 7.5 ounces of water
0.0 to 2.3 grams bentonite (if needed to maintain suspension)
Ideally, viscosity should be 900 to 1000
Glazes to be sprayed also require testing but the following can be used as a guide for mixing one pound of any glaze for spraying (always use a mask when spraying):
Add:
7.5 to 8.5 ounces of water
0.0 to 3.4 grams of bentonite
The viscosity should be 1500 to 1700
An almost endless number of special effects can be achieved by modifying the above techniques but should be tested first. Things to try include the following, individually or in combination (test first and avoid more than the recommended number of total coats):
Uneven application (usually less or watered down glazes unless on upper part of the piece where extra glaze won’t run off on to the shelf when fired).
Sponging or dappling or spritzing the same glaze or another glaze on top of the coat (or second coat if brushed —on glaze).
Overlapping a second adjoining glaze on the first color.
Strategically adding areas of underglaze over the glaze.
Using lower firing glazes (or underglazes) at higher temperatures either alone or over (or under) proper temperature glazes. Nearly all low fire (Cone 05-06) glazes and underglazes can be fired to Cone 5 or even higher but will lose some intensity (especially reds, pinks, and yellows). Be cautious though as the glazes will tend to run much more at the higher temperatures.
Underglaze Pens
Underglaze pens contain an “ink” that gives good flowability for drawing. They are available commercially from a number of producers, or you can make your own. You can also dip any form of “nibbed” pen, from fine-pointed mapping pens, to quills or sharpened bamboo, into ceramic ink.
Ceramic Ink Recipe
30g Gerstley borate
30g Potash feldspar
25g Ball clay
15g Silica
5g Bentonite
10g Black (6600) Mason Stain or other color
Ceramic Watercolor Recipe
50g Ball clay
25g Potash feldspar
25g Silica
3g Macaloid (or 5g Bentonite)
15g Mason Stain
For watercolors, the materials are mixed together, then enough water is added to make a slip, which is passed through an 80-mesh sieve and poured onto a plaster surface. When dry to the touch, watercolor cakes can be made by forming rounds or squares of the colored slip and letting them dry completely. They then can be used like ordinary cake watercolors by wetting the surface with water and applying with a brush.
Ceramic pencils are normally used on bisque-fired clay that has been sufficiently hardened to withstand the pressure needed for satisfactory marking.
Ceramic pencils may be used on the ceramic surface just like their graphite equivalent on paper. Although sharpened points tend to wear quickly on the abrasive ceramic surface, the combination of pencil tip marks, broad side marks, and the opportunity to create tones through finger-rubbing or smudging the soft image gives wide potential for drawn imagery development.
Ceramic pencil drawings can be fired onto the bisque-fired clay to harden them before glazing, or, alternatively, they can be fired on unglazed high-fired clays, such as porcelain or stoneware, without the need for a glaze coating.
Soft Ceramic Pencil Recipe
23g Ball Clay
23g Kaolin
23g Silica
23g Soda Feldspar
8g Bentonite
10-30g Pigment
1 oz. Sodium Silicate per 100g dry material
1 oz. Aloe Vera sap per 100g dry material
PVA glue
Mix 1 fluid ounce each of sodium silicate and aloe vera sap with 100 grams of dry material. Add pigment and knead until completely mixed. Roll into coils and dry thoroughly. Brush a light coat of pva glue on them and allow to dry.
Hard Ceramic Pencil Recipe
50g Porcelain slip
25g Potash feldspar
25g Silica
3g Macaloid (or 5g Bentonite)
15g Mason Stain
Mix the dry materials with approximately 45 percent water, to which 1 percent of sodium silicate per 100 grams of dry material mix has been added. This will slightly deflocculate the slip, giving additional green strength while also intensifying some of the colorants.
Form the pencils by drying the colored slip to a plastic state, and then either rolling out coils or extruding lengths of the desired thickness. These then can be left as pencil lengths or cut into shorter 1–2 inch lengths. When dry, fire the pencils to between 1472°F (800°C) and 1742°F (950°C), depending on the desired hardness. A lower firing will produce a softer pencil; higher firing, a harder pencil. The short lengths can be placed in a 5.6mm lead holder.
