Used wrong cones in kiln sitter - Help

I can't believe I did this. I fire in an electric kiln. I was rushing to get
in a ^6 GLAZE firing for an upcoming event and I use an 04 cone in my kiln
sitter instead of cone 6. In the morning I'm going to take all the cones out
and restart it but now I don't know if I should try to fire it to ^6 or try
firing a cone lower since it has already gotten some heatwork. I'm afraid
all the pieces will be overfired if I fire to ^6 now. Anyone have any
experience with this one?
Thanks,
Crystal

Go for ^6, some friends and I re-fire to the same cone, sometimes more
than once.

Steve
Bath
UK


In article , CNB
writes
I can't believe I did this. I fire in an electric kiln. I was rushing to get
in a ^6 GLAZE firing for an upcoming event and I use an 04 cone in my kiln
sitter instead of cone 6. In the morning I'm going to take all the cones out
and restart it but now I don't know if I should try to fire it to ^6 or try
firing a cone lower since it has already gotten some heatwork. I'm afraid
all the pieces will be overfired if I fire to ^6 now. Anyone have any
experience with this one?
Thanks,
Crystal



--
Steve Mills
Bath
UK

On Sun, 29 Oct 2006 21:57:35 -0600, "CNB"
wrote:

I can't believe I did this. I fire in an electric kiln. I was rushing to get
in a ^6 GLAZE firing for an upcoming event and I use an 04 cone in my kiln
sitter instead of cone 6. In the morning I'm going to take all the cones out
and restart it but now I don't know if I should try to fire it to ^6 or try
firing a cone lower since it has already gotten some heatwork. I'm afraid
all the pieces will be overfired if I fire to ^6 now. Anyone have any
experience with this one?
Thanks,
Crystal


No experience with this as such, but I'll be glad to throw out my
2 cent's worth on "heat work". I see this as a lot like conventional
melting, such as ice to water. Ice nominally melts at 32F (0C).
Now let's say you have a large block of ice you want to melt.
If you take it to 33F for an hour, you only get a little bit of it
melted. If you want to melt the whole thing and never
go above 33F, it might take many, many hours. Or you could
take it to (say) 60F and it would melt much faster.

But you can hold it at 31F forever and it won't melt.

So my point is that "heat work" has to be considered
relative to the melting point of the material. In the case
of ^6 glazes, the ^04 firing doesn't get very close to
the melting point, so it contributes negligible heat work.

Now clay and glazes are not exactly like pure water,
since they are mixtures of many substances with different
melting points, plus there are eutectic effects that can
lower the overall melting point below any of the individual
ones. So, yes, there probably is a small amount of
melting that happened in your ^04 firing, and if you held
the kiln at the peak ^04 temperature long enough you
would probably have a noticeable effect. But I'd guess
this is probably not going to be a problem in your rcase.

Best regards,



Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Home of DaqGen, the FREEWARE signal generator

Steve and Bob,

Thank you both so much. I feel a lot better now. In the 8 or so years I've
been firing
the kiln this has never happened so I had no idea how the next firing would
react.
Guess I've been pretty lucky. I'm re-firing right now. Whew!

Thanks,
Crystal

I had a similar experience once. The center ring of the kiln didn't
fire and I wasn't aware of it until it was too late. It happened on
the bisque load, prior the glaze load too. Didn't notice it on either
load.....(don't ask why - the head just does that sometimes). I
refired the glaze load to Cone ^6 and all but two pieces came out fine.
The two had bubbles. I believe the bubbles were caused by the bisque
being underfired and possible bubbles at that point. They just didn't
show up until the high fire.

I have also "refired" Cone^6, more than once. It works out fine. I
have a friend that will refire up to 6 times. I have only done it
twice. Can't afford the electric bill!!

Jan


CNB wrote:
I can't believe I did this. I fire in an electric kiln. I was rushing to get
in a ^6 GLAZE firing for an upcoming event and I use an 04 cone in my kiln
sitter instead of cone 6. In the morning I'm going to take all the cones out
and restart it but now I don't know if I should try to fire it to ^6 or try
firing a cone lower since it has already gotten some heatwork. I'm afraid
all the pieces will be overfired if I fire to ^6 now. Anyone have any
experience with this one?
Thanks,
Crystal