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nceca 2007/ now: cones & antiquity

updated thu 25 may 06

 

Snail Scott on sat 20 may 06


At 05:31 PM 5/19/2006 +0930, you wrote:
>Dear Elizabeth Priddy
>You say<< ...The reason the ancients used cone ten is because if you fire
anything hot enough it will melt...>>
>Agreement with your science, but how ancient are "Cones" ? I thought they
had been around for about a hundred and twenty years. Before that there
were various sorts of "Bars" and "Rings", products of the Industrial
revolution. Prior to that it was draw trials...


I think we could agree to equate terms like "^10"
with "heat-work which is equivalent to what is
indicated by an Orton cone ten". OK?

I would never presume that Elizabeth is postulating
the use of pyrometric cones in antiquity, and I find
her conventional shorthand terminology (shared by many)
to be perfectly acceptable. I don't quibble if someone
says they "fired to ^8" using a pyrometer in a computer-
controlled firing; I am willing to accept that the kiln
was fired to something approximating the heat-work
equivalent of ^8. Stating temperature (or rather, heat-
work) in cone-equivalent terms is more common than not
in the U.S., regardless of the means of determining it:
cones, pyrometer, draw trials, color judgement, or
whatever.

While I recognize that firing temperatures are a more
common referent in the UK, Australia, and elsewhere,
this usage is not really more accurate for our purposes,
since such numbers convey no indication of the heat-work
actually done during the firing, but only the temperature
reached. In fact, even when the actual firing was done
with cones and not a pyrometer, British practice often
uses temperature as the sole stated referent, but we
accept this as referring to some conventional amount of
heat-work done at that temperature over a presumed normal
firing length.

May we simply take both usages (cone equivalents AND
temperature equivalents of heat-work) to be conventional
descriptive usages: informative, but not intended to be
a literal description of the firing standard used?

Honestly, Ivor, did you really assume that Elizabeth
thought cones were used in antiquity? I doubt it!

Aiming for accuracy in terminology is a laudable goal,
but many conventional usages (like defining heat-work
in terms of cones or temperature) simply seem convenient
and clear, and not misleading.

-Snail

Ivor and Olive Lewis on mon 22 may 06


Dear Snail Scott,=20

I read the statement as it appeared to me, as a simple statement of fact =
and not as a metaphor.

If you wish to interpret it as a metaphor for "heat-work which is =
equivalent to what is
indicated by an Orton cone ten" OK.

I do agree with Elizabeth Priddy that if you can raise the temperature =
of anything high enough there will come a point at which it will melt.

As an aside, how much Heat is necessary to cause an Orton # Ten Cone to =
melt?

Best regards,

Ivor Lewis.
Redhill,
South Australia.

Earl Brunner on mon 22 may 06


Hummmm, diamonds came to mind, do they "melt" when
heated high enough?

Earl Brunner
Las Vegas, NV
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On
Behalf Of Ivor and Olive Lewis
Sent: Sunday, May 21, 2006 11:31 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: NCECA 2007/ now: cones & antiquity


I do agree with Elizabeth Priddy that if you can raise
the temperature of anything high enough there will come
a point at which it will melt.


Best regards,

Ivor Lewis.
Redhill,
South Australia.

W J Seidl on tue 23 may 06


Earl and all:
The melting point of diamond is about 3850 C. Well over 5000 F.
Thanks, Google .
Best,
Wayne Seidl

-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG] On Behalf Of Earl Brunner
Sent: Tuesday, May 23, 2006 1:34 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: NCECA 2007/ now: cones & antiquity

Hummmm, diamonds came to mind, do they "melt" when
heated high enough?

Ivor and Olive Lewis on wed 24 may 06


Dear Earl Brunner ,

You inquisitive little demon ! !

<enough?>>

Yes Earl, they do. Well over 3000 deg Celsius. But you have to take =
precautions to make it happen. Otherwise, they ignite and burn in air at =
about 800 deg Celsius, just like their allotropes, charcoal and =
graphite. All are elemental Carbon.

Enjoy the day.

Earl Brunner on wed 24 may 06


Now that would be something, liquid diamond, cast it in your own shape.

Ivor and Olive Lewis wrote: Dear Earl Brunner ,

You inquisitive little demon ! !

<>

Yes Earl, they do. Well over 3000 deg Celsius. But you have to take precautions to make it happen. Otherwise, they ignite and burn in air at about 800 deg Celsius, just like their allotropes, charcoal and graphite. All are elemental Carbon.

Enjoy the day.


Earl Brunner
e-mail: brunv53@yahoo.com