Archive for March, 2015

  • Jingdezhen

    Sanbao Porcelain Stone and Saggar Kiln

    Nestled in the beautiful mountains near Jingdezhen is Sanbao, a traditional source of porcelain stone. Porcelain stone comes in many types characterized by the local geography. Sanbao stone is primarily used in making porcelain bodies, but it can also be used in glazes.

    Worker removing porcelain stone from the Sanbao mine (May 2012)

    This wooden tool ensures equally sized porcelain bricks.

    Porcelain bricks are air-dried on wooden racks.

    A shrine at the mine.

    A workshop near the porcelain stone mine specializes in making kiln saggars.

  • Glazes

    Ash Glazes

    All of the following ash glaze recipes and more can now be found on my new open-source ceramics recipes website, Glazy:  http://glazy.org/search?category=36&subcategory=96

    I’m not particularly an ash glaze aficionado, and I’m far from an expert.  But it’s surprisingly easy to make an interesting ash glaze, and it’s nice to have some “natural” glazes which give interesting surfaces on functional ware.  

    The digitalfire website has safety tips for mixing and using ash glazes.

    At the bottom of this article is a list of resources for learning more.

    Wood stove ash with local stoneware

    A great way to make an ash glaze is to mix any type of ash with your stoneware body.  A line blend of ash from 40-60% is a good place to start.

    Below are tests of a local Jiangxi stoneware body, Tianbao, mixed with unwashed ash from my wood stove.  Glazes dipped onto bisqued porcelain and dark stoneware tiles, then fired in reduction to Orton Cone 10.

    Stoneware 40% Wood Ash 60%. Orton Cone 10 Reduction.

    Stoneware 40% Wood Ash 60%. Orton Cone 10 Reduction.

    Stoneware 50% Wood Ash 50%. Orton Cone 10 Reduction.

    Stoneware 50% Wood Ash 50%. Orton Cone 10 Reduction.

    Rice Straw Ash with Local Stoneware

    Below are tests of a local Jiangxi stoneware body, Tianbao, with Rice Straw Ash.

    Clay 60% Straw Ash 40%. Orton Cone 10 Reduction.

    Clay 50% Straw Ash 50%. Orton Cone 10 Reduction.

    Clay 40% Straw Ash 60%. Orton Cone 10 Reduction.

    Glaze Ash with Local Stoneware

    Below are tests of a local Jiangxi stoneware body, Tianbao, with a traditional Jingdezhen glaze ash called Er Hui.

    20% Glaze Ash

    30% Glaze Ash

    40% Glaze Ash

    50% Glaze Ash

    High Fire Glazes Ash Recipes

    Some ash glazes from The Complete Guide to High Fire Glazes  All tests fired to Orton Cone 10 in reduction.

    Basic Ash

    Titus-Zella Wood Ash

    This recipe, listed in High-Fire Glazes, is simply 50% wood ash and 50% custer feldspar.

    Basic Aerni Ash

    Zellar Ash

    Other Ash Glaze Recipes

    Leach Ash

    As posted by Tom Turner (link below).  He says: “I do not wash ash as I believe much of the character is in what is washed away. Dry sieve through a 30 mesh sieve.”  I used a 60 mesh sieve.

    Leach’s Basic Ash Glaze
    Wood Ash 40
    Feldspar 40
    Ball Clay 20

    Libby Pickard Ash Glaze

    From Phil Rogers Ash Glazes, p. 85:
    https://books.google.com/books?id=th3JZzIFFYQC

    Also listed on Glazy:  http://glazy.org/recipes/4407

    Tenmoku with Rice Straw Ash

    This glaze is from a University of Texas online glaze database (approx 2004) at: http://general.utpb.edu/fac/stanley_c/
    http://general.utpb.edu/fac/stanley_c/formulae/glaze/tenmokus.htm

    More information on Glazy:  http://glazy.org/recipes/3500

    Synthetic (Fake) Ash

    You must burn a lot of wood or plant matter to make a small amount of useable ash.  The sieved, unwashed ash collected after a Winter burning my small wood furnace only gives me enough material to make a couple buckets of 50% clay 50% ash glaze.  Furthermore, I burn whatever type of wood happens my way, and it often contains impurities like dirt and nails.  So besides the limited quantity I have available, there is also a question of consistency.

    Substituting part or all of real ash with synthetic ash in a glaze recipe is one method to address the problems of impurities, variability, and supply.

