Ivor and Olive Lewis on sat 8 mar 08
Dear Miles Smith,=20
Regarding the thermal conductivity of glass.
Today I needed a dropper pipette. so I took a piece of 6 mm dia glass =
tubing and cut a length, about 200 mm long. Out of habit I always flame =
polish the raw ends of glass tubing. This can be done by just raising =
the tube end to dull red heat, about 600-650 deg C. First end is always =
easy because you can keep your hands well away from the flame. Held my =
tube at the centre for the second end. before the glass got hot enough =
to polish heat from the first end was conducted to my fingers at the =
centre of the tube and was severe enough to cause mild discomfort.
Thermal conductivity of :
Pyrex Glass 1.1 Watts.per metre per degree Kelvin
Quartz (c axis) 11.6 w.m.k
Fused Silica 1.33 w.m.k
Alumina 40 w.m.k
Porcelain 1.5 w.m.k
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Miles Smith on sun 9 mar 08
Ivor, thank you for the detail.
There is an interesting synergy happening around me now that I can entertain
the idea that what I believe about the my chemistry has limited what I can
believe about myself. Now through this new interest in measurable
observation in my studio, I see a better possibility in my person.
I saw the film "Ali" last night, and was excited by Ali's John Lennon's
quote to him, "the more real you become the crazier it becomes."
"....send out the clowns".
Miles Smith
----- Original Message -----
From: "Ivor and Olive Lewis"
To:
Sent: Saturday, March 08, 2008 12:22 AM
Subject: Question regardsing Mat Liner Glazes
Dear Miles Smith,
Regarding the thermal conductivity of glass.
Today I needed a dropper pipette. so I took a piece of 6 mm dia glass tubing
and cut a length, about 200 mm long. Out of habit I always flame polish the
raw ends of glass tubing. This can be done by just raising the tube end to
dull red heat, about 600-650 deg C. First end is always easy because you can
keep your hands well away from the flame. Held my tube at the centre for
the second end. before the glass got hot enough to polish heat from the
first end was conducted to my fingers at the centre of the tube and was
severe enough to cause mild discomfort.
Thermal conductivity of :
Pyrex Glass 1.1 Watts.per metre per degree Kelvin
Quartz (c axis) 11.6 w.m.k
Fused Silica 1.33 w.m.k
Alumina 40 w.m.k
Porcelain 1.5 w.m.k
Best regards,
Ivor Lewis.
Redhill,
South Australia.
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