Janet H Walker on wed 10 feb 99
Someone asked whether having an Envirovent would help even out the firings.
With the vent and no change to packing style, you'll probably find that
the bottom is firing higher than the top. Sometimes quite a lot higher.
This can be fixed of course even if you are using a controller to run the
firings. My last firing, with a vent, was COMPLETELY even top and bottom.
First time (after lots of tries)! Now I am convinced by experience that
it can be done; before I was convinced in principle!
I always fire with a "cap shelf". This keeps the pieces on the top shelf
from having little cool underfired spots. The cap shelf can be as little
as 1/2 inch under the lid. The air will find its way through.
then you just adjust the shelves and the load. The heat will even out if
you use two half shelves with a crack between them rather than all full
shelves. I often load the whole middle section with tall pieces next to
kiln sitter and pyrometer and (an odd number of) half shelves on the other
half for plates and low things. If you don't have very many tall things,
stand some tall kiln posts in there to masquerade as pots in the heat sink
sense.
Keep notes on how you pack the kiln and on what happened. There is no need
to put up with horribly uneven firings unless you want them for other
aesthetic purposes.
Regards,
Jan Walker
Cambridge MA USA
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