iandol on sat 6 jan 01
Dear Ian,
A Happy and Prosperous New Year to you.
Well, apart from asking you to explain ENTROPY for this dunce, I have to =
say that you strike the nail fairly and squarely on the head in regard =
to our lack of knowledge about firing times and heating rates and so on.
Though it may be of little consequence to the electric brigade, I have =
found from experience with gas and oil that during slow firings cones =
drop at lower temperatures. Though it takes longer I still get well =
matured glazes. By tuning the damper to make the hot gases stay inside =
the kiln longer, so they have time to deliver up their energy, there are =
noticeable savings in fuel consumption.
I can understand the reasoning of Steve Harrison as well. Most cooks =
will tell you that treacle has to be heated to make it flow. Increasing =
temperature lowers viscosity.
Best regards,
Ivor. Redhill, South Australia
Harry on sun 7 jan 01
HI Ivor,
I'll agree with you that you have to restrict the flow to contain the
heat and not let it just go up the stack. I have to convince people I work
with that you have to throttle back heat exchangers to find their most
efficient point.
Now would you mind telling me just what the heck "treacle" is? :))
Harry in Iowa, a balmy 44 degrees f. yesterday, snow drifts beginning to
dwindle.
----- Original Message -----
From: "iandol"
To:
Sent: Saturday, January 06, 2001 12:13 AM
Subject: Kilns, Firing Technology and Fuel Economy
Dear Ian,
A Happy and Prosperous New Year to you.
Well, apart from asking you to explain ENTROPY for this dunce, I have to say
that you strike the nail fairly and squarely on the head in regard to our
lack of knowledge about firing times and heating rates and so on.
Though it may be of little consequence to the electric brigade, I have found
from experience with gas and oil that during slow firings cones drop at
lower temperatures. Though it takes longer I still get well matured glazes.
By tuning the damper to make the hot gases stay inside the kiln longer, so
they have time to deliver up their energy, there are noticeable savings in
fuel consumption.
I can understand the reasoning of Steve Harrison as well. Most cooks will
tell you that treacle has to be heated to make it flow. Increasing
temperature lowers viscosity.
Best regards,
Ivor. Redhill, South Australia
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Wade Blocker on sun 7 jan 01
Harry,
Treakle is a sugar syrup,a little like dark corn syrup. Mia in ABQ
Steve Mills on mon 8 jan 01
My experience also backs up what you have to say about time, heat-work,
and final temperatures; our little wood kilns regularly fire to cone
ten/eleven, but never show an indicated temperature higher than 1200
degrees centigrade, and the glazes are always beautifully mature.
Steve
Bath
UK
In message , iandol writes
>Dear Ian,
>A Happy and Prosperous New Year to you.
>Well, apart from asking you to explain ENTROPY for this dunce, I have to =
>=3D
>say that you strike the nail fairly and squarely on the head in regard =3D
>to our lack of knowledge about firing times and heating rates and so on.
>Though it may be of little consequence to the electric brigade, I have =3D
>found from experience with gas and oil that during slow firings cones =3D
>drop at lower temperatures. Though it takes longer I still get well =3D
>matured glazes. By tuning the damper to make the hot gases stay inside =3D
>the kiln longer, so they have time to deliver up their energy, there are =
>=3D
>noticeable savings in fuel consumption.
>I can understand the reasoning of Steve Harrison as well. Most cooks =3D
>will tell you that treacle has to be heated to make it flow. Increasing =3D
>temperature lowers viscosity.
>Best regards,
>Ivor. Redhill, South Australia
--
Steve Mills
Bath
UK
Ian Currie on mon 8 jan 01
Greetings Ivor
Entropy is what I feel increasingly in my bones as I get older :) It's
actually a measure of the degree of disorder within a system... like the
universe, or the top of my desk, or a bucket of glaze materials you are
about to mix irreversibly together. The various glaze ingredients have a
certain degree of "order" while they are in their separate packages, but
when you mix them together a process takes place which to all practical
purposes is irreversible, and something is lost forever. Entropy increases,
free energy decreases, the universe becomes a bit more "disordered"... and
the laws of thermodynamics rule.
Anyway that's how it was explained to me when I was a student and had a lot
less of it (entropy) inside of me!
Cheers
Ian
http://ian.currie.to/
>Well, apart from asking you to explain ENTROPY for this dunce, I have to
say that you strike the nail fairly and squarely on the head in regard to
our lack of knowledge about firing times and heating rates and so on.
CraigD on mon 8 jan 01
>From Ivor =20
"I have found from experience with gas and oil that during slow firings =
cones=20
drop at lower temperatures."
Some hard data from the electric brigade to support your contention. =
>From the Edward Orton Jr. Foundation:
Large, self supporting cone...
Cone Number Degree F equiv. @ 108*F Degree F =
equivalent @ 270*F
per hour temperature rise. =
per hour, temperature rise
5 2151*F =
2185*F
6 2194*F =
2232*F
7 2219*F =
2264*F
8 2257*F =
2305*F
9 2300*F =
2336*F
10 2345*F =
2381*F
One can easily see that at there is almost a full cone difference based =
solely on this 162*F difference in the ramping schedules. I believe =
that I read someplace that this (Degree of F equivalent) pertains =
specifically to the last several hours of the firing, implying that you =
could ramp up quicker during the middle of the firing cycle.
My interpretation of this table is: If you were to fire without the aid =
of cones, just using an accurate digital thermometer, and if you fired =
the last several hours at a ramp up of 270* per hour, you would believe =
that you had reached cone 10 when the digital thermometer read 2345*F, =
.......but a quick glance at the table tells us otherwise...Cone 9 has =
just touched down....have to go another 36*F to reach Cone 10..
Anyway..seemed like interesting numbers.
Craig
Martin Howard on tue 9 jan 01
Treacle is the proper word. English english spelling. Comes in light, dark
and middling. Have the Americans even changed the spelling of that very
English basic food?
Lasts for years but then goes sugary. Makes good spooze.
Martin Howard of the spelling police at
Webb's Cottage Pottery
Woolpits Road, Great Saling
BRAINTREE, Essex CM7 5DZ
England
martin@webbscottage.co.uk
Cindy Strnad on tue 9 jan 01
Hi, Martin.
No, we haven't changed the spelling of treacle. But I'd never heard the word
until my little girl was given a "Roobarb" video. For those of you who don't
know, Roobarb is a delightful cartoon pup with a British accent.
And then, treacle gets mentioned in the Harry Potter books, which is why I
know how to spell it at all. I had always supposed it must be a sort of
molasses. Is it just made of cane sugar, then?
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
http://www.earthenvesselssd.com
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