Paul & Kathy Greaves on sat 9 mar 02
One possibility for what's wrong is trapped gasses in your kiln. If you
don't have a kiln vent that's actively pulling air through, you'll need to
keep the top peephole open until the firing is complete. This allows the
volatiles a place to escape.
Kathy
> When I begin firing, I leave the vents open and the
> lid propped. My kiln has 6 switches that have to be
> flipped from the bottom up. Without going through my
> complete firing schedule, I'll just say that I
> gradually turn up the kiln one switch at a time. I
> close the lid after I flip the second switch and close
> the vents all but the top one. I close the top vent
> after the next switch.
pottershands@JUNO.COM on sat 9 mar 02
Please, I need some suggestions right away.
I am having an awful time with creators. My pots are
completely covered, inside and out with them.
I first started noticing them on the underside of
several pots in the middle of the kiln and on the top
and bottom of the pots on the bottom of the kiln.
I've been firing to cone 5. At one time, most of my
pots turned out pretty good with only a few blisters
or creators here and there. I've been trying to figure
out why. I tried firing slower. That didn't help. In
fact, more pots seemed to be ruined. Last night, I
fired slow and to cone 6. OH MY GOODNESS, almost
EVERYTHING was totally covered with creators - inside
and out - top and bottom. I had re-fired some things
that only had a few bubbles and now they are
completely full of bubbles.
The glazes are not too thick because even the thinest
of glaze has teeny tiny creators. I've never really
had a problem before, but now it's out of control.
When I begin firing, I leave the vents open and the
lid propped. My kiln has 6 switches that have to be
flipped from the bottom up. Without going through my
complete firing schedule, I'll just say that I
gradually turn up the kiln one switch at a time. I
close the lid after I flip the second switch and close
the vents all but the top one. I close the top vent
after the next switch.
Any help would be greatly appreciated. Thank you in
advance.
GEM
Julie Milazzo on sat 9 mar 02
What cone are you bisquing to? If it's 06, try 05, if
you fire to 05, try 04, and if you already fire to 04,
I don't think I have anymore advice. Could it be the
clay body? Julie
--- pottershands@JUNO.COM wrote:
> Please, I need some suggestions right away.
>
> I am having an awful time with creators. My pots are
> completely covered, inside and out with them.
>
> I first started noticing them on the underside of
> several pots in the middle of the kiln and on the
> top
> and bottom of the pots on the bottom of the kiln.
>
> I've been firing to cone 5. At one time, most of my
> pots turned out pretty good with only a few blisters
> or creators here and there. I've been trying to
> figure
> out why. I tried firing slower. That didn't help. In
> fact, more pots seemed to be ruined. Last night, I
> fired slow and to cone 6. OH MY GOODNESS, almost
> EVERYTHING was totally covered with creators -
> inside
> and out - top and bottom. I had re-fired some things
> that only had a few bubbles and now they are
> completely full of bubbles.
>
> The glazes are not too thick because even the
> thinest
> of glaze has teeny tiny creators. I've never really
> had a problem before, but now it's out of control.
>
> When I begin firing, I leave the vents open and the
> lid propped. My kiln has 6 switches that have to be
> flipped from the bottom up. Without going through my
> complete firing schedule, I'll just say that I
> gradually turn up the kiln one switch at a time. I
> close the lid after I flip the second switch and
> close
> the vents all but the top one. I close the top vent
> after the next switch.
>
> Any help would be greatly appreciated. Thank you in
> advance.
>
> GEM
>
>
______________________________________________________________________________
> 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/
>
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> reached at melpots@pclink.com.
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Kathy Maves on sat 9 mar 02
HI Gem,
Could you tell us a little more about the clay and
glazes that you use? Also, do you use cones to check
what temps. the kiln is actually reaching?
Kathy
Barronett, WI
kathymaves@yahoo.com
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annelorre dostal on sat 9 mar 02
i fire to cone 5/6 in an electric kiln, it sounds to me like it could be one
of several things, and the best way to test is eliminate the easiest.
first, make sure your bisque is free of dust, wash it and let it set for a
day before glazing.
as others have suggested, use cones to test the temp. in your kiln, blisters
and craters can be caused by overfiring.
are you using commercial or homemade glazes?
make sure your glazes do not become contaminated, always replace lids so
that studio dust does not settle in there.
hope this was helpful
annelorre
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Mondloch on sat 9 mar 02
Hi,
Based on what you wrote and recent problems of my own, I'd guess that you
have out-gassing from either the claybody or glazes from overfiring.