    For most of these tests I just made a simple 50/50 mix of the synthetic ash recipe with a local stoneware body in order to compare to my previous real wood ash glazes.  The following tests were all fired to Orton Cone 11 in reduction.

    Robert Tichane's Recipe

    Robert Tichane’s excellent book Ash Glazes has a chapter devoted to synthetic ash glazes.  Based on Dr. Emil Wolff’s analysis of Beech wood ash, Tichane creates the following synthetic ash:

    • Limestone: 75 g (43.2%)
    • Dolomite: 50 g (30.8%)
    • Potassium Carbonate: 25 g (15.4%)
    • Bone Ash: 6 g (3.7%)
    • Sodium Carbonate: 5 g (3.1%)
    • Calcium Sulfate: 3 g (1.9%)
    • Silica: 2 g (1.2%)
    • Sodium Chloride: 0.2 g (0.1%)
    • Ferric Oxide: 1 g (0.6%)

     

    Robert Tichane's Synthetic Ash 100%

    As you can see in the third picture, the soluble salts tend to permeate bisque ware, possibly decreasing body melting temperature and increasing warping.  (It would be interesting to compare the effects of solubles on a raw-glazed tile.)  Solubles are troublesome for other reasons, of course.  Water should not be removed from an already mixed glaze batch, and safety is a concern.

     

    Tichane Synthetic Ash 100%. Porcelain, Orton Cone 11 Reduction.

    Tichane Synthetic Ash 100%. Stoneware, Orton Cone 11 Reduction.

    Tichane Synthetic Ash 100%. Porcelain, Orton Cone 11 Reduction.

    Robert Tichane's Synthetic Ash 50%, Stoneware 50%

    Tichane’s recipe is interesting because of the soluble components that emulate unwashed wood ash.  And of all the synthetic ash recipes I tested, Tichane’s comes closest to the feel of real unwashed wood ash glazes.

    Porcelain, Orton Cone 11 Reduction.

    Stoneware, Orton Cone 11 Reduction.

    Maritaro Onishi's Recipe

    Ash Glazes also contains a recipe for synthetic ash by Maritaro Onishi:

    • Limestone: 62%
    • Feldspar: 12%
    • Bone Ash: 7%
    • Magnesite (Magnesium Carbonate): 5%
    • Kaolin: 10%
    • Silica: 3%

    Maritaro Onishi's Synthetic Ash 50%, Stoneware 50%

    Tichane notes that impurities in the feldspar and kaolin may add iron and manganese.  However, in my test I added an additional 2% red iron oxide and 1.2% manganese dioxide.

    Porcelain, Orton Cone 11 Reduction

    Stoneware, Orton Cone 11 Reduction

    Etsuzo Katou's Recipe

    John Neely on the Clayart mailing list mentions Etsuzo Katou who published another synthetic ash recipe, Ueda synthetic ash #3:

    • Whiting: 59%
    • Potash Feldspar: 22%
    • Magnesium Carbonate: 11%
    • Bone Ash: 5%
    • Red Iron Oxide: 2%
    • Manganese Dioxide: 1%

    Etsuzo Katou's Synthetic Ash 50%, Stoneware 50%

    I accidentally used 2% Manganese in my test glaze.

    Porcelain, Orton Cone 11 Reduction

    Stoneware, Orton Cone 11 Reduction

    Joseph Grebanier's Recipe

    In chapter 13 of Chinese Stoneware Glazes, Synthetic Wood Ash, Joseph Grebanier compares various wood ash analyses and questions the accuracy of Onishi’s synthetic ash formula.  Using Herbert Sanders’ ash analyses in The World of Japanese Ceramics,  Grebanier creates the following recipes:

    Grebanier’s Batch Recipe for Synthetic “Common Ash”:

    • Whiting: 35.73%
    • Buckingham Feldspar: 24.35%
    • Kaolin: 10.39%
    • Flint: 10.11%
    • Magnesium Carbonate: 6.86%
    • Bone Ash: 4.09%
    • Soda Ash: 3.90%
    • Red Iron Oxide: 3%
    • Manganese Dioxide: 1.32%

    Grebanier’s “Common Ash” recipe was later simplified by Phil Rogers in Ash Glazes:

    • Whiting: 36%
    • Buckingham Feldspar: 25%
    • Kaolin: 10%
    • Flint: 10%
    • Magnesium Carbonate: 7%
    • Bone Ash: 5%
    • Soda Ash: 4%
    • Red Iron Oxide: 3%
    • Manganese Dioxide: 1%

