Mike O'Brien on tue 12 dec 00
Lorri, I have a huge amount of experience with electric hobby kilns. The big
question I have is what you are firing. Thrown , hand build or slip cast.
My experience is strictly slipcast. I cant imagine there would be any
difference with a cold outside temp unless the water in your greenware is
frozen.
Mike O'Brien
Lorri on tue 12 dec 00
I have not had experience with kiln firings in low temperatures. Am hoping
someone can explain to me how to alter my firing or if alteration is even
necessary. What I have done until now is this: on bisque firings - with
lid propped all the way up and peeps unplugged, fire for 8 hours on low;
lower lid a notch (still slightly open) with peeps still unplugged, fire
another 4 hours on low; with lid closed and peeps now plugged, fire on
medium 4 hours; raise the temp to high until bisque has reached cone and
kiln shuts off. I have a small Paragon electric kiln with only one temp
control. Here's my question. The kiln is in the garage which is not
insulated. Temperatures have been between 0 to 10 degrees farenheit.
Should the firing change at all because of these temps? Common sense tells
me these temperatures would be different than when it is 85 degrees outside.
BTW, I have no technical place to look for this information. I check
everything out at the library I can get my hands on but this is too
technical for basic books and ...well, anyhow am hoping someone doesn't mind
responding.
Thanks,
Lorri
Lenexa, KS
CINDI ANDERSON on tue 12 dec 00
The only change I would see is maybe to fire longer at low, since you will be
starting colder and want to make sure you drive all the water out. Other than
that, it should take longer to get to temperature, but the cone will still tell you
when to turn off.
Cindi
Lorri wrote:
> I have not had experience with kiln firings in low temperatures. Am hoping
> someone can explain to me how to alter my firing or if alteration is even
> necessary. What I have done until now is this: on bisque firings - with
> lid propped all the way up and peeps unplugged, fire for 8 hours on low;
> lower lid a notch (still slightly open) with peeps still unplugged, fire
> another 4 hours on low; with lid closed and peeps now plugged, fire on
> medium 4 hours; raise the temp to high until bisque has reached cone and
> kiln shuts off. I have a small Paragon electric kiln with only one temp
> control. Here's my question. The kiln is in the garage which is not
> insulated. Temperatures have been between 0 to 10 degrees farenheit.
> Should the firing change at all because of these temps? Common sense tells
> me these temperatures would be different than when it is 85 degrees outside.
> BTW, I have no technical place to look for this information. I check
> everything out at the library I can get my hands on but this is too
> technical for basic books and ...well, anyhow am hoping someone doesn't mind
> responding.
> Thanks,
> Lorri
> Lenexa, KS
>
> ______________________________________________________________________________
> 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.
Daniel Foscarini on tue 12 dec 00
I have an electric test kiln (small small small) with only one temp setting.
(no peep holes ), I bisque fire at cone 6 ( I do everything at cone 6, got
them cheap). I close the lid completely, and fire at will.
The differance..... I only fire BONE DRY clay, that I have wedged the hell
out of. End result, no cracks. Which is why I assume you go threw all of
this process, not to end up with cracks.
Some points which might make a differance between you and me. 1) the clay I
use might be really good for this I don't know, I gather it from the local
creek. 2) although mine is in an uninsultated add-on like your garage, I
only use the test kiln which is small, size might matter. 3) I swear by the
cone switch, without it I'm sure I would have burned down my mobile home
long ago.
Dan
>From: Lorri
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Help on kiln firing
>Date: Tue, 12 Dec 2000 15:19:58 -0600
>
>I have not had experience with kiln firings in low temperatures. Am hoping
>someone can explain to me how to alter my firing or if alteration is even
>necessary. What I have done until now is this: on bisque firings - with
>lid propped all the way up and peeps unplugged, fire for 8 hours on low;
>lower lid a notch (still slightly open) with peeps still unplugged, fire
>another 4 hours on low; with lid closed and peeps now plugged, fire on
>medium 4 hours; raise the temp to high until bisque has reached cone and
>kiln shuts off. I have a small Paragon electric kiln with only one temp
>control. Here's my question. The kiln is in the garage which is not
>insulated. Temperatures have been between 0 to 10 degrees farenheit.
>Should the firing change at all because of these temps? Common sense tells
>me these temperatures would be different than when it is 85 degrees
>outside.
