Liz Holden on fri 31 jul 98
I'm new to the clayart newsgroup and would like to know if any one can help =
with
problems regarding firing. I fire earthenware moulded pieces to cone 06,
followed by a glaze firing of cone 02. I've recently developed problems with=
the
wares on my first 3 shelves. The glaze seems to be peeling off, I've put It =
down
to a number of problems: 1- Too much silicate in my clay mix. 2. Faulty =
elements
in the lower part of the kiln. 3. To much paint.
All my paints are underglazes (Mayco, duncan, Amaco), and I use a =
transparent
glaze.
Any help or suggestions would be appreciated.
Yours in pottery
Liz Holden.
Liz Holden on sun 2 aug 98
Hi Judith,
I purchase the glaze powder locally and it's firing range is 1080 - 1120
Celsius. I've never had a major problem before and have been using this =
glaze
for 8 years now. The name of it is K300. I mix 1kg powder to 2litres water. =
So,
do you have any suggestions.
Liz
South Africa
Diane G. Echlin on sun 23 apr 00
Ugh. Why does this happen right before a show!?!
I am using Sheffield Pottery ^6-10 white stoneware,
bisqued to ^06 in a computerized electric kiln. I'm
having several problems.
1. The kiln has been fired a maximum of 20 times...it
isn't very old. Some of the elements have sagged a bit
after the last time I moved, and I used pins bent in a "U"
shape to keep them at least nearer to their grooves, as
advised by several people on the list. However, for the
last 3 times I fired to ^6, I have gotten an error message
that I looked up in the manual. It says that the kiln was
not ramping up according to the preset program, that it
was firing slower, and thus the error message. The first
2 times I got this message, the pots all looked great, with
no flaws (well, not firing flaws) The kiln has not errored
out when firing bisque or to ^03. To the best of my
knowledge, the wiring from the panel to the kiln is adequate,
and I know of no "brown-outs" occurring during firing.
2.I am using the lovely Blue Hare's fur glaze that I found
here on Clayart, but this time most of my pieces have
significant pin holing. That is to say, the pinholes are not
numerous, but the few that are there are very well defined.
Due to the small amount of glaze I had on hand, I poured
instead of dipped (not my favorite application method)
Are the pinholes caused by an incomplete firing? Too fast
a cool down? Too low a bisquing? Poor application?
(yes, I wipe the pieces down prior to glazing) Argh!
3. I've read through the archives on pin holing and refiring,
and the basic advice is to warm the piece, put dots of raw
glaze in the pinholes, refire VERRRY slowly, either to the
same cone or 1 cone lower (which is it?) and pray. Is there
anything else I should do?
Sorry for the long descriptions, but I wanted to be as detailed
as possible.
Thanks in advance for your help!
Di (if I wanted to live in Seattle I would have moved there....
what's the deal with all this rain???)
Cindy Strnad on mon 24 apr 00
Di,
Sorry, but I'll bet you need new elements. Euclids is very fast, in my
experience. Their number is 1-800-296-5456. Sometimes the elements that come
with your kiln are substandard. Mine certainly were. Another thing that
could be wrong is that one of your relays may not be functioning. They're
simple to replace, though not always conveniently located.
Look carefully at all your elements and see if there are any breaks. If you
have an electric meter, use it to test each element. I don't have a meter,
and I can't seem to keep it in my head how to use one, so I place a bit of
dry grass so that it touches the element I want to test, then turn on the
kiln. If it smokes, the element is getting power--it's not the relay, and
the element is not broken. It may still be in need of replacement, however.
If you establish that all your elements are functioning, I'd order a new set
of elements, and order the heaviest ones that can be used with the kiln.
Euclids can help you with that.
As for the pinholes, you can get them from not firing quite high enough--I
have, I know, at times when my kiln has failed to reach temperature. You can
also get them when your glaze is on too thick, as it is likely to be with
pouring. Glaze application method is very, very important. Make some more
glaze so you can follow your normal procedure of dipping. You may be able to
get rid of the pinholes by firing again, or you may make them worse. You
need to increase temperature slowly because the work is now much more
vitreous and gasses trying to escape may cause blow-ups if you go too fast.
Hope this is of help to you,
Cindy Strnad
earthenv@gwtc.net
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
David Woodin on mon 24 apr 00
The only way to tell what happened is to always use witness cones.
Unfortunately the advertisments for computor controls lead us to believe all
firing problems are now solved and there is no need to use cones or safety
devices. Take a hint from industry and use cones. Instead of losing another
load repeat the firing using the same shelf set up and some kiln furniture
and witness cones.
David
Chris Schafale on tue 25 apr 00
No idea why Blue Hare's Fur/Floating Blue pinholes, but it does
consistently for me too. My opinion on refiring -- don't bother,
because it comes out looking overfired, changes color, blisters,
does other weirdness. And the pinholes don't go away. If you
must use this glaze (and believe me, I understand the addiction),
learn to live with pinholes. If you insist on trying it, definitely refire
a cone lower.
Your mileage may vary, and probably will, knowing this glaze.
And yes, these things always seem to happen right before a
show....
Chris
with a show coming up on Saturday and just having gotten the kiln
put back together and restarted, hoping the vent is OK
> ----------------------------Original message----------------------------
> Ugh. Why does this happen right before a show!?!
>
> I am using Sheffield Pottery ^6-10 white stoneware,
> bisqued to ^06 in a computerized electric kiln. I'm
> having several problems.
>
> 1. The kiln has been fired a maximum of 20 times...it
> isn't very old. Some of the elements have sagged a bit
> after the last time I moved, and I used pins bent in a "U"
> shape to keep them at least nearer to their grooves, as
> advised by several people on the list. However, for the
> last 3 times I fired to ^6, I have gotten an error message
> that I looked up in the manual. It says that the kiln was
> not ramping up according to the preset program, that it
> was firing slower, and thus the error message. The first
> 2 times I got this message, the pots all looked great, with
> no flaws (well, not firing flaws) The kiln has not errored
> out when firing bisque or to ^03. To the best of my
> knowledge, the wiring from the panel to the kiln is adequate,
> and I know of no "brown-outs" occurring during firing.
>
> 2.I am using the lovely Blue Hare's fur glaze that I found
> here on Clayart, but this time most of my pieces have
> significant pin holing. That is to say, the pinholes are not
> numerous, but the few that are there are very well defined.
> Due to the small amount of glaze I had on hand, I poured
> instead of dipped (not my favorite application method)
> Are the pinholes caused by an incomplete firing? Too fast
> a cool down? Too low a bisquing? Poor application?
> (yes, I wipe the pieces down prior to glazing) Argh!
>
> 3. I've read through the archives on pin holing and refiring,
> and the basic advice is to warm the piece, put dots of raw
> glaze in the pinholes, refire VERRRY slowly, either to the
> same cone or 1 cone lower (which is it?) and pray. Is there
> anything else I should do?
>
> Sorry for the long descriptions, but I wanted to be as detailed
> as possible.
> Thanks in advance for your help!
> Di (if I wanted to live in Seattle I would have moved there....
> what's the deal with all this rain???)
>
Light One Candle Pottery
Fuquay-Varina, North Carolina, USA
(south of Raleigh)
candle@intrex.net
http://www.lightonecandle.com
Penny P on thu 29 apr 04
Hello Any and Everyone
I am having serious firing problems and have run out of people to call so,
here I am.
I have a 2 year old Olympic Kiln that has a sitter, no timer or controller.
I have had nothing but problems with this thing.
After repeated over firings. I replaced the tube assembly in Dec 03
(ceramic tube was bowed??) Things went smoothly for about 6-7 firings,
now it either wont go up to a ^05, fires beautifully or it fires through
the roof !!Tuesday during a ^5 firing, it fired to the point that the cone
turned to glass and all the clay bubbled! That was the last straw. Can
anyone even begin to help with this?
Thanks in advance,
Penny P
Arnold Howard on fri 30 apr 04
Penny, have you checked the movement of the actuating rod in the Kiln
Sitter? It should move freely.
Have you checked the adjustment of the Kiln Sitter with a firing gauge?
Everyone who has a Kiln Sitter should have a firing gauge.
Place witness cones on the shelf and watch them through the peephole as the
kiln gets closer to the shutoff time. You will know precisely when to shut
off the kiln if you can see the cones.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
arnoldhoward@att.net
----- Original Message -----
From: "Penny P"
> I have a 2 year old Olympic Kiln that has a sitter, no timer or
controller.
> I have had nothing but problems with this thing.
> After repeated over firings. I replaced the tube assembly in Dec 03
> (ceramic tube was bowed??) Things went smoothly for about 6-7 firings,
> now it either wont go up to a ^05, fires beautifully or it fires through
> the roof !!Tuesday during a ^5 firing, it fired to the point that the cone
> turned to glass and all the clay bubbled! That was the last straw. Can
> anyone even begin to help with this?
MarjB on sat 1 may 04
Morning Penny
You do not mention in your post if you are using large viewing cone packs.
If not..do...must do. The kiln sitter/cone holder is only a back up but is
not to be relied upon to guage temp of kiln. You need to view the cones
through the peep holes during firing. So many factors influence the firing
time of the kiln - load density - element life - stack configuration etc.
Large pyrometric cones in a pack visable through peep holes will tell you
what is happening during a firing. My apologies if this is something you do
and I mis-understood your post. MarjB
----- Original Message -----
From: "Penny P"
To:
Sent: Thursday, April 29, 2004 9:57 PM
Subject: Firing Problems
> Hello Any and Everyone
>
> I am having serious firing problems and have run out of people to call so,
> here I am.
> I have a 2 year old Olympic Kiln that has a sitter, no timer or
controller.
> I have had nothing but problems with this thing.
> After repeated over firings. I replaced the tube assembly in Dec 03
> (ceramic tube was bowed??) Things went smoothly for about 6-7 firings,
> now it either wont go up to a ^05, fires beautifully or it fires through
> the roof !!Tuesday during a ^5 firing, it fired to the point that the cone
> turned to glass and all the clay bubbled! That was the last straw. Can
> anyone even begin to help with this?
> Thanks in advance,
> Penny P
>
>
____________________________________________________________________________
__
> 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.
>
Penny P on mon 3 may 04
Good Morning Marj and thank you for your post,
I don't use viewing cones, I wasn't taught to do this. A gentleman emailed
me and told me to try it and explained how to use them. I will try it.
Although, I dont think this explains why the kiln is not getting up in
temp. sometimes, but ok other times. Its trial and error!
Thanks for your response.
Penny
> [Original Message]
> From: MarjB
> To:
> Date: 4/30/2004 12:46:00 PM
> Subject: Re: Firing Problems
>
> Morning Penny
>
> You do not mention in your post if you are using large viewing cone
packs.
>
> If not..do...must do. The kiln sitter/cone holder is only a back up but
is
> not to be relied upon to guage temp of kiln. You need to view the cones
> through the peep holes during firing. So many factors influence the firing
> time of the kiln - load density - element life - stack configuration etc.
> Large pyrometric cones in a pack visable through peep holes will tell you
> what is happening during a firing. My apologies if this is something you
do
> and I mis-understood your post. MarjB
>
> ----- Original Message -----
> From: "Penny P"
> To:
> Sent: Thursday, April 29, 2004 9:57 PM
> Subject: Firing Problems
>
>
> > Hello Any and Everyone
> >
> > I am having serious firing problems and have run out of people to call
so,
> > here I am.
> > I have a 2 year old Olympic Kiln that has a sitter, no timer or
> controller.
> > I have had nothing but problems with this thing.
> > After repeated over firings. I replaced the tube assembly in Dec 03
> > (ceramic tube was bowed??) Things went smoothly for about 6-7 firings,
> > now it either wont go up to a ^05, fires beautifully or it fires through
> > the roof !!Tuesday during a ^5 firing, it fired to the point that the
cone
> > turned to glass and all the clay bubbled! That was the last straw. Can
> > anyone even begin to help with this?
> > Thanks in advance,
> > Penny P
> >
> >
>
____________________________________________________________________________
> __
> > 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.
Penny P on mon 3 may 04
Thank you Arnold,
I have had replies saying the viewing cones would be a good idea, although
the kiln wont even go up enough to bend a sitter cone then sometimes it's
fine?
I replaced the kiln sitter and tube assembly, adjusted it and all went well
for 5-6 firings. How often should the sitter be adjusted?
Penny
> [Original Message]
> From: Arnold Howard
> To:
> Date: 4/30/2004 10:43:28 AM
> Subject: Re: Firing Problems
>
> Penny, have you checked the movement of the actuating rod in the Kiln
> Sitter? It should move freely.
>
> Have you checked the adjustment of the Kiln Sitter with a firing gauge?
> Everyone who has a Kiln Sitter should have a firing gauge.
>
> Place witness cones on the shelf and watch them through the peephole as
the
> kiln gets closer to the shutoff time. You will know precisely when to shut
> off the kiln if you can see the cones.
>
> Sincerely,
>
> Arnold Howard
> Paragon Industries, L.P., Mesquite, Texas USA
> arnoldhoward@att.net
>
> ----- Original Message -----
> From: "Penny P"
> > I have a 2 year old Olympic Kiln that has a sitter, no timer or
> controller.
> > I have had nothing but problems with this thing.
> > After repeated over firings. I replaced the tube assembly in Dec 03
> > (ceramic tube was bowed??) Things went smoothly for about 6-7 firings,
> > now it either wont go up to a ^05, fires beautifully or it fires through
> > the roof !!Tuesday during a ^5 firing, it fired to the point that the
cone
> > turned to glass and all the clay bubbled! That was the last straw. Can
> > anyone even begin to help with this?
>
>
____________________________________________________________________________
__
> 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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