    Grebanier’s Batch Recipe for Synthetic Pine Ash:

    • Whiting: 44.37%
    • Orthoclase: 36.17%
    • Magnesium Carbonate: 6.36%
    • Soda Ash: 4.38%
    • Bone Ash: 4.1%
    • Red Iron Oxide: 2.31%
    • Manganese Dioxide: 2.28%

    Grebanier’s Pine Ash recipe was later simplified by Robert Tichane in his Ash Glazes:

    • Whiting: 44.4%
    • Feldspar: 36.2%
    • Magnesium Carbonate: 6.4%
    • Soda Ash: 4.4%
    • Bone Ash: 4.1%
    • Red Iron Oxide: 2.3%
    • Manganese Dioxide: 2.3%

    Grebanier's Synthetic Common Ash Recipe (simplified)

    In the following tests I substituted Buckingham Feldspar for my local Potash Feldspar.

    50% Stoneware, %50 Synthetic Ash. Porcelain, Orton Cone 11 Reduction

    50% Stoneware, %50 Synthetic Ash. Stoneware, Orton Cone 11 Reduction

    40% Stoneware, %60 Synthetic Ash. Porcelain, Orton Cone 12 Reduction

    40% Stoneware, %60 Synthetic Ash. Stoneware, Orton Cone 12 Reduction

    Leach’s Basic Ash Glaze. Wood Ash (sub Synthetic Ash) 40, Feldspar 40, Ball Clay 20. Porcelain, Orton Cone 12 Reduction

    Leach’s Basic Ash Glaze. Wood Ash (sub Synthetic Ash) 40, Feldspar 40, Ball Clay 20. Stoneware, Orton Cone 12 Reduction

    Grebanier's Synthetic Pine Ash Recipe (simplified)

    Stoneware Body 50%, Synthetic Pine Ash 50%. Porcelain, Orton Cone 12 Reduction

    Stoneware Body 50%, Synthetic Pine Ash 50%. Stoneware, Orton Cone 12 Reduction

    Synthetic Ashes in Low-iron Glazes

    Many white, clear, and celadon glazes in antiquity were at least in part comprised of plant or tree ash.  By varying the amount of synthetic ash and coloring oxides (mostly iron and manganese) you can quite easily produce some nice glazes.

    One of the most important lessons to learn from using synthetic ash is not necessarily to reproduce the look/effect of natural ashes, but rather to understand the result of introducing a wider variety of oxides into the glaze mix.  For instance, take a common celadon recipe, Hamada 5-3-2 (50% custer feldspar, 30% silica, 20% whiting) which is primarily fluxed with lime.  What happens when we introduce extra sodium, potassium, magnesium, phosphorus, iron and manganese to the mix?

    Grebanier Synthetic Common Ash and Porcelain Body

    One of my favorite ways of making new glazes is to simply mix a flux or ash with a clay body.  This method is usually used with iron-rich stonewares but works just as well for cleaner stoneware and porcelain bodies.

     

    Porcleain Body 60%, Synthetic Wood Ash 40%. Orton Cone 12 Reduction

    Porcleain Body 50%, Synthetic Wood Ash 50%. Orton Cone 12 Reduction

    Porcleain Body 40%, Synthetic Wood Ash 60%. Orton Cone 12 Reduction

    Grebanier Synthetic Common Ash, reduced Iron and Manganese

    For the following three tests, the amount of Iron and Manganese in the synthetic ash was reduced to 1/3 of the original amount.

    The first test results in a lovely semi-matte glaze, while the last two tests are passable celadons.

    Porcleain Body 60%, Synthetic Wood Ash 40%. Orton Cone 12 Reduction

    Porcleain Body 50%, Synthetic Wood Ash 50%. Orton Cone 12 Reduction

    Porcleain Body 40%, Synthetic Wood Ash 60%. Orton Cone 12 Reduction

    Grebanier Synthetic Common Ash and Feldspar

    This is basically the Titus-Zella Wood Ash above.

    Potash 60%, Synthetic Wood Ash 40%. Orton Cone 12 Reduction

    Potash 50%, Synthetic Wood Ash 50%. Orton Cone 12 Reduction

    Adjusting the Feldspar/Synthetic Wood Ash glazes

    For the potash feldspar/synthetic wood ash mixes above, I reduced the amount of iron and manganese (1/3 of original recipe) as well as added silica to reduce crazing.  With 10% Silica we’ve eliminated the crazing.

