F. Melville on sat 7 dec 96
Tony,
I once-fired exclusively for 4 years (using mostly Plainsman M325 and
other Plainsman clays) and did not experience crawling until I decided to
try bisquing some of my work. That, of course, was my fault - I was
obviously applying the glaze too thickly). The only problem I had with
once-firing was the occasional disintegration of teapots when too much
glaze accumulated inside them. I find that single-firing really suits some
of my pieces and that others are better bisqued. I never had any trouble
with glaze-fit on a single-fired object. I now single-fire birdfeeders
made from M332 whereas I bisque others made from Imco Navajo Wheel. I now
bisque all teapots. All a matter of personal preference. All done in a
small electric kiln.
Francoise
Indalo Pottery
Port Edward, B.C.
Canada
Jeff Lawrence on sun 8 dec 96
Confession of an apostate:
Yea, I did follow the siren song of once-firing. And tests did confirm my
hopes, building a spacious castle of efficiency in my thoughts. But lo the
gargoyles of that castle did quicken and humble me, scourging me back to
twice-fire land.
I've found that once-fires both crack on the edges and sag during the
firing. I theorize that this is because there are volatiles driven off in
the bisque firing that combine with glaze outgassings to soften the clay
more in combination than either would individually.
I talked to a jobber with a tunnel kiln producing for the lighting industry
and he recoiled from the idea of once-firing. He says that he tried it and
rejected it for the separate bisque and glaze firing. With twice-firing, he
says can order a truck to pick up his products even before he picks up a
spray gun. That's reliability.
Wish I were productive enough to have trucks on standby for my ware! Still
working on it in Espanola, where it's 8 degrees F in the morning and 60 in
the afternoon.
Jeff Lawrence
Sun Dagger Design
Rt 1 Box 394L
Espanola NM 87532
ph/fax 505-753-5913
AWM (Amused White Male)
F.Chapman Baudelot on wed 14 aug 02
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I am back to single firing after a couple of weeks of bisquing. It seems=20
that I just wasn't made to bisque and in my case it was most=20
uneconomical. I am managing to eke out a living making dozens of sgraffiti=
=20
souvenir ashtrays. Not what I really like doing , of course, and very=20
repetitive, but I do get to make two plates with each kiln load of 30=20
ashtrays. I used to fire the kiln to 1080 or thereabouts in 4 hours, but=20
today there was quite a wind blowing into the burner port and the=20
temperature shot up to over 300C=BA in less than an hour. This was saving=
me=20
a lot of gas, and as I heard no explosions, I just let it blow, reaching=20
full temperature in just 2 and a half hours. Two hours after that I=20
unloaded the kiln which also cools down very quickly. The 30 ashtrays,=20
stacked rim to rim and foot to foot, and two plates were just fine, if=20
anything better than with the usual 4 hour firing. This means that I can=20
easily do 2 firings every day and produce even more ashtrays. Smoking=20
European tourists are keeping me alive :)
I can probably do this because the red earthenware I use doesn't mind such=
=20
treatment. I dry it in the hot sun from just thrown to bone dry and can=20
fire it the same day I throw it. I glaze and decorate bone dry. As for=20
the glaze I am using (a mottled blue with some rutile ), on the one=20
occasion when I attempted to slow cool it, firing down, the result was some=
=20
rather uninteresting green patches on the outsides of the ashtrays and the=
=20
blue that remained on the insides was much 'flatter'.
It is not easy trying to be a production potter and using such a tiny kiln,=
=20
but at least here in Spain when the locals find out that I work as a=20
potter, no one mentions the word 'hobby' or asks me what I do as my real=20
job. Despite the repetition, I still take pride in my work and try to make=
=20
each piece as well as possible.
Francoise
http://indalopottery.tripod.com/fenix.html
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