Mix the dry materials with approximately 45 percent water, to which 1 percent of sodium silicate per 100 grams of dry material mix has been added. This will slightly deflocculate the slip, giving additional green strength while also intensifying some of the colorants.
Form the pencils by drying the colored slip to a plastic state, and then either rolling out coils or extruding lengths of the desired thickness. These then can be left as pencil lengths or cut into shorter 1–2 inch lengths. When dry, fire the pencils to between 1472°F (800°C) and 1742°F (950°C), depending on the desired hardness. A lower firing will produce a softer pencil; higher firing, a harder pencil. The short lengths can be placed in a 5.6mm lead holder.
Pastels
Pastels normally are used from the greenware state and are not prefired unless they prove too friable for convenient use. To make pastels, use the basic recipe above and simply form the clay into coils or extrusions to the desired size for use. If they prove too fragile, they can be fired to between 1112°F (600°C) and 1472°F (800°C) without making them excessively hard. Ceramic pastel drawings should be fired on the ceramic object to harden them before a glaze is applied; otherwise, the powdery surface likely will be spoiled in glaze application or handling. Surface powder also might cause crawling through lack of glaze adhesion.
Crayons
To make wax crayons, mix the dry recipe above with wax resist. Form the crayon, and let it dry. Since the crayon will contain some latex, it also will have a slight resist effect on the work, particularly when used on bisquefired ware. For a crayon with greater resist qualities, stir colorants into wax, let cool, roll the wax into rods of different widths, and cut the rods in convenient lengths.
Engobe Recipe
Engobe is a gel slip applied to greenware.
| Raw Material | Cone 4-3 | Cone 4-6 | Cone 6-10 |
| Kaolin | 20 | 15 | 15 |
| Calcined Kaolin | 10 | 20 | 35 |
| Talc | 25 | 10 | 5 |
| Calcium Borate | 15 | 10 | 0 |
| Nepheline Syenite | 0 | 10 | 15 |
| Silica | 15 | 20 | 15 |
| Borax | 5 | 5 | 5 |
| Zircopax | 10 | 10 | 10 |
| Total | 100% |
Sieve all materials with an 80 mesh sieve. Add enough water to make a slurry. Add 0.2-0.3g of Epsom salt to make it gel and mix with an immersion blender. Dip greenware.
Underglaze Recipe
33.3g Ferro Frit 3124
33.4g EP Kaolin
33.3g Mason Stain
Sieve all materials with an 80 mesh sieve and then ball mill for at least 12 hours. Incorporate Sta Flo Laundry Starch until the mixture reaches a thin yogurt consistency and sieve the entire mixture again. Brush onto greenware.
Low Fire Glazes, Cone 04 oxidation
Gloss Glaze Recipe
30g Ferro Frit 3124
30g EP Kaolin
40g Silica
15g Mason Stain
Satin Glaze Recipe
50g Ferro Frit 3195
20g EP Kaolin
30g Dolomite
15g Mason Stain
Matte Glaze Recipe
43g Ferro Frit 3195
14g EP Kaolin
43g Calcium carbonate
15g Mason Stain
Mid Fire Glazes, Cone 05 oxidation
Transparent Gloss Crackle Glaze Recipe
90g Ferro Frit 3110
10g EP Kaolin
5g Mason Stain
Transparent Gloss Glaze Recipe
30g Gerstley borate
46g F-4 Feldspar
13g EP Kaolin
11g Silica
1g Mason Stain
Opaque Gloss Textured Glaze Recipe
52.6g Gerstley borate
21g EP Kaolin
26.4g Silica
10g Zircopax
1g Mason Stain
Semi-opaque, Semi-satin Textured Glaze Recipe
9.5g Calcium carbonate
44.5g Ferro Frit 3124
20g F-4 Feldspar
5.5g Zinc Oxide
7.5g Bentonite
5g EP Kaolin
8g Silica
9g Zircopax
1g Mason Stain
Opaque Satin Textured Glaze Recipe
12g Dolomite
14g Gerstley borate
10g Wollastonite
8g Ferro Frit 3124
46g Cornwall Stone
10g EP Kaolin
6g Magnesium carbonate
1g Mason Stain
Clay body: Super White (cone 5–9) a white stoneware body for mid-range.