    Potash 55%, Silica 5%, Synthetic Wood Ash 40%. Orton Cone 12 Reduction

    Potash 50%, Silica 10%, Synthetic Wood Ash 40%. Orton Cone 12 Reduction

    Making Your Own Synthetic Ash

    Chemical analyses of ash vary widely, even analyses by different people of the same type of ash.  But chemical analyses are a good starting point for experimentation.  Synthetic ash recipes can be calculated by hand (see Chapter 13 of Nigel Wood’s Chinese Glazes) or by using glaze software.

    I was interested in Issu wood ash, commonly used in Japan for making celadon glazes.  The chemical analyses for Issu wood  (see list by Linda Arbuckle below) are:

    SiO2 Al2O3 TiO2 Fe2O3 CaO MgO K2O Na2O MnO P2O5
    Herbert Sanders, The World of Japanese Ceramics 34.6 4.38 0.49 47.71 5.99 2.51 0.06 0.33 3.93
    Cardew 16.19 4.16 0.92 36.68 6.6 1 0.2 0.48 0.92
    J.B.E. Patterson (via Leach, A Potter’s Book) 71.96 0.63 0.28 15.95 1.57 0.84 0.42

    As you can see, there’s a huge difference between these three analyses, it’s difficult to know if any of them are to be trusted.  So I checked Grebanier’s Chinese Stoneware Glazes and was surprised to find that he had come across the exact same problem (Chapter 13, Synthetic Wood Ash).  Grebanier seems to have abandoned hope of finding an Issu ash substitute, but I went ahead with Sanders’ analysis as it seemed more trustworthy.

    (Actually, perhaps it’s not that Sanders’ analysis is more trustworthy as much as the fact that it’s more interesting to me.)

    I calculated two recipes, one using only Whiting and one minimizing the amount of Whiting by using Wollastonite (without adding too much Silica) and replacing Magnesium Carbonate with Dolomite (in order to provide MgO as well as CaO).

    Recipe 1 (Whiting):

    • Whiting 53.36
    • Custer Feldspar 13.97
    • Silica 13.76
    • Magnesium Carb 9.72
    • Bone Ash 6.63
    • New Zealand Kaolin 2.03
    • Iron 0.31
    • Manganese Dioxide 0.23
    • Total: 100.01

    Recipe 2 (Minimize Whiting):

    • Whiting 21.35
    • Wollastonite 29.86
    • Dolomite 23.14
    • Custer Feldspar 15.46
    • Bone Ash 7.34
    • New Zealand Kaolin 2.25
    • Iron 0.35
    • Manganese Dioxide 0.26
    • Total: 100.01

    Ash Glazes Resources

    Ash Glazes by Robert Tichane.

    The Complete Guide to High Fire Glazes by John Britt.  Besides being my favorite introduction book on glazes, there is a section on ash and synthetic ash glazes.

    Chinese Stoneware Glazes by Joseph Grebanier.  Joseph uses ash in many of his glazes in order to re-create ancient Chinese glazes.

    Ash Glazes by Phil Rogers.  I have not yet read this book, but the reviews are good and the book preview on Google Books looks promising.

    Ash Glaze on the Digitalfire.com website.  Also information on wood ash, hardwood ash, softwood ash, rice straw ash,  and rice husk ash.

    Nigel Wood’s Chinese Ceramics and Science and Civilisation in China: Volume 5, Chemistry and Chemical Technology, Part 12, Ceramic Technology both contain a wealth of information of the role of wood and plant ash in the development of Chinese glazes, including chemical analyses of ashes and comparisons with glaze compositions.

    Some ash glaze recipes can be found on Rick’s Bricks and Tom Turner’s website.

    Chemical Analyses of Various Ashes

    The following information is from a Linda Arbuckle handout, GlazeChem Materials.

    Bamboo ash

    % 4.8 K2O 0.3 CaO 86.4 SiO2 0.4 Fe2O3 8.1 LOI

    Bamboo ash supplies several oxides, especially SiO2.

    Analyses:

    Cardew:

    % 4.8 K2O 0.3 CaO 86.4 SiO2 0.4 Fe2O3 8.1 LOI

    (‘Bamboo sugar’, Java) (Bourry, 1st English edition, 1901)

    Barley straw ash

    % 5 Na2O 22 K2O 3 MgO 8 CaO 57 SiO2 5 P2O5

    Barley straw ash supplies several oxides, especially SiO2 and K2O.

