Penni Stoddart on wed 24 apr 02
I have just come into possession of some large cones after only using =
the small ones (they were within my budget) for the past four years. The =
last three firings I've had went rather faster then I had anticipated. I =
keep a record book with every firing in it. When each switch is turned =
on and off and the cone fired to. But like I said the last three which =
I used the large cones in seemed to have been done about an hour to a =
half hour earlier then anticipated based on my little book.
My kiln is an OLD Amaco and I only go by the witness cones, no kiln =
sitter, computer or other "high tech" method. I am wondering if the =
cones could be the difference or if the size of load makes a difference =
or what? Any kiln gods out there who can enlighten me to the "ways of =
the cone"?
TIA
~~~~
Penni Stoddart of Penelope's Pots
Now acting as PAST President,
Artisans London (Ontario, Canada)
I live in my own little world, but it's ok... they know me here
Earl Brunner on thu 25 apr 02
The question would be, "How do you glazes look?" According to the charts I
have, the larger cones do melt at a slightly lower temperature than the
smaller ones. It looks to me like about a cone difference. You might check
the archives, we just had a discussion on cones not to long ago.
Penni Stoddart wrote:
> I have just come into possession of some large cones after only using the
small ones (they were within my budget) for the past four years. The last
three firings I've had went rather faster then I had anticipated. --
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
chris clarke on thu 25 apr 02
Just a thought, but I believe the little cones are only for a kiln sitter
and would not bend at the intended temp standing up.
chris
temecula, california
chris@ccpots.com
http://www.ccpots.com
Bruce Girrell on thu 25 apr 02
Penni Stoddart wrote:
> I have just come into possession of some large cones after only
> using the small ones (they were within my budget) for the past
> four years. The last three firings I've had went rather faster
> then I had anticipated. I keep a record book with every firing in
> it. When each switch is turned on and off and the cone fired to.
> But like I said the last three which I used the large cones in
> seemed to have been done about an hour to a half hour earlier
> then anticipated based on my little book.
Small cones bend at a higher temperature than large cones. The small cones
are intended for use in a Dawson Kiln Sitter. While not intended for use as
witness cones, they can be used for that, but you must account for the
difference in temperature.
See www.ortonceramic.com for more information regarding the relationship
among types of cones, bending angle, and firing temperature.
Bruce "URL of the Day" Girrell
Cindi Anderson on thu 25 apr 02
Heavier loads will take longer to fire. But when you say small cone, do you
mean "Jr cones" which are for the kiln sitter, or "self supporting cones"
which are small witness cones. If you were using self supporting, they
should be the same as standard (large) cones. But if you were using Jr
cones that would explain the difference, as they have a different temp chart
because they are designed for use in the kiln sitter.
Cindi
Fremont, CA
----- Original Message -----
From: "Penni Stoddart"
To:
Sent: Wednesday, April 24, 2002 6:35 PM
Subject: the ways of the cone
I have just come into possession of some large cones after only using the
small ones (they were within my budget) for the past four years. The last
three firings I've had went rather faster then I had anticipated. I keep a
record book with every firing in it. When each switch is turned on and off
and the cone fired to. But like I said the last three which I used the
large cones in seemed to have been done about an hour to a half hour earlier
then anticipated based on my little book.
My kiln is an OLD Amaco and I only go by the witness cones, no kiln sitter,
computer or other "high tech" method. I am wondering if the cones could be
the difference or if the size of load makes a difference or what?
Valerie Hawkins on mon 29 apr 02
Earl said:
"The question would be, "How do you glazes look?" According to the charts I
have, the larger cones do melt at a slightly lower temperature than the
smaller ones. It looks to me like about a cone difference. You might check
the archives, we just had a discussion on cones not to long ago."
Now I'm confused!!!! I thought that the mini cones melted at a lower temp.
Almost a cone lower. If you want to reach cone 6 in your kiln, put a cone 7
mini in the sitter.
True or not true?
thanks,
Valerie
claybair on mon 29 apr 02
Hmmmm....
My last ^6 ox firing I had a ^8 bar in the sitter and ^6 test cones on each
shelf.
The test cones went down between 8 and 7 o'clock while the sitter ^8 bent
45degrees and turned off the kiln.
Gayle Bair
Bainbridge Island, WA
http://claybair.com
Earl said:
"The question would be, "How do you glazes look?" According to the charts I
have, the larger cones do melt at a slightly lower temperature than the
smaller ones. It looks to me like about a cone difference. You might check
the archives, we just had a discussion on cones not to long ago."
Now I'm confused!!!! I thought that the mini cones melted at a lower temp.
Almost a cone lower. If you want to reach cone 6 in your kiln, put a cone 7
mini in the sitter.
True or not true?
thanks,
Valerie
Frederich, Tim on thu 2 may 02
Hello to all,
Just a couple of comments on the recent discussion about cones. As a
"general" rule, the cone used in the KilnSitter should be one cone higher
than the witness cone used on the shelf. But this is not always true. Each
kiln is different and you need to observe your particular situation and
decide how to proceed.
The small cone was around before the invention of the KilnSitter and was not
formulated for this use. Small cones and large cones have different
equivalent temperatures at the same heating rate due to the size difference
in mass and height and the effect of gravity during the deformation of the
cone. The melting point of a small cone was determined just the same as a
large cone (mounting angle and height) and fired at a specific heating rate.
It was not with the assumption that it would be horizontal or weighted since
the KilnSitter was not invented.
The same mounting angle is used to mount both large and small cones and it
is the same angle in the self supporting cones. A large or small cone will
fall at different equivalent temperatures if the mounting angle is changed.
Best regards,
Tim Frederich
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