Mid Fire Glazes, Cone 06 oxidation
Gloss Glaze Recipe
7.6g Barium carbonate
18.5g Gerstley borate
6.5g Talc
2.1g Calcium carbonate
41.3g Custer Feldspar
24g Flint Silica
102.4g Mason Stain
Dark Matte Glaze Recipe
18.4g Barium carbonate
8g Gerstley borate
36.8 Custer Feldspar
18.4g Barnard clay
9.2g EP Kaolin
9.2g Flint Silica
17.2g Mason Stain
Eggshell Glaze Recipe
9.5g Calcium carbonate
5.5g Zinc Oxide
44.5g Ferro Frit 3124
20g Custer feldspar
7.5g Bentonite
5g EP Kaolin
8g Flint Silica
9g Tin Oxide
3g Mason Stain
Must be sprayed very thinly.
High Fire Glazes, Cone 08-11 reduction
Gloss Opaque Glaze Recipe
2.55g Baroum carbonate
5.61g Dolomite
9.18g Gerstley borate
8.68g Calcium carbonate
53.57g Custer Feldspar
2.55g EP Kaolin
17.86g Silica
2.04g Tin Oxide
0.61g Mason Stain
Swirl Gloss Opaque Glaze Recipe
21.2g Calcium carbonate
2.7g Zinc Oxide
24.9g Custer Feldspar
8.8g Ferro Frit 3110
17.5g EP Kaolin
24.9g Flint Silica
0.7g Tin Oxide
0.9g Green 6201 Mason Stain
1.6g Blue 6391 Mason Stain
The mason stains may be any two coordinating colors or 2.5g of a single color.
Ash Glaze
50g Wood or Vegetation Ash
50g Red Art or Plastic Vitrox Clay
2-3g Mason Stain
The ashes from any wood or vegetation such as grass or leaves will work for an ash glaze.
To begin, prepare ashes by running them through a flour sifter to remove unburned wood, charcoal and big chunks of debris, then run the dry ash through a 40-mesh screen.
After mixing with water, run the glaze through a 40-mesh screen then through an 80-mesh screen to get it to the right consistency for spraying. Use a thinner glaze than you would for dipping or pouring.
Work with the spray gun about 5-12 inches from the surface and use steady even strokes to avoid getting excess glaze in any one spot where it can drip. Use a sponge to clean the footring.
Tableware Clear Glaze, Cone 01-8 oxidation
Food Safe
Dip 3 times
50g Ferro Frit 3134
20g Mahavir Potash feldspar
20g Ball clay
10g Magnesium carbonate (light)
20g Mahavir Potash feldspar
20g Ball clay
10g Magnesium carbonate (light)
Milky White, add 10g Tin Oxide
Light Cream, add 1g Red Iron Oxide
Soft Green, add 0.5g Chrome Oxide Green
Light Green, add 1g Cooper Carbonate
Moss Green, add 2g Copper Carbonate
Soft Blue, add 1g Cobalt Carbonate
The colorants are fired to Cone 04 oxidation to achieve the given results.
Flameware Glazes, Cone 10
Interior Glaze
9.2g Bone Ash
9.7g Iron Oxide
5.6g Pioneer Talc
6.6g Calcium Carbonate
43.9g Custer Feldspar
5.6g EP Kaolin
19.4g Flint Silica
2g Bentonite
Exterior Glaze
28g Calcium Carbonate
48.37g Custer Feldspar
10.74g EP Kaolin
12.89g Flin Silica
8.6g Titanium Dioxide
2.15g Bentonite
Gray/Black, add 6-8g Manganese
Gold, add 5-8g Buff Titanium Dioxide
Blue, add 0.625g Cobalt Carbonate
Green, add 3g Copper Carbonate
Gray Green, add 1g Copper Carbonate + 2g Nickel
Blue Green, add 0.625g Cobalt Carbonate + 4g Titanium Dioxide + 5g Copper Carbonate
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