    Analyses:

    Hamer & Hamer:

    % 5 Na2O 22 K2O 3 MgO 8 CaO 57 SiO2 5 P2O5

    Beech ash

    % 8.34 Na2O 24.29 K2O 8.20 MgO 42.00 CaO 3.01 SiO2 6.2 P2O5 0.62 Fe2O3 4.52 MnO 2.10 SO3 0.72 Cl

    Beech ash supplies several oxides, especially CaO and K2O.

    Analyses:

    Rogers:

    % 8.34 Na2O 24.29 K2O 8.20 MgO 42.00 CaO 3.01 SiO2 6.2 P2O5 0.62 Fe2O3 4.52 MnO 2.10 SO3 0.72 Cl

    Rogers (appendix):

    % 4.0 Na2O 16.5 K2O 10.9 MgO 55.5 CaO 5.45 SiO2 5.45 P2O5 1.0 Fe2O3

    Birch ash

    % 9 Na2O 22.6 K2O 14.3 MgO 29.6 CaO 11.5 SiO2 7.9 P2O5 1.3 Fe2O3 0.4 MnO 3.4 LOI

    Birch ash supplies several oxides, especially CaO and K2O.

    Analyses:

    Conrad:

    % 9 Na2O 22.6 K2O 14.3 MgO 29.6 CaO 11.5 SiO2 7.9 P2O5 1.3 Fe2O3 0.4 MnO

    Rogers (appendix):

    % 7.69 Na2O 12.53 K2O 7.69 MgO 57.5 CaO 3.84 SiO2 7.69 P2O5 1.0 Fe2O3

    Hamer & Hamer:

    % 9 Na2O 18 K2O 11 MgO 45 CaO 4 Al2O3 8 SiO2 4 P2O5 1 Fe2O3

    Cedar ash

    % 3.7 Na2O 4.3 K2O 6 MgO 44.2 CaO 0.52 Al2O3 24.28 SiO2 10.6 P2O5 1.01 Fe2O3 0.3 MnO 5.09 LOI

    Cedar ash supplies several oxides, especially CaO and SiO2.

    Analyses:

    Conrad:

    % 3.7 Na2O 4.3 K2O 6 MgO 44.2 CaO 0.52 Al2O3 24.28 SiO2 10.6 P2O5 1.01 Fe2O3 0.3 MnO

    Common ash

    % 2.33 Na2O 3.91 K2O 3.3 MgO 22.42 CaO 8.91 Al2O3 30.99 SiO2 1.91 P2O5 3.04 Fe2O3 1.26 MnO 21.44 LOI

    Common ash supplies several oxides, especially SiO2 and CaO.

    Analyses:

    Sanders:

    % 2.33 Na2O 3.91 K2O 3.3 MgO 22.42 CaO 8.91 Al2O3 30.99 SiO2 1.91 P2O5 3.04 Fe2O3 1.26 MnO 21.44 LOI

    Desert plant ash

    % 28.0 Na2O 5.5 K2O 0.5 MgO 21.1 CaO 1.8 P2O5 34.0 CO2

    Desert plant ash supplies several oxides, especially Na2O and CaO.

    Analyses:

    Tichane (TCB): (adds to 91%)

    % 28.0 Na2O 5.5 K2O 0.5 MgO 21.1 CaO 1.8 P2O5 34.0 CO2

    Elder ash

    % 2 Na2O 17 K2O 16 MgO 38 CaO 14 SiO2 13 P2O5

    Elder ash supplies several oxides, especially CaO.

    Analyses:

    Hamer & Hamer:

    % 2 Na2O 17 K2O 16 MgO 38 CaO 14 SiO2 13 P2O5

    Fern ash

    % 0.56 Na2O 4.81 K2O 7.44 MgO 8.59 CaO 19.32 Al2O3 55.02 SiO2 0.3 TiO2 0.92 P2O5 1.67 Fe2O3 1.36 MnO

    Fern ash supplies several oxides, especially SiO2 and Al2O3.

    Analyses:

    Rogers (appendix):

    % 0.56 Na2O 4.81 K2O 7.44 MgO 8.59 CaO 19.32 Al2O3 55.02 SiO2 0.3 TiO2 0.92 P2O5 1.67 Fe2O3 1.36 MnO

    Hamer & Hamer: (Bracken and fern)

    % 3 Na2O 26 K2O 8 MgO 12 CaO 10 Al2O3 33 SiO2 6 P2O5 1 Fe2O3 1 MnO

    Grass ash

    0.2 KNaO 0.3 MgO 0.5 CaO 0.2 Al2O3 2.0 SiO2

    Grass ash supplies several oxides, especially SiO2 and CaO.