>BTW, I have no technical place to look for this information. I check
>everything out at the library I can get my hands on but this is too
>technical for basic books and ...well, anyhow am hoping someone doesn't
>mind
>responding.
>Thanks,
>Lorri
>Lenexa, KS
>
>______________________________________________________________________________
>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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Dave Finkelnburg on wed 13 dec 00
Lorri,
The best thing I think I ever did to understand my small electric kiln
with no controller was buy a digital pyrometer for it. I started out
firing somewhat as you do, but with the pyrometer I could see that I was
firing at about 50 degrees/hour, which was much slower than needed. Now I
know where and when I can speed things up. I fire faster now with lighter
loads--the kiln heats faster, etc.
I think you can safely fire greenware at about 150 degrees F/hour
temperature rise, bisque ware at twice that rate (300 degrees F/hour), for
reasonable thickness pieces. If you have anything over 3/4-inch wall
thickness, then slower is probably appropriate.
I have also discovered these "rules" can be broken. I have learned
through experience I can fire some of my ware very nicely to cone 10 in 4
hours from a cold kiln, did it last week in 15-degree weather. You have to
be brave once in a while and try things, preferably with pieces you can
afford to lose :-) and learn what the limits are for your work, your clay
and glazes, in your kiln.
Good firing!
Dave Finkelnburg
Idaho Fire Pottery
-----Original Message-----
From: Lorri
To: CLAYART@LSV.CERAMICS.ORG
Date: Tuesday, December 12, 2000 2:26 PM
Subject: Help on kiln firing
>I have not had experience with kiln firings in low temperatures. Am hoping
>someone can explain to me how to alter my firing or if alteration is even
>necessary. What I have done until now is this: on bisque firings - with
>lid propped all the way up and peeps unplugged, fire for 8 hours on low;
>lower lid a notch (still slightly open) with peeps still unplugged, fire
>another 4 hours on low; with lid closed and peeps now plugged, fire on
>medium 4 hours; raise the temp to high until bisque has reached cone and
>kiln shuts off. I have a small Paragon electric kiln with only one temp
>control. Here's my question. The kiln is in the garage which is not
>insulated. Temperatures have been between 0 to 10 degrees farenheit.
>Should the firing change at all because of these temps? Common sense tells
>me these temperatures would be different than when it is 85 degrees
outside.
>BTW, I have no technical place to look for this information. I check
>everything out at the library I can get my hands on but this is too
>technical for basic books and ...well, anyhow am hoping someone doesn't
mind
>responding.
>Thanks,
>Lorri
>Lenexa, KS
>
>___________________________________________________________________________
___
>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.
>
WHew536674@CS.COM on wed 13 dec 00
Lorri,
If I counted on my fingers correctly I understood you to have the kiln on low
and med. for 16 hours before you switched to high. If you are firing pots,
you can speed it up. When I do a bisque I fire on low for an hour (lid
cracked a bit, plugs out) come back in an hour, close lid, switch to med.,
come back in an hour and put on high and put plugs in. Kiln reaches cone 05
a couple hours later. Never had any problems with pots exploding, always dry
when I put them in. Total firing time about 5 to 6 hours.
Joyce A
Fara Shimbo on wed 13 dec 00
Hi, folks,
I'm new to the list, but I wanted to add my two cents about
electic kilns and outside temperatures.
Where I live (northern Colorado, in a town so rural the
population doubles every calving season and people are
still on party lines), the outside temperature makes a
*huge* difference in firing, mainly because of the voltage
on the line.
Out where I am, I can fire three shelves of marcrocrystalline
ware (my specialisation) to ^10 in my Skutt 818 in four to
four and a half hours when the weather is too cold for everyone
to have their air conditioners on, and too warm for them
to have their space heaters on. Also, out here I have to
time my firings so that everything is done before about 4 PM
because once folks start cooking, again there is no power.
I just started a firing at 0530, hoping it will be done by
noon. It's well below zero out here and I know the whole
neighborhood (all ten of us) will be using electic heaters
and so on, so I wanted the peak of my fire to be during the
time of day most folks are out of their houses on chores
or errands.
I didn't fire at all this past summer, save once. I had just
replaced the elements in the kiln and I still had to keep
spraying the kiln with water from a spritz-bottle to
get it to heave up to ^8 in 9 hours. It was in the 40s C
outside and everyone in the county had their air conditioners
on. These were the same elements (with ITC 213 on them) that
were going to ^10 in 4 hours last week.
