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bisque fire 25 minutes quicker - why?

updated mon 6 may 02

 

Martin Rice on sat 4 may 02


Had an interesting experience yesterday. I bisqued some pieces, the same =
number
and the same sizes as my first bisquing. But today, the cone slumped 25
minutes sooner than last time -- though I followed the same ramp up.

The only difference was that the first time, I had two shelves in and =
the
pots on the top shelf. This time, I had only the lower shelf in. Do you
think this might be the reason? In other words, the heat that was =
rising,
didn't have to rise over the bottom shelf before it got to the pots.

Not a big deal but if this reasoning makes sense than that's the way =
I'll continue doing it -- assuming
that I can fit everything on one shelf -- because at the price of
electricity here, pulling 220 volts at 45 amps costs a fortune, and 25
minutes sooner is like money in my pocket.

Best regards,
Martin
Lagunas de Bar=FA, Costa Rica
www.rice-family.org
Revised and updated 4/1/02

Snail Scott on sun 5 may 02


At 12:51 PM 5/4/02 -0500, you wrote:
>...today, the cone slumped 25
>minutes sooner than last time -- though I followed the same ramp up.
>The only difference was that the first time, I had two shelves in and the
>pots on the top shelf. This time, I had only the lower shelf in. Do you
>think this might be the reason? In other words, the heat that was rising,
>didn't have to rise over the bottom shelf before it got to the pots.


Doubt it; the convection that takes place inside
an electric kiln is not a lot, IMHO. More likely
that the reduced thermal mass accounts for it.
Your kiln has to heat up both the work and the
kiln furniture, and the shelves and posts together
sometimes have even more total mass than the
claywork does.

-Snail