    Generic grass ash.

    Green: (weed and grass ash)

    0.2 KNaO 0.3 MgO 0.5 CaO 0.2 Al2O3 2.0 SiO2

    Green: (unwashed lawn clippings, from Leach “A Potter’s Book”)

    0.41 KNaO 0.29 MgO 0.30 CaO 0.27 Al2O3 1.09 SiO2 0.12 P2O5 0.03 Fe2O3

    Green: (washed lawn clippings, from Leach “A Potter’s Book”)

    0.15 KNaO 0.32 MgO 0.53 CaO 0.38 Al2O3 1.52 SiO2 0.15 P2O5 0.05 Fe2O3

    Rogers: (Lawn grass)

    % 6.20 Na2O 6.19 K2O 5.65 MgO 12.88 CaO 16.60 Al2O3 39.64 SiO2 9.00 P2O5 3.44 Fe2O3

    Hamer & Hamer: (Lawn grass)

    % 3 Na2O 5 K2O 5 MgO 10 CaO 11 Al2O3 59 SiO2 5 P2O5 2 Fe2O3

    Mixed hardwood ash

    % 9.12 Na2O 14 K2O 12 MgO 30 CaO 0.1 Al2O3 15.3 SiO2 13.1 P2O5 2.4 Fe2O3 0.1 MnO 3.88 LOI

    Hearth ash

    % 0.55 Na2O 1.49 K2O 5.44 MgO 35.9 CaO 3.69 Al2O3 14.08 SiO2 2.14 P2O5 0.94 Fe2O3 34.32 h3O 0.14 MnO

    Hearth ash supplies several oxides, especially CaO and SiO2.

    Analyses:

    Cardew:

    % 0.55 Na2O 1.49 K2O 5.44 MgO 35.9 CaO 3.69 Al2O3 14.08 SiO2 2.14 P2O5 0.94 Fe2O3 34.32 h3O 0.14 MnO

    (Hearth ash (‘Dobai’), Japan (E. Kato, Interceram, 2 (1962), 110).)

    Heather ash

    % 9 Na2O 12 K2O 10 MgO 21 CaO 41 SiO2 5 P2O5 2 Fe2O3

    Heather ash supplies several oxides, especially SiO2 and CaO.

    Analyses:

    Hamer & Hamer:

    % 9 Na2O 12 K2O 10 MgO 21 CaO 41 SiO2 5 P2O5 2 Fe2O3

    Issu-wood ash

    % 0.06 Na2O 2.51 K2O 5.99 MgO 47.71 CaO 4.38 Al2O3 34.6 SiO2 3.93 P2O5 0.49 Fe2O3 0.33 MnO

    Isu-wood ash supplies several oxides, especially CaO and SiO2.  Issu (Distylium racemosum) is the source of a very popular wood ash in Japan. Note the incredible variations in the analyses.

    Analyses:

    Sanders:

    % 0.06 Na2O 2.51 K2O 5.99 MgO 47.71 CaO 4.38 Al2O3 34.6 SiO2 3.93 P2O5 0.49 Fe2O3 0.33 MnO

    Cardew:

    % 0.2 Na2O 1 K2O 6.6 MgO 36.68 CaO 4.16 Al2O3 16.19 SiO2 3.67 P2O5 0.92 Fe2O3 30.08 h3O 0.8 SO3 0.48 MnO

    (Isu Ash from Hagi, Japan (E. Kato, Interceram, 2 (1962), 110).)

    Leach (“A Potter’s Book”):

    % 0.84 K2O 1.57 MgO 15.95 CaO 0.63 Al2O3 71.96 SiO2 0.42 P2O5 0.28 Fe2O3 8.29 LOI

    (from work done by J.B.E. Patterson)

    Ivy ash

    % 20 Na2O 26 K2O 8 MgO 25 CaO 12 SiO2 6 P2O5 3 Fe2O3

    Ivy ash supplies several oxides, especially CaO, K2O, and Na2O.

    Analyses:

    Hamer & Hamer:

    % 20 Na2O 26 K2O 8 MgO 25 CaO 12 SiO2 6 P2O5 3 Fe2O3

    Larch wood ash

    % 9 Na2O 21 K2O 8 MgO 27 CaO 1 Al2O3 11 SiO2 8 P2O5 4 Fe2O3 11 MnO

    Larch wood ash supplies several oxides, especially CaO, K2O, SiO2, and MnO.