Was the problem on several glazes or only one? Only one glaze would indicate
to me a glaze problem, whereas more would indicate a clay problem.
I would try this:
-Only fire to a soft ^5 and after you reach temp, let it drop some before
you do any soak.
- You didn't mention a kiln vent? I've become a believer in keeping a
sufficient airflow through a kiln and would keep the vent turned on from the
beginning through the early part of the cool-down to carry any volatiles
away. Related to this is not packing too tightly. You want to keep enough
space between pieces for air movement.
-I'd also want to eliminate the bisque firing as a source of the problem.
Bisque slow,perhaps with a soak at the end, making sure you keep the vent on
for the whole time.
Good luck, I know it can be soooo frustrating.
Sylvia Mondloch
---
Mark & Sylvia Mondloch
Silver Creek Pottery & Forge
W6725 Hwy 144
Random Lake ,Wi 53075
HotArt@silvercreekpottery.com
http://www.silvercreekpottery.com
----- Original Message -----
From:
To:
Sent: Saturday, March 09, 2002 12:59 AM
Subject: cone 5/6 firing - HELP!!!
> Please, I need some suggestions right away.
>
> I am having an awful time with creators. My pots are
> completely covered, inside and out with them.
>
> I first started noticing them on the underside of
> several pots in the middle of the kiln and on the top
> and bottom of the pots on the bottom of the kiln.
>
> I've been firing to cone 5. At one time, most of my
> pots turned out pretty good with only a few blisters
> or creators here and there. I've been trying to figure
> out why. I tried firing slower. That didn't help. In
> fact, more pots seemed to be ruined. Last night, I
> fired slow and to cone 6. OH MY GOODNESS, almost
> EVERYTHING was totally covered with creators - inside
> and out - top and bottom. I had re-fired some things
> that only had a few bubbles and now they are
> completely full of bubbles.
>
> The glazes are not too thick because even the thinest
> of glaze has teeny tiny creators. I've never really
> had a problem before, but now it's out of control.
>
> When I begin firing, I leave the vents open and the
> lid propped. My kiln has 6 switches that have to be
> flipped from the bottom up. Without going through my
> complete firing schedule, I'll just say that I
> gradually turn up the kiln one switch at a time. I
> close the lid after I flip the second switch and close
> the vents all but the top one. I close the top vent
> after the next switch.
>
> Any help would be greatly appreciated. Thank you in
> advance.
>
> GEM
>
Chris Jones on sat 9 mar 02
Hello,
I just read your post and had and solved the "similar" problems you "may" be
having. Since there are several variables involved here, I hesitate to claim
my problems were caused by the same factors as yours. I had been firing to
^6 electric and getting good results with a little bit of cratering here and
there. Not really acceptable, but I lived with the few I got. Then one day,
a whole load went crazy! Craters all over the place. I didn't change a thing
about how I fired or glazed but it happened and kept happening in the next
couple of firings. What I did not expect is that my supply of Gerstley
Borate had changed and most likely that was my culprit (not positive). It
was the only variable in the whole mess. I reduced the firing a cone and the
problem (craters) were gone and the glaze was just like it should be.
Soooooooooooo, if you make your own glazes, consider the ingredients can be
slightly different bag to bag. As others have mentioned (in a much more
concise post) try firing a cone lower, wash your bisque, screen your glazes,
and use watch cones to double check your firings. I hope all this will help
and you didn't fall asleep reading my ramblings.
Thank you,
Chris Jones
Visit www.jonespottery.net
MartinDEpstein on sat 9 mar 02
I t sounds like the clay is bloating-possibly over fired. Try a lower
temperature firing. =
pottershands@JUNO.COM on sun 10 mar 02
Here are a few more details:
I haven't been using witness cones - but, I'll start.
I had been bisque firing to cone 04, but lately I've been firing to cone
06.
I'm using commercial glazes.
The kiln has three vents & 6 switches.
I turn up the kiln by flipping the bottom switch first and then I go up
from there.
When I glaze fired to cone 5, only the bottom pots, and the bottom of the
pots on the middle shelf, had creators. This made me think that the
bottom of the kiln was getting too hot, too fast. But, everyone has told
me that the top of an electric kiln is the hottest. So, I thought maybe
the kiln wasn't hot enough and glaze fired to cone 6. That was
disastrous.
A really big help would be if some of you would tell me your glaze firing
schedule and how long it takes.
Thanks to all of your for your help.
GEM
Snail Scott on sun 10 mar 02
At 10:11 AM 3/10/02 -0500, you wrote:
This made me think that the
>bottom of the kiln was getting too hot, too fast. But, everyone has told
>me that the top of an electric kiln is the hottest.
T'aint necessarily so. Though it's often the case
that electric kilns fire hotter on the top level,
you can't really assume it for your particular
kiln and elements. Put witness cones on every
shelf. You don't have to be able to see them,
but when you unload after the firing, you can
see what temperature every shelf reached. Not
necessary to do this every time you fire, but if
you start getting weird results that vary by
shelf, it might be worth checking.
-Snail
Ababi on sun 10 mar 02
What are you meaning creators?
Does the clay bloat?
Is it overfire?
Perhaps you should use a wider rang glaze?
Ababi Sharon
Kibbutz Shoval- Israel
Glaze addict
ababisha@shoval.org.il
http://members4.clubphoto.com/ababi306910/
http://www.milkywayceramics.com/cgallery/asharon.htm
http://www.israelceramics.org/
---------- Original Message ----------
>Here are a few more details:
>I haven't been using witness cones - but, I'll start.
>I had been bisque firing to cone 04, but lately I've been firing to cone
>06.
>I'm using commercial glazes.
>The kiln has three vents & 6 switches.
>I turn up the kiln by flipping the bottom switch first and then I go up
>from there.
>When I glaze fired to cone 5, only the bottom pots, and the bottom of
>the
>pots on the middle shelf, had creators. This made me think that the
>bottom of the kiln was getting too hot, too fast. But, everyone has told
>me that the top of an electric kiln is the hottest. So, I thought maybe
>the kiln wasn't hot enough and glaze fired to cone 6. That was
>disastrous.
>A really big help would be if some of you would tell me your glaze
>firing
>schedule and how long it takes.
>Thanks to all of your for your help.
>GEM
>________________________________________________________________________
>______
>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.
Greg Lamont on sun 10 mar 02
GEM,
I usually don't have a problem with "creators", I try to think of myself as
one, so I assume by "creators", you mean "craters" (blisters). I've fired
to cone 6 in an electric kiln for a few years now. My kiln is equipped with
an Orton stand vent system and is computerized. My glazes, except for one,
have benefited from firing to cone 5 with a 30 minute soak and then a slow
cool down--about 150 degrees F. per hour, to allow for the clay and/or glaze
to finish outgassing and to smooth over. The only glaze I still have
problems with is an iron saturate glaze that still has a few very tiny
blisters no matter what I do firing-wise, so I'm planning on experimenting
with a different base glaze.
Greg
-----Original Message-----
From: pottershands@JUNO.COM
To: CLAYART@LSV.CERAMICS.ORG
Date: Saturday, March 09, 2002 4:30 AM
Subject: cone 5/6 firing - HELP!!!
>Please, I need some suggestions right away.
>
>I am having an awful time with creators. My pots are
>completely covered, inside and out with them.
>
>I first started noticing them on the underside of
>several pots in the middle of the kiln and on the top
>and bottom of the pots on the bottom of the kiln.
>
>I've been firing to cone 5. At one time, most of my
>pots turned out pretty good with only a few blisters
>or creators here and there. I've been trying to figure
>out why. I tried firing slower. That didn't help. In
>fact, more pots seemed to be ruined. Last night, I
>fired slow and to cone 6. OH MY GOODNESS, almost
>EVERYTHING was totally covered with creators - inside
>and out - top and bottom. I had re-fired some things
>that only had a few bubbles and now they are
>completely full of bubbles.
>
>The glazes are not too thick because even the thinest
>of glaze has teeny tiny creators. I've never really
>had a problem before, but now it's out of control.
>
>When I begin firing, I leave the vents open and the
>lid propped. My kiln has 6 switches that have to be
>flipped from the bottom up. Without going through my
>complete firing schedule, I'll just say that I
>gradually turn up the kiln one switch at a time. I
>close the lid after I flip the second switch and close
>the vents all but the top one. I close the top vent
>after the next switch.
>
>Any help would be greatly appreciated. Thank you in
>advance.
>
>GEM
>
>___________________________________________________________________________
___
>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.
>
Ababi on mon 11 mar 02
Will you give me the recipe? I love crater glazes?
I might even cure it for you
Ababi
---------- Original Message ----------
>In a message dated Sun, 10 Mar 2002 3:05:12 PM Eastern Standard Time,
>Ababi writes:
>> What are you meaning creators?>>
>I think he means "craters", those terrible sharp edged holes in the
>glaze that remind me of acne.
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