Rick Monteverde on sun 4 mar 01
At 12:50 PM -0800 3/4/01, Joyce Lee wrote:
>This pot has been sitting under
>"the" tree as a supply of water for our small creatures for about four
>years.... has worked well in its assigned task. Until TODAY there was
>an abrupt noise and the cracks/breaks occurred.
Microcracks propagated through 4 years of heating/cooling -
feezing/thawing cycles finally grew to the yield point, with residual
stress from the overfiring providing the necessary force to break it
all apart. Just a guess.
- Rick Monteverde
Honolulu, HI
Joyce Lee on sun 4 mar 01
At the exact moment I stepped off the patio this morning on my trundle
out to the newspaper box, a small wide-rimmed bowl cracked... it was
maybe 6" by 3" ... split into three triangular pieces. This bowl has a
history. It was in the first electric kilnload I'd ever completed...
mucho errors in that load... good reason as I later discovered. I ... in
my Black Hole of ignorance ... decided (yes, I did apply a fair amount
of brainpower after carefully reading the accompanying directions for
firing) that since my electric Cress went to ^10, it was ALWAYS supposed
to be fired to ^10. So this first load of greenware ... no bisquing....
had never heard of "once fire" ... was taken to ^10. Since my clay was
^5, most of the vessels .... all loosely resembling bowls, as I recall
.... sort of half melted or leaned until their rims touched the shelves.
One piece did survive in its intended form ... looked and felt much like
concrete... a very porous concrete. This pot has been sitting under
"the" tree as a supply of water for our small creatures for about four
years.... has worked well in its assigned task. Until TODAY there was
an abrupt noise and the cracks/breaks occurred. Anybody able&willing to
hazard a guess as to what happened?? NOT that this experience is going
to be repeated, mind you ...... just curious.
Joyce
In the Mojave
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