    Analyses:

    Hamer & Hamer:

    % 9 Na2O 21 K2O 8 MgO 27 CaO 1 Al2O3 11 SiO2 8 P2O5 4 Fe2O3 11 MnO

    Mahogany ash

    % 10.98 Na2O 9.49 K2O 4.39 MgO 9.49 CaO 3.81 Al2O3 51.51 SiO2 2.08 P2O5 4.53 Fe2O3 3.72 LOI

    Mahogany ash supplies several oxides, especially SiO2.

    Analyses:

    Cardew:

    % 10.98 Na2O 9.49 K2O 4.39 MgO 9.49 CaO 3.81 Al2O3 51.51 SiO2 2.08 P2O5 4.53 Fe2O3

    (Australian white mahogany) (Forestry Commission of New South Wales, 1956)

    Maple ash

    % 6.04 Na2O 6.2 K2O 12.05 MgO 27.5 CaO 0.9 Al2O3 13.8 SiO2 8.1 P2O5 2.5 Fe2O3 0.5 MnO 22.41 LOI

    Maple ash supplies several oxides, especially CaO.

    Analyses:

    Conrad:

    % 6.04 Na2O 6.2 K2O 12.05 MgO 27.5 CaO 0.9 Al2O3 13.8 SiO2 8.1 P2O5 2.5 Fe2O3 0.5 MnO

    Meadow hay ash

    % 7.0 Na2O 25.67 K2O 5.0 MgO 11.56 CaO 29.57 SiO2 6.2 P2O5 1.0 Fe2O3

    Meadow hay ash supplies several oxides, especially SiO2 and K2O.

    Analyses:

    Rogers (appendix):

    % 7.0 Na2O 25.67 K2O 5.0 MgO 11.56 CaO 29.57 SiO2 6.2 P2O5 1.0 Fe2O3

    Hamer & Hamer: (Meadow grass)

    % 4 Na2O 15 K2O 5 MgO 10 CaO 3 Al2O3 58 SiO2 4 P2O5 1 Fe2O3

    Mixed wood ash

    0.125 Na2O 0.266 K2O 0.187 MgO 0.422 CaO 0.016 Al2O3 0.375 SiO2 0.109 P2O5 0.062 Fe2O3

     

    Oak ash

    % 9.12 Na2O 14 K2O 12 MgO 30 CaO 0.1 Al2O3 15.3 SiO2 13.1 P2O5 2.4 Fe2O3 0.1 MnO 3.88 LOI

    Oak ash supplies several oxides, especially CaO.

    Analyses:

    Conrad:

    % 9.12 Na2O 14 K2O 12 MgO 30 CaO 0.1 Al2O3 15.3 SiO2 13.1 P2O5 2.4 Fe2O3 0.1 MnO

    Tichane (TCB):

    % 3.9 Na2O 9.5 K2O 3.9 MgO 72.5 CaO 2.0 SiO2 5.8 P2O5

    Rogers: (English oak)

    % 9.12 Na2O 14.00 K2O 12.01 MgO 30.02 CaO 0.13 Al2O3 15.30 SiO2 13.8 P2O5 2.40 Fe2O3 0.10 MnO 0.05 CuO 2.61 SO3 1.18 Cl

    Rogers (appendix): (China)

    % 1.47 Na2O 5.77 K2O 4.09 MgO 23.54 CaO 15.11 Al2O3 39.81 SiO2 2.3 P2O5 3.58 Fe2O3 4.32 MnO

    Rogers (appendix): (Japan)

    % 1.52 Na2O 5.68 K2O 4.14 MgO 23.69 CaO 16.34 Al2O3 39.62 SiO2 2.62 P2O5 3.83 Fe2O3 1.01 MnO

    Hamer & Hamer:

    % 6 Na2O 11 K2O 9 MgO 51 CaO 1 Al2O3 10 SiO2 10 P2O5 1 Fe2O3 1 MnO

    Straw ash

    0.4 KNaO 0.2 MgO 0.4 CaO 2.7 SiO2 0.1 P2O5

    Straw ash supplies several oxides, especially SiO2.  Generic straw ash.