Also, about not being able to see the witness cones,
I always put them at the back of the kiln so that they're
visible against the elements. Never have a problem seeing
them that way, although with the glazes I use my atmosphere
is usually very clear.
Fa
------
Fara Shimbo
Certified Public Nuisance
http://home.earthlink.net/~fashimbo
Lorri on wed 13 dec 00
Joyce,
Yep, your fingers are working properly! Wow, what a difference in how
long I was told to fire on low and medium versus what you stated. I'll try
what you suggest and see if I get any difference. The only concern I guess
being that all of the moisture is able to get out slowly. BTW, this is for
thrown pots, not sculpture or hand-built, bisquing to cone 06 (since someone
asked).
Thanks for the reply,
Lorri
Lenexa, KS
.....with the largest amount of snowfall today in at least 2 years and ready
for summer (but my dogs are loving it)!
> If I counted on my fingers correctly I understood you to have the kiln on
low
> and med. for 16 hours before you switched to high. If you are firing
pots,
> you can speed it up. When I do a bisque I fire on low for an hour (lid
> cracked a bit, plugs out) come back in an hour, close lid, switch to med.,
> come back in an hour and put on high and put plugs in. Kiln reaches cone
05
> a couple hours later. Never had any problems with pots exploding, always
dry
> when I put them in. Total firing time about 5 to 6 hours.
> Joyce A
>
>
____________________________________________________________________________
__
> 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.
>
michael wendt on thu 14 dec 00
Lorri,
Dave is right about digital pyrometers and for a little extra, you can get
ones that record the data internally. My model 91100-50 from Cole-Parmer
www.coleparmer.com records 1000 data points at any interval I choose and can
down load to a computer if you wish.
Regards,
Michael Wendt
----- Original Message -----
From: Dave Finkelnburg
To:
Sent: Wednesday, December 13, 2000 9:02 PM
Subject: Re: Help on kiln firing
> Lorri,
> The best thing I think I ever did to understand my small electric kiln
> with no controller was buy a digital pyrometer for it. I started out
> firing somewhat as you do, but with the pyrometer I could see that I was
> firing at about 50 degrees/hour, which was much slower than needed. Now I
> know where and when I can speed things up. I fire faster now with lighter
> loads--the kiln heats faster, etc.
> I think you can safely fire greenware at about 150 degrees F/hour
> temperature rise, bisque ware at twice that rate (300 degrees F/hour), for
> reasonable thickness pieces. If you have anything over 3/4-inch wall
> thickness, then slower is probably appropriate.
> I have also discovered these "rules" can be broken. I have learned
> through experience I can fire some of my ware very nicely to cone 10 in 4
> hours from a cold kiln, did it last week in 15-degree weather. You have
to
> be brave once in a while and try things, preferably with pieces you can
> afford to lose :-) and learn what the limits are for your work, your
clay
> and glazes, in your kiln.
> Good firing!
> Dave Finkelnburg
> Idaho Fire Pottery
>
>
> -----Original Message-----
> From: Lorri
> To: CLAYART@LSV.CERAMICS.ORG
> Date: Tuesday, December 12, 2000 2:26 PM
> Subject: Help on kiln firing
>
>
> >I have not had experience with kiln firings in low temperatures. Am
hoping
> >someone can explain to me how to alter my firing or if alteration is even
> >necessary. What I have done until now is this: on bisque firings - with
> >lid propped all the way up and peeps unplugged, fire for 8 hours on low;
> >lower lid a notch (still slightly open) with peeps still unplugged, fire
> >another 4 hours on low; with lid closed and peeps now plugged, fire on
> >medium 4 hours; raise the temp to high until bisque has reached cone and
> >kiln shuts off. I have a small Paragon electric kiln with only one temp
> >control. Here's my question. The kiln is in the garage which is not
> >insulated. Temperatures have been between 0 to 10 degrees farenheit.
> >Should the firing change at all because of these temps? Common sense
tells
> >me these temperatures would be different than when it is 85 degrees
> outside.
> >BTW, I have no technical place to look for this information. I check
> >everything out at the library I can get my hands on but this is too
> >technical for basic books and ...well, anyhow am hoping someone doesn't
> mind
> >responding.
> >Thanks,
> >Lorri
> >Lenexa, KS
> >
>
>___________________________________________________________________________
> ___
> >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.
> >
>
>
____________________________________________________________________________
__
> 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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