Eleanora Eden on sat 1 feb 97
Hi all,
My books only refer to quartz inversion around 1060F. I always thought
there was also one around 800F. No? Yes? Another reason for slowing
down a kiln around 800F?
TIA
Eleanora
Eleanora Eden 802 869-2003
Paradise Hill
Bellows Falls, VT 05101 eden@maple.sover.net
[the address fga@world.std.com is temporary. My mailbox at
eden@maple.sover.net still works -- do not change address books]
Ron Roy on mon 3 feb 97
>----------------------------Original message----------------------------
>Hi all,
>
>My books only refer to quartz inversion around 1060F. I always thought
>there was also one around 800F. No? Yes? Another reason for slowing
>down a kiln around 800F?
>
>TIA
>
>Eleanora
>
Hi Eleanora,
The temperature you state is accurate for the quartz inversion (1063.4 F =
573C) however there is nothing happening, inversion wise, at 800F (426.6C.)
Cristobalite (another form of crystaline silica) does go through a
reversible inversion at around 200C (392F.) It is more gradual then the
quartz inversion and happens at possible ovenware temperatures. My
information comes from diatometer charts and are reflections of what
actually happens to clays and glazes as they are heated and cooled.
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
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