    Analyses:

    Green: (straw ash from cereal crops)

    0.4 KNaO 0.2 MgO 0.4 CaO 2.7 SiO2 0.1 P2O5

    Tallowwood ash

    % 6.84 Na2O 2.41 K2O 25.58 MgO 52.15 CaO 1.09 Al2O3 8.96 SiO2 0.4 P2O5 1.93 SO3 0.38 Cl2 0.18 MnO

    Tallowwood ash supplies several oxides, especially CaO and MgO.

    Analyses:

    Cardew:

    % 6.84 Na2O 2.41 K2O 25.58 MgO 52.15 CaO 1.09 Al2O3 8.96 SiO2 0.4 P2O5 1.93 SO3 0.38 Cl2 0.18 MnO

    (Eucalyptus microscorys III (Tallowwood) Forestry Commission of New South Wales, 1956)

    Thatching grass ash

    % 0.22 Na2O 2.55 K2O 3.67 MgO 6.14 CaO 5.42 Al2O3 76.96 SiO2 1.58 P2O5 0.22 TiO2 1.06 Fe2O3 0.15 SO3 0.67 MnO 1.4 LOI

    Thatching grass ash supplies several oxides, especially SiO2.

    Analyses:

    Cardew:

    % 0.22 Na2O 2.55 K2O 3.67 MgO 6.14 CaO 5.42 Al2O3 76.96 SiO2 1.58 P2O5 0.22 TiO2 1.06 Fe2O3 0.15 SO3 0.67 MnO 1.4 LOI

    (Abuja, Nigeria. Wahsed and calcined at 900C) (Overseas Geological Surveys, London, 1966)

    Turpentine ash

    % 4.08 Na2O 1.2 K2O 1.03 MgO 1.88 CaO 1.26 Al2O3 89.74 SiO2 0.39 P2O5 0.42 LOI

    Turpentine ash supplies several oxides, especially SiO2.

    Analyses:

    Cardew:

    % 4.08 Na2O 1.2 K2O 1.03 MgO 1.88 CaO 1.26 Al2O3 89.74 SiO2 0.39 P2O5

    (Australian turpentine) (Forestry Commission of New South Wales, 1956)

    Wheat straw ash

    % 2.8 Na2O 11.5 K2O 2.5 MgO 6.1 CaO 66.2 SiO2 5.4 P2O5 2.8 SO3 3.8 S

    Wheat straw ash supplies several oxides, especially SiO2 and K2O.

    Analyses:

    Cardew:

    % 2.8 Na2O 11.5 K2O 2.5 MgO 6.1 CaO 66.2 SiO2 5.4 P2O5 2.8 SO3 3.8 S

    (Air dried) (B.C.S., (1959), 59P)

    Green:

    0.67 K2O 0.14 MgO 0.19 CaO 0.71 Al2O3 4.95 SiO2 0.10 P2O5

    Tichane (TCB):

    % 2.8 Na2O 11.5 K2O 2.5 MgO 6.1 CaO 66.0 SiO2 5.4 P2O5 2.8 LOI

    Rogers:

    % 1.4 Na2O 13.6 K2O 2.5 MgO 5.8 CaO 67.5 SiO2 4.8 P2O5 0.6 Fe2O3

    Hamer & Hamer:

    % 2 Na2O 13 K2O 4 MgO 6 CaO 70 SiO2 5 P2O5

    Willow ash

    % 2.50 Na2O 49.80 K2O 8.26 MgO 20.21 CaO 0.05 Al2O3 4.44 SiO2 10.00 P2O5 1.25 Fe2O3 0.18 MnO 1.22 SO3 0.08 Cl

    Willow ash supplies several oxides, especially K2O, CaO, and P2O5.

    Analyses:

    Rogers:

    % 2.50 Na2O 49.80 K2O 8.26 MgO 20.21 CaO 0.05 Al2O3 4.44 SiO2 10.00 P2O5 1.25 Fe2O3 0.18 MnO

    1.22 SO3 0.08 Cl

    Hamer & Hamer:

    % 3 Na2O 51 K2O 9 MgO 21 CaO 5 SiO2 10 P2O5 1 Fe2O3

    Ash wood ash

    0.125 Na2O 0.266 K2O 0.187 MgO 0.422 CaO 0.016 Al2O3 0.375 SiO2 0.109 P2O5 0.062 Fe2O3

    Ash wood ash supplies several oxides, especially CaO and SiO2.

    Analyses:

    Hamer & Hamer:

    % 8 Na2O 17 K2O 12 MgO 27 CaO 1 Al2O3 24 SiO2 7 P2O5 4 Fe2O3

  • Jingdezhen

    Cat nap