Snail Scott on fri 10 nov 00
It seems to me that it's a little rough on the wiring to kick
it to 'high' right away. (I've fired mine with an amp-clamp on
the cable, just to watch what's happening.) The resistance in the
wiring is highest right after a turn-up, and diminishes as the
elements heat up. I often do only ten minutes each on 'low' and
'med' first though, with no ill effects. (If there's been damp weather,
I'll leave it on 'low' with the lid cracked for a little longer.)
(Yes, this is bisqued stuff we're talking about. Even I take longer for
green clay.)
-Snail
At 08:01 AM 11/10/00 -0500, you wrote:
>hello all.....is there any advantage to firing a glaze load in a electric
>kiln slow.....i have in the past....turned the kiln on high right from the
>start and have not had anything go wrong.....I'm I pushing my luck???? Is
>it bad for the elements? thanks.....dean
>
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dean warsing on fri 10 nov 00
hello all.....is there any advantage to firing a glaze load in a electric
kiln slow.....i have in the past....turned the kiln on high right from the
start and have not had anything go wrong.....I'm I pushing my luck???? Is
it bad for the elements? thanks.....dean
Clay Grigsby on sat 11 nov 00
dean, yes there are advantages to firing slow. you allow the glazes the
proper amount of time to melt and to interface with the clay body. there
needs to be an even heat rise through out the entire firing but if it is
working for you then leave it be i guess. good luck. clay
John Hesselberth on sat 11 nov 00
Clay Grigsby wrote:
>dean, yes there are advantages to firing slow. you allow the glazes the
>proper amount of time to melt and to interface with the clay body. there
>needs to be an even heat rise through out the entire firing but if it is
>working for you then leave it be i guess. good luck. clay
There can also be a significant advantage to cooling slowly, particularly
if you are working with true mattes or semimattes ( as opposed to those
mattes that just aren't completely melted). True mattes or semimattes
are the result of tiny crystals forming during cooling. That takes time.
I find that cooling at about 150 deg F per hour down to 1500 deg F does
the trick. To me that is the biggest single advantage of a computer
controlled kiln--the ability to fire down at the rate you specify.
Regards, John
John Hesselberth
Frog Pond Pottery
P.O. Box 88
Pocopson, PA 19366 USA
EMail: john@frogpondpottery.com web site: http://www.frogpondpottery.com
"It is, perhaps, still necessary to say that the very best glazes cannot
conceal badly shaped pots..." David Green, Pottery Glazes
Rod, Marian, and Holly Morris on sun 12 nov 00
I can't speak for what fast firing does to the elements, but I have had a
few bad experiences with my small electric kiln when I tried to fire a
fairly full load too fast (faster than 350 p/h heat rise). Uneven heating
was the issue. Some areas came out underfired.
Certain glazes do better in a slower fire (crystalline commercial glazes,
for example), and some, like the reds, like it fast. I guess experimentation
is the key.
Marian in Michigan
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