Monthly Tech-Tip from Tony Hansen SignUp

No tracking! No ads!

Body Color | Body Maturity | Body Plasticity | Body Thermal Expansion | Crystal Glaze Variations | Deflocculant | Glaze Color | Glaze Crystallization | Glaze Matteness | Glaze Opacifier | Glaze Surface Texture | Glaze Suspender |

Glaze Variegation Property

In contrast to the typical homogeneous surfaces of sanitaryware and most table ware, reactive glazes exhibit discontinuities in texture, matteness, reflectivity, color, etc that are called variegation. These variations are normally caused by crystallization, speckling and rivulets and opacity variations associated with phase separation. By understanding these mechanisms it is possible to produce glazes of more interesting appearance.

Mechanisms

Oxides ZrO
Oxides Li2O
Oxides CaO
Materials Iron Oxide Red
Oxides P2O5
Materials Ilmenite
Materials Rutile
Materials Iron Pyrite
Materials Granular Ilmenite
Materials Granular Rutile
Materials Tin Oxide
Materials Titanium Dioxide
Oxides TiO2

Variegation and phase separation with about 5% rutile


The glaze is a dolomite matte fired to cone 10R. High fire reduction is among the best processes to exploit the variegating magic of rutile.

Links

Glossary Phase Separation
Phase separation is a phenomenon that occurs in transparent ceramic glazes. Discontinuities in the internal glass matrix affect clarity and color.
Glossary Crystalline glazes
A type of ceramic glaze made by potters. Giant multicolored crystals grown on a super gloss low alumina glaze by controlling multiple holds and soaks during cooling
Glossary Crystallization
Ceramic glazes form crystals on cooling if the chemistry is right and the rate of cool is slow enough to permit molecular movement to the preferred orientation.
Glossary Opacifier
Glaze opacity refers to the degree to which it is opaque. Opacifiers are powders added to transparent ceramic glazes to make them opaque.
Glossary Reactive Glazes
In ceramics, reactive glazes have variegated surfaces that are a product of more melt fluidity and the presence of opacifiers, crystallizers and phase changers.
Glossary Reduction Firing
A method of firing stoneware where the kiln air intakes and burners are set to restrict or eliminate oxygen in the kiln such that metallic oxides convert to their reduced metallic state.
Glossary Dolomite Matte
Dolomite matte glazes have the potential to be very silky and pleasant to the touch, while at the same time being hard, durable and non-crazed (if they are formulated correctly).
Glossary Mechanism
Identifying the mechanism of a ceramic glaze recipe is the key to moving adjusting it, fixing it, reverse engineering it, even avoiding it!
Glossary Variegation
Ceramic glaze variegation refers to its visual character. This is an overview of the various mechanisms to make glazes dance with color, crystals, highlights, speckles, rivulets, etc.
Oxides MgO - Magnesium Oxide, Magnesia
By Tony Hansen
Follow me on

Got a Question?

Buy me a coffee and we can talk

 



https://digitalfire.com, All Rights Reserved
Privacy Policy