Frank Gaydos on sun 18 jul 99
We are running a figurative sculpture class this summer session. The
instructor wants to fire the sculptures solid. I would guesstimate 5-6
inches thick.
Has anyone had experience with this thickness of clay? We have about twenty
students.
I realize I'll have to candle them, but, for how long? At least overnight I
know.
How can I tell when it will be safe to start ramping up the temperature? If
I do not spot any more moisture given off?
I'm using electric kilns.
TIA
Frank Gaydos
510 Gerritt St.
Philadelphia,Pa.
19147-5821 USA
fgaydos@erols.com
http://www.erols.com/fgaydos
http://members.xoom.com/fgaydos/index.html
Linda Blossom on mon 19 jul 99
Hello Frank,
It is a shame that you are not firing with gas. I always feel better with
the draft when I am firing very thick pieces since it can carry the moisture
away. I would usually candle overnight in my gas kiln - about 10 hours.
However, in electric, I would dry them thoroughly under room conditions and
then put them out in the sun for a day and then candle them for at least
overnight, but probably about 12 hours. I learned to go up at 75 degrees
centigrade per hour when I was firing pieces that were about 3" thick. My
usual 120 degrees per hour was causing cracking. If I were doing thicker
pieces than that in electric, I would go about 50 degrees an hour until all
the molecular water was driven off - isn't that about 700 centigrade? Then I
would go up at 75 per hour.
Linda Blossom
2366 Slaterville Rd
Ithaca, NY 14850
607-539-7912
blossom@twcny.rr.com
-----Original Message-----
From: Frank Gaydos
To: CLAYART@LSV.UKY.EDU
Date: Sunday, July 18, 1999 1:49 PM
Subject: Thick work
>----------------------------Original message----------------------------
>We are running a figurative sculpture class this summer session. The
>instructor wants to fire the sculptures solid. I would guesstimate 5-6
>inches thick.
>Has anyone had experience with this thickness of clay? We have about twenty
>students.
> I realize I'll have to candle them, but, for how long? At least overnight
I
>know.
>How can I tell when it will be safe to start ramping up the temperature? If
>I do not spot any more moisture given off?
>I'm using electric kilns.
>TIA
>Frank Gaydos
>510 Gerritt St.
>Philadelphia,Pa.
>19147-5821 USA
>
>fgaydos@erols.com
>http://www.erols.com/fgaydos
>http://members.xoom.com/fgaydos/index.html
>
Tom Wirt on mon 19 jul 99
Frank,
I'll be interested in replies you get on this. I've got a friend having
lots of problems with pieces up to an inch thick. I haven't seen the
cracking, but he's firing slowly and drying for months before firing. I'm
wondering if he's having his problems with cooling too fast? I would assume
a moisture burst would have the telltale smooth on one side, rough on the
other. If it's cooling, the chunks would have booth sides intact.??? Any
experience out there on this?
Tom Wirt
From: Frank Gaydos
Subject: Thick work
> ----------------------------Original message----------------------------
> We are running a figurative sculpture class this summer session. The
> instructor wants to fire the sculptures solid. I would guesstimate 5-6
> inches thick.
> Has anyone had experience with this thickness of clay? We have about
twenty
> students.
Phyllis E. Tilton on mon 19 jul 99
Frank: I am surprised that the instructor would risk all the work that could
be in that kiln chancing that one would blow and damage all else. If they
have not been taught to cut the sculpture, clean or hollow out, and put them
back together, that is a problem. If the work is still soft enough to get a
long needle tool-may have to be a very long darning needle to let it vent
some of the moisture. Even then, they need to sit for a VERY long period of
time to really dry.
A friend of mine that lives in a condo, can't have a kiln so I fired for her
for a long time. She works very fast and often worked very thick. Her pieces
are wonderful-showing movement, emotion, style and any other adjective. I
would plead with her to use the needle tool and let them dry even longer.She
sprayed her finishes on the bisqued pieces, so the holes would not be seen. I
never put any of my work in the kiln at the same time because they did often
blow--and I did take a long time to fire them. She would tell me that they
had dried for a month or so. She did find someone else to fire for her-a
realy handsome young man(I am old enough to be her mother) so we are still
good friends. I did not charge her because she wanted to pay me in her work.
Her stuff sells for $300 and up so I have some valuable pieces that I
treasure.
Phyllis Tilton
Daisypet@aol.com
tmartens on mon 19 jul 99
Frank you will have to give them a goodly time to dry before going
anywhere near the kiln, the moisture inside takes it's own sweet time to
go. I have had stuff explode at 850C, however if completely dry, I don't
bisque particularly slowly.
Toni of that far away place
> ----------------------------Original message----------------------------
> We are running a figurative sculpture class this summer session. The
> instructor wants to fire the sculptures solid. I would guesstimate 5-6
> inches thick.
> Has anyone had experience with this thickness of clay? We have about twenty
> students.
> I realize I'll have to candle them, but, for how long? At least overnight I
> know.
> How can I tell when it will be safe to start ramping up the temperature? If
> I do not spot any more moisture given off?
> I'm using electric kilns.
> TIA
> Frank Gaydos
> 510 Gerritt St.
> Philadelphia,Pa.
> 19147-5821 USA
>
> fgaydos@erols.com
> http://www.erols.com/fgaydos
> http://members.xoom.com/fgaydos/index.html
nikom chimnok on tue 20 jul 99
Hello Frank,
If I were faced with this problem, my first question would be, "What
is the claybody?" It makes all the difference in the world. If it's loaded
up with grog and talc and/or wollastonite or some such anti-thermal shock
material, or if it's got some organic in it--rice husks, sawdust,
paper--then there's a chance you can fire it without going to extremes.
On the other hand, I just supervised a firing of thick pieces made
from throwing clay. I told the manager of my factory he was stupid to even
try, but he said he wanted to see the results, so I made a schedule that
held it under 100 C for 8 hours, then 25 degrees per hour for another
8--took a total of 30 hours to 1050 (cone 04). The result: about 4 of the 25
pieces had small explosions (around 225 degrees) and all but 5 of the rest
had big wide open firing cracks. Totally predictable.
On the other hand, I've fired pieces of similar thickness in 12
hours, start to finish, with no damage, with clay that I mixed specially for
the purpose, as described above.
I guess any clay of any thickness can be fired successfully, if
you've got the time--but it might take 10 days or even a month. I believe I
remember that the flawed main lense for the Hubble telescope was fired for a
