cookie davis on tue 9 oct 01
Dear All,
Greetings! I am a relative newbie with recent bad luck with my kiln firings
(well, and kilns in general-long story, won't bore you...). I have been
going by my basic knowledge of bisque/glaze firing and have found my good
outcomes few and far between. My bisque method seems to not be the problem.
The problem appears to by the glaze method of firing. In college we had
reduction cone 10 to which I have no problem with. The problem, as usual in
cases like mine (post grad. work, on my own finally to work), is that I no
longer have redux.gas firing and am learning (keyword: learning) how to do
cone 6 oxidation. Please, who ever can help me understand the subtle
intricasies of this and any firing, help me out by explaining your methods
on glaze firing. I have been reading and reading a lot but find that
other's experiences and words have more impact on my learning than by
reading books alone. For example, I have been reading all over the place
about "soak time"...I have never been taught what that is...how does one
physically do this during the firing...and why? Please help. Any advice is
appreciated.
Thank you all for your help and time.
Sincerely,
Cookie
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dayton j grant on tue 9 oct 01
Hey Cookie, Im building a kiln right now and really evry kiln is fired
differently so you would have to elaborate on what kind of kiln you have
,inside dementions,
the size of the burner holes
the size of the damper
upraft ,downdraft ,crossdraft
stuff like that ,you know 'specs'
Dayton shazam76@juno.com
On Tue, 9 Oct 2001 10:40:32 -0400 cookie davis
writes:
> Dear All,
>
> Greetings! I am a relative newbie with recent bad luck with my kiln
> firings
> (well, and kilns in general-long story, won't bore you...). I have
> been
> going by my basic knowledge of bisque/glaze firing and have found my
> good
> outcomes few and far between. My bisque method seems to not be the
> problem.
> The problem appears to by the glaze method of firing. In college
> we had
> reduction cone 10 to which I have no problem with. The problem, as
> usual in
> cases like mine (post grad. work, on my own finally to work), is
> that I no
> longer have redux.gas firing and am learning (keyword: learning)
> how to do
> cone 6 oxidation. Please, who ever can help me understand the
> subtle
> intricasies of this and any firing, help me out by explaining your
> methods
> on glaze firing. I have been reading and reading a lot but find
> that
> other's experiences and words have more impact on my learning than
> by
> reading books alone. For example, I have been reading all over the
> place
> about "soak time"...I have never been taught what that is...how does
> one
> physically do this during the firing...and why? Please help. Any
> advice is
> appreciated.
>
> Thank you all for your help and time.
>
> Sincerely,
>
> Cookie
>
> _________________________________________________________________
> Get your FREE download of MSN Explorer at
> http://explorer.msn.com/intl.asp
>
>
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Cindy Strnad on tue 9 oct 01
Dear Cookie,
Please tell us the size of your kiln, brand, type
of controller, what sort of problems you've been
having.
Thanks,
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
cindy@earthen-vessels-pottery.com
http://www.earthen-vessels-pottery.com
iandol on wed 10 oct 01
Dear Cookie Davis=20
Dwell time is an additional time added at your peak temperature after =
your set Orton cone has dropped. It allows the more refractory materials =
in your glaze to dissolve into the fluxing agents, which are the frits, =
calcium borates or feldspars, after they have melted.
One important issue is the way many people regard refractory materials =
such as Whiting (calcium carbonate) Magnesia (Talc or Dolomite)and =
Strontium carbonate. They are also called fluxes. This is confusing =
since they do not cause melting. They change other properties like =
fluidity, glass stability, colour response and surface finish. Since =
these compounds have very high melting points it is important to ensure =
they fully dissolve to create a homogeneous viscous fluid which will =
cool and become glassy. To ensure this once the cones have dropped the =
kiln temperature is held constant for a period of time. I allow two =
hours for my cone 8 firings. You may have read recent posts about =
mistakes where the dwell was extended for several hours without any =
catastrophic consequences.
By the way, are you suggesting that the institution which graduated you =
did not teach you kiln management and the theories and practices of =
firing?
Hope that helps,
Best regards,
Ivor Lewis. Redhill, South Australia
jay s. gertz on wed 10 oct 01
Cookie,
I too have had difficulty getting a decent result from my electric kiln
after using the cone 10 gas kiln in school. I have recently given up
trying single glaze coats on pots and am going to try layering glazes
and using low fire glazes/slips/engobes and see if this increases my
personal satisfaction with my work.
Richard Zakin has a book Electric Kiln Ceramics and there are others out
specifically on oxidation firings. The soaking did not seem to improve
nor deteriorate my results. I expanded my reading and have come to the
conclusion that layering and low fired glazes (cone 06-04) may be the
ticket.
jay
jay s. gertz
(jgertz@bulldog.unca.edu)
(828) 251-6627
scott lykens on wed 10 oct 01
heres a good rule of thumb with electric kilns,,, fire them like gas kilns.
For instance, how many times have you loaded a gas kiln and had it on as
high as it can possibly go inside 3 hrs, then feeling comfortable enough to
go home?? probably not often. Most folks dont even turn the gas up as high
as it can possibly go.
typically you might spend over night on pilot growing slowly to 6-700 over
8-9 hours, then slowly bumping it up to a inch or 2 of pressure. This out
of an available 6-10. compare that to an electric maybe you never turn an
infinate switch past 3. even though it goes to 6 or 10. This is just an
example, so dont get too literal but you can see how we customarily we fire
to fast and cool to fast.
Same rules for electric. And just because the computer says slow on the
button doesnt mean as slow as you fire without a computer, it means slow
compared to medium, or fast. alll these may still be too fast for you.
Instead of soaking at the end, try doubleing the amount of time you spend
getting from 1000 to1800 degress. if that doesnt work, double it again. or
some time ask your computer to do 100 degress an hour to 200 holding for a
few then continue in htis way till the end. granted its a long firing, but
whne you see great results you can back of till you see bad ones return and
know how to fix problems from there.
I would say 99% of all the glaze problems folks call me with are solved by
firing slow. The others tend to be the wrong glaze or clay for the desired
job. Something like putting a stain in a zinc glaze that says do not use
with zinc.
>From: "jay s. gertz
"
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: kiln firing theories...advice needed and appreciated
>Date: Wed, 10 Oct 2001 11:32:47 -0400
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>Cookie,
>
>I too have had difficulty getting a decent result from my electric kiln
>after using the cone 10 gas kiln in school. I have recently given up
>trying single glaze coats on pots and am going to try layering glazes
>and using low fire glazes/slips/engobes and see if this increases my
>personal satisfaction with my work.
>
>Richard Zakin has a book Electric Kiln Ceramics and there are others out
>specifically on oxidation firings. The soaking did not seem to improve
>nor deteriorate my results. I expanded my reading and have come to the
>conclusion that layering and low fired glazes (cone 06-04) may be the
>ticket.
>
>jay
>
>jay s. gertz
>(jgertz@bulldog.unca.edu)
>(828) 251-6627
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at
>melpots@pclink.com.
_________________________________________________________________
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