Jonathan Pennington on mon 17 dec 01
Here's a story of stupidity, and a question about slowing the cooling
rate/raising efficiency of an electric kiln.
I've got a Skutt 3 ring with 2.5in sides. I'm getting close to fed up
with the way the temperature drops like a damn stone, screwing up
glazes and more than once dunting pots in both bisque and glaze
fires. I'm trying to think of things to slow down the cooling and
reduce the incredible amount of heat that escapes this kiln. Honestly,
if I new then what I know now, I would not have bought an electric
kiln like this, instead spending my $1200 on bricks, burners and
books.
Anyway, one night not long ago- as I was remembering the bright orange
lights that shine from between each of the rings of my kiln (talk
about inefficient), I got the idea that the pots in my next firing,
with my newly formulated glazes, were too precious to ruin by
fast cooling. I decided to take the kaowool blanket (see it coming?)
that I have for a future raku kiln, and cut sections to place in
between the sections of the kiln. Worked great, no more bright orange
light and heat escaping between them. However, after the kiln reached
temp, I could still see it dropping *way* too fast. I got the idea
that if I took the longer piece of kaowool and (you guessed it)
wrapped it very loosely around the kiln (Avoiding the corner where the
automagic timer sits), then take the short piece and place it on top
of the kiln, that would dramatically slow cooling.
Well, it did that. It held so much heat that the kiln lid was glowing
orange when I removed the top wool piece to check it. It also held so
much heat that it literally melted the piece that locks the arm that
holds the kiln lid open. It melted it all over the side of the
kiln. It gave the kiln a nice bluish sheen as well.
Of course, I haven't made that mistake again. However, I did place a
single layer of IFB on top of the kiln once, and even just this slowed
cooling a great deal. I was wondering if anyone knew of any long term
problems with mortaring together a set of kiln bricks about the same
size as my kiln lid to use when I fire my kiln. The weight of a single
layer of kiln bricks is not a lot, and it really helps to insulate the
kiln a surprising amount, even without any more insulation on the
sides.
-J
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Jonathan Pennington | jwpennin@bellsouth.net
"It's hard to take life too seriously
when you realize yours is a joke." -me
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