iandol on wed 4 sep 02
Dear Don Hunt,
You ask ".."liquid in liquid separated glaze" mean anything to anyone, =
or is it like an artist statement, meaning everything to everyone."
This is a term for a form of Phase separation which can happen when some =
glazes are cooled slowly enough for some form of chemical reaction and =
segregation to happen but fast enough for both of the liquids to change =
into glass without crystallisation. It seems, and you will have to check =
with someone like Dr. Pamela Vandiver on this, that there is a degree of =
immiscibility. Perhaps this happens when phosphate salts such as Bone =
Ash or Plant Ash fully dissolve into a silicate melt. When this melt =
cools, two glasses, one based on Silica tetrahedra and the other on =
Phosphorus Pentoxide tetrahedra, segregate.
I suspect this is a very complex chemistry.
Best regards,
Ivor Lewis. Redhill, South Australia
Alistair Gillies on thu 5 sep 02
Hi,
Sounds very interesting. Do you, or anyone, know of any pictures?
BTW This sort of glaze [and others such as crystaline] was what I was
referring to in my post about cooling. At high temps the temperature
drop is about the requirements of the glaze rather than the clay.
All the best,
Alistair
Shropshire, England
>
>This is a term for a form of Phase separation which can happen when some glazes
>are cooled slowly enough for some form of chemical reaction and segregation to
>happen but fast enough for both of the liquids to change into glass without
>crystallisation. It seems, and you will have to check with someone like Dr.
>Pamela Vandiver on this, that there is a degree of immiscibility. Perhaps this
>happens when phosphate salts such as Bone Ash or Plant Ash fully dissolve into a
>silicate melt. When this melt cools, two glasses, one based on Silica tetrahedra
>and the other on Phosphorus Pentoxide tetrahedra, segregate.
>
>I suspect this is a very complex chemistry.
>
>Best regards,
>
>Ivor Lewis. Redhill, South Australia
Alistair Gillies
AGP Studio
01952 882909
07973 866198
www.agpstudio.co.uk [The builders are still working]
www.allblackedup.co.uk [English Ceilidh Band]
John Kimpton Dellow on fri 6 sep 02
iandol wrote:
>
> Dear Don Hunt,
>
> You ask ".."liquid in liquid separated glaze" mean anything to anyone, or is it like an artist statement, meaning everything to everyone."
There is a good explanition in "Parmelee Ceramic Glazes " under
Liquid-liquid Separation
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