FLOATING BLUE
Le « Floating Blue » est probablement la plus connue et la plus populaire des glaçures de cône 6. Comme la plupart des autres émaux glassés contenant du Gerstley Borate, elle contient aussi de la Néphéline Syénite, de la Silice et du Kaolin. Les effets bigarrés de surface sont causés par le Rutile au niveau d’environ 4%.
Le terme « floating » peut être dû à deux possibilités.
1-La surface colorée en bleu de cobalt semble flotter sur une couche de verre brun translucide. Cette couche est visible lorsqu’elle devient brune par amincissement sur les rebords de la pièce et les irrégularités et/ou textures de surface.
2-Plus particulièrement, cependant, ce terme s’applique à une couche opalescente, blanche- 'bleu de boron', qui semble souvent flotter sur un fond de bleu de cobalt. Certains auteurs disent que « les couleurs semblent flotter à la surface d’un fond foncé ayant une grande profondeur, rappelant une profonde mare d’eau » .
La chose étonnante au sujet de ce type de glaçure, c’est qu’elle puisse produire des effets bigarrés de surface par six mécanismes différents.
-Sa couleur et son opacité changent considérablement avec l'épaisseur, ainsi elle met en valeur les irrégularités de surface.
-La ' séparation de phase ' dans la matrice translucide fait tourbillonner la couleur comme de petits ruisseaux d'un écoulement de verre plus liquide autour de phases plus visqueuses.
-Les cristaux de titanium dans la matrice la font étinceller.
-Les cristaux de borate de calcium bleus croissent à la surface.
-Les bulles de gaz qui s'échappent créent des flaques (lacs) de verres colorés plus légèrement, entourées par des anneaux plus foncés.
-De petites taches noires sont produites par des particules de fer non dispersées.
Pas surprenant que ce soit une glaçure si populaire auprès des potiers
Tous ceux qui ont utilisé ce type de glaçure témoigneront du fait qu'elle est " inconsistante " et qu’elle a tendance à couler. Il y a un certain nombre de recommandations concernant son utilisation:
- utiliser de l'eau distillée ou basse en minéraux,
- tout tamiser à 80 mailles,
- bien brasser la glaçure avant et pendant son utilisation afin d’empêcher la précipitation du fer,
- appliquer l'épaisseur d'un dix sous (1mm.),
- cuire en oxydation à cône 6 exactement, et refroidir normalement.
A-Voici quelques exemples de ces glaçures de cône 6 en oxydation :
Floating Blue
Néphéline Syénite, 47.3
Gerstley Borate, 27.0
Silice, 20.3
Kaolin, 5.4
Total, 100.0
Rutile, 4.0
Oxyde de Fer Rouge, 2.0
Oxyde de Cobalt, 1.0
De James Chappell
Floating Blue#1
Néphéline Syénite, 41
Gerstley Borate, 7
Fritte Ferro #3134, 13
Silice, 18
Kaolin, 11
Total, 100
Rutile, 4
Oxyde de Fer Rouge, 2
Carbonate de Cobalt, 1.5
De Clayart (Ron Roy)
Floating Blue#2
Néphéline Syénite, 35.5
Gerstley Borate, 8.5
Fritte Ferro #3134, 24.5
Silice, 16
Kaolin, 15.5
Total, 100
Rutile, 4
Oxyde de Fer Rouge, 4
Carbonate de Cobalt, 1.5
De Clayart (Ron Roy)
Floating Blue#3
Néphéline Syénite, 30
Fritte Ferro #3134, 36
Silice, 14
Kaolin, 20
Total, 100
Rutile, 4
Oxyde de Fer Rouge, 2
Carbonate de cobalt, 1.5
De Clayart (Ron Roy)
B-Un exemple pour cône 10 en oxydation :
Floating Blue
Feldspath potassique, 52.0
Gerstley Borate, 11.5
Wollastonite, 9.0
Kaolin, 5.5
Silice, 22.0
Total, 100
Rutile, 4.0
Oxyde de Fer Rouge, 2.0
Oxyde de Cobalt, 1.0
De Clayart (Tom Buck)
C-Quelques exemples de cône 9-10 en réduction :
Floating Blue #1 C9R
Cornawall Stone, 27
Feldspath potassique, 16
Fritte Ferro #3134, 18
Dolomite, 4
Silice, 18.5
Carbonate de calcium, 6
Ball clay, 9
Kaolin, 8
Total, 106.5
Bentonite, 2
*QIT-UGS, 4
*QIT-Ilmenite, 2
Carbonate de cobalt, 0.5
Ceci est une modification du Coyote Blue
publié par Ron Roy sur Clayart (newsgroup).
Floating Blue #2 C9R
Cornwall Stone, 63.8
Gerstley Borate, 14.3
Silice, 7.6
Carbonate de calcium, 7.6
Kaolin, 4.8
Oxyde de zinc (calc.), 1.9
Total, 100
Bentonite, 2
*QIT-UGS, 4.2
*QIT-Ilmenite, 2.0
Carbonate de cobalt, 0.5
Ceci est une modification du Moonlight Blue
de Wayne Conrad publié sur Clayart (newsgroup).
Références :
1-Digitalfire.com, Tony Hansen, Alberta, Canada
http://digitalfire.com/
2-The Potter’s Complete Book of Clay and Glazes, James Chappell.
3-Le newsgroup Clayart pour céramistes.
http://lsv.ceramics.org/archivedata/clayart.html
*QIT-Fer et Titane, une filiale québecoise de Rio Tinto Zinc (Angleterre),
exploite une énorme mine d’ilménite dans le nord-est du Québec.
Le minérai est acheminé par bateau à son usine de Sorel-Tracy
où il est tranformé en différents produits dont l’ilménite et l’UGS.
L’UGS est un rutile synthétique granulaire et la granulométrie
que nous avons utilisée variait de 120 à 140 mailles.
jeudi 10 mai 2007
Text on Floating Blue
Floating Blue
Floating Blue (also called Blue Hare's Fur) is probably the most well known and popular cone 6 pottery glaze. It was popularized by the book The Potter's Complete Book of Clay and Glazes by James Chappell (in the current edition it is on page 210 under the heading "Floating Glazes"). The author calls it "spectacular and extraordinary". In fact, the vase that graces the cover of the book uses this glaze. Like most other popular glossy GB base glazes, this one also uses nepheline syenite, silica and kaolin. Its borate content is about middle-of-the-road compared to the range of recipes that we have studied. Like the Butterscotch glaze, the fired effects produced by this recipe are a testament to the variegating effects that 4% rutile imparts to colored non-opacified boron glazes.
The term 'floating' could refer to two possibilities in our observation: The blue cobalt colored surface appears to float on a translucent brown glass layer. This layer is visible where the color breaks to brownish hues on thinner sections at edges and irregularities in the surface. More likely, however, it refers to a white opalescent 'boron-blue' layer that often appears to float over the cobalt blue background (boron-blue calcium borate crystals form in borate glazes when calcium is present and the glaze is very fluid). This effect can best be amplified by melting a ball of glaze on a tile to get a very thick pool of glass. Cappell says "the colors seem to float on a surface of a darker background of great depth, reminiscent of a deep pool of water".
An amazing thing about this recipe is that it actually has the potential to produce six separate mechanisms of variegation:
· Its color and opacity vary greatly with thickness so it highlights irregularities in the surface.
· 'Phase separation' in the translucent matrix makes the color 'swirl' as small rivulets of more fluid glass flow around more viscous phases.
· Titanium crystals in the matrix make it sparkle.
· Calcium-borate boron-blue crystals grow on the surface.
· Bubbles of escaping gases create pools of lighter colored glass surrounded by darker rings.
· Small black speckles are produced by unground particles of iron.
No wonder this is such a popular glaze among potters!
Anyone who has used this glaze will testify to the fact that it is "fickle" as Chappell notes. He makes a number of recommendations on using this recipe:
-use distilled or low mineral water,
-force all material through an 80 mesh screen,
-stir thoroughly before and during use to prevent settling out of the iron content,
-apply the thickness of a dime (1mm.),
-fire to cone 6 oxidation exactly, and cool normally.
A-Here are a few examples for cone 6 oxidation :
Floating Blue
Nepheline Syenite, 47.3
Gerstley Borate, 27.0
Silica, 20.3
Kaolin, 5.4
Totals, 100.0
Rutile, 4.0
Red Iron Oxide, 2.0
Cobalt Oxide, 1.0
from James Chappell
Floating Blue#1
Nepheline Syenite, 41
Gerstley Borate, 17
Ferro Frit #3134, 13
Silica, 18
Kaolin, 11
Totals, 100
Rutile, 4
Red Iron Oxide, 2
Cobalt Carbonate, 1.5
From Clayart (Ron Roy)
Floating Blue#2
Nepheline Syenite, 35.5
Gerstley Borate, 8.5
Ferro Frit #3134, 24.5
Silica, 16
Kaolin, 15.5
Totals, 100
Rutile, 4
Red Iron Oxide, 4
Cobalt Carbonate, 1.5
From Clayart (Ron Roy)
Floating Blue#3
Nepheline Syenite, 30
Ferro Frit #3134, 36
Silica, 14
Kaolin, 20
Totals, 100
Rutile, 4
Red Iron Oxide, 2
Cobalt Carbonate, 1.5
From Clayart (Ron Roy)
B-One example for cone 10 oxidation :
Floating Blue
Potassium Spar, 52.0
Gerstley Borate, 11.5
Wollastonite, 9.0
Kaolin, 5.5
Silica, 22.0
Totals, 100
Rutile, 4.0
Red Iron Oxide, 2.0
Cobalt Oxide, 1.0
From Clayart (Tom Buck)
C-A few examples for cone 9-10 reduction :
Floating Blue #1 C9R
Cornwall Stone, 27
Potassium Spar, 16
Ferro Frit #3134, 18
Dolomite, 4
Silica, 18.5
Whiting, 6
Ball clay, 9
Kaolin, 8
Totals, 106.5
Bentonite, 2
*QIT-UGS, 4
*QIT-Ilmenite, 2
Cobalt carbonate, 0.5
This is a modified version of Ron Roy’s Coyote Blue
published on Clayart (newsgroup).
Floating Blue #2 C9R
Cornwall Stone, 63.8
Gerstley Borate, 14.3
Silica, 7.6
Whiting, 7.6
Kaolin, 4.8
Zinc Oxid (calc.), 1.9
Total, 100
Bentonite, 2
*QIT-UGS, 4.2
*QIT-Ilmenite, 2.0
Cobalt carbonate, 0.5
This is a modified version of Wayne Conrad’s Moonlight Blue
published on Clayart (newsgroup).
References :
1-Digitalfire.com, Tony Hansen, Alberta, Canada
http://digitalfire.com/
2-The Potter’s Complete Book of Clay and Glazes, James Chappell.
3-Clayart, a newsgroup for ceramicists.
http://lsv.ceramics.org/archivedata/clayart.html
*QIT-Fer et Titane, a subsidiary of Rio Tinto Zinc (United Kingdom),
operates a huge ilmenite mine in northeastern Québec.
The ore is shipped to their Sorel-Tracy facilities where it is processed to
many products among which ilmenite and UGS.
UGS is a granular synthetic rutile and the particle size used varied
from from 120 to 140 mesh.
Floating Blue (also called Blue Hare's Fur) is probably the most well known and popular cone 6 pottery glaze. It was popularized by the book The Potter's Complete Book of Clay and Glazes by James Chappell (in the current edition it is on page 210 under the heading "Floating Glazes"). The author calls it "spectacular and extraordinary". In fact, the vase that graces the cover of the book uses this glaze. Like most other popular glossy GB base glazes, this one also uses nepheline syenite, silica and kaolin. Its borate content is about middle-of-the-road compared to the range of recipes that we have studied. Like the Butterscotch glaze, the fired effects produced by this recipe are a testament to the variegating effects that 4% rutile imparts to colored non-opacified boron glazes.
The term 'floating' could refer to two possibilities in our observation: The blue cobalt colored surface appears to float on a translucent brown glass layer. This layer is visible where the color breaks to brownish hues on thinner sections at edges and irregularities in the surface. More likely, however, it refers to a white opalescent 'boron-blue' layer that often appears to float over the cobalt blue background (boron-blue calcium borate crystals form in borate glazes when calcium is present and the glaze is very fluid). This effect can best be amplified by melting a ball of glaze on a tile to get a very thick pool of glass. Cappell says "the colors seem to float on a surface of a darker background of great depth, reminiscent of a deep pool of water".
An amazing thing about this recipe is that it actually has the potential to produce six separate mechanisms of variegation:
· Its color and opacity vary greatly with thickness so it highlights irregularities in the surface.
· 'Phase separation' in the translucent matrix makes the color 'swirl' as small rivulets of more fluid glass flow around more viscous phases.
· Titanium crystals in the matrix make it sparkle.
· Calcium-borate boron-blue crystals grow on the surface.
· Bubbles of escaping gases create pools of lighter colored glass surrounded by darker rings.
· Small black speckles are produced by unground particles of iron.
No wonder this is such a popular glaze among potters!
Anyone who has used this glaze will testify to the fact that it is "fickle" as Chappell notes. He makes a number of recommendations on using this recipe:
-use distilled or low mineral water,
-force all material through an 80 mesh screen,
-stir thoroughly before and during use to prevent settling out of the iron content,
-apply the thickness of a dime (1mm.),
-fire to cone 6 oxidation exactly, and cool normally.
A-Here are a few examples for cone 6 oxidation :
Floating Blue
Nepheline Syenite, 47.3
Gerstley Borate, 27.0
Silica, 20.3
Kaolin, 5.4
Totals, 100.0
Rutile, 4.0
Red Iron Oxide, 2.0
Cobalt Oxide, 1.0
from James Chappell
Floating Blue#1
Nepheline Syenite, 41
Gerstley Borate, 17
Ferro Frit #3134, 13
Silica, 18
Kaolin, 11
Totals, 100
Rutile, 4
Red Iron Oxide, 2
Cobalt Carbonate, 1.5
From Clayart (Ron Roy)
Floating Blue#2
Nepheline Syenite, 35.5
Gerstley Borate, 8.5
Ferro Frit #3134, 24.5
Silica, 16
Kaolin, 15.5
Totals, 100
Rutile, 4
Red Iron Oxide, 4
Cobalt Carbonate, 1.5
From Clayart (Ron Roy)
Floating Blue#3
Nepheline Syenite, 30
Ferro Frit #3134, 36
Silica, 14
Kaolin, 20
Totals, 100
Rutile, 4
Red Iron Oxide, 2
Cobalt Carbonate, 1.5
From Clayart (Ron Roy)
B-One example for cone 10 oxidation :
Floating Blue
Potassium Spar, 52.0
Gerstley Borate, 11.5
Wollastonite, 9.0
Kaolin, 5.5
Silica, 22.0
Totals, 100
Rutile, 4.0
Red Iron Oxide, 2.0
Cobalt Oxide, 1.0
From Clayart (Tom Buck)
C-A few examples for cone 9-10 reduction :
Floating Blue #1 C9R
Cornwall Stone, 27
Potassium Spar, 16
Ferro Frit #3134, 18
Dolomite, 4
Silica, 18.5
Whiting, 6
Ball clay, 9
Kaolin, 8
Totals, 106.5
Bentonite, 2
*QIT-UGS, 4
*QIT-Ilmenite, 2
Cobalt carbonate, 0.5
This is a modified version of Ron Roy’s Coyote Blue
published on Clayart (newsgroup).
Floating Blue #2 C9R
Cornwall Stone, 63.8
Gerstley Borate, 14.3
Silica, 7.6
Whiting, 7.6
Kaolin, 4.8
Zinc Oxid (calc.), 1.9
Total, 100
Bentonite, 2
*QIT-UGS, 4.2
*QIT-Ilmenite, 2.0
Cobalt carbonate, 0.5
This is a modified version of Wayne Conrad’s Moonlight Blue
published on Clayart (newsgroup).
References :
1-Digitalfire.com, Tony Hansen, Alberta, Canada
http://digitalfire.com/
2-The Potter’s Complete Book of Clay and Glazes, James Chappell.
3-Clayart, a newsgroup for ceramicists.
http://lsv.ceramics.org/archivedata/clayart.html
*QIT-Fer et Titane, a subsidiary of Rio Tinto Zinc (United Kingdom),
operates a huge ilmenite mine in northeastern Québec.
The ore is shipped to their Sorel-Tracy facilities where it is processed to
many products among which ilmenite and UGS.
UGS is a granular synthetic rutile and the particle size used varied
from from 120 to 140 mesh.
mardi 8 mai 2007
C/9½ Redux Ash Floating Blue--C/9½ R Floating Blue Cendré
Nepheline/Syenite, 28
Frit #3134, 7.5
Gerstley Borate, 7.5
Washed Hardwood Ash, 19
Kaolin, 14
Silica, 28
Bentonite, 2
Rutile, 5
Ilmenite, 2
Cobalt carbonate, 1.5
C/9½ Redux Ash Floating Blue--C/9½ R Floating Blue Cendré
C/9½ Redux Ash Floating Blue/
C/9½ R Floating Blue Cendré
Silica, 15
Kaolin, 15
Custer Spar, 50
Hardwood Ash (washed), 20
Total, 100
Bentonite, 2
Rutile, 4.5
Cobalt carbonate, 4.0
Funnily, it does not contain boron.
Bizarrement, elle ne contient pas de bore.
C/9½ R Floating Blue Cendré
Silica, 15
Kaolin, 15
Custer Spar, 50
Hardwood Ash (washed), 20
Total, 100
Bentonite, 2
Rutile, 4.5
Cobalt carbonate, 4.0
Funnily, it does not contain boron.
Bizarrement, elle ne contient pas de bore.
C/9½ Redux Floating Blue--C/9½ R Floating Blue
C/9½ Redux Floating Blue
Bone ash, 4
Silica, 25
Gerstley borate, 7
Dolomite, 3
Nepheline/Syenite, 40
Whiting, 10
Zinc oxide, 5
Total, 94
Bentonite, 3
QIT-Ilmenite, 2
QIT-UGS Rutile, 4
Cobalt carbonate, 0.75
Bone ash, 4
Silica, 25
Gerstley borate, 7
Dolomite, 3
Nepheline/Syenite, 40
Whiting, 10
Zinc oxide, 5
Total, 94
Bentonite, 3
QIT-Ilmenite, 2
QIT-UGS Rutile, 4
Cobalt carbonate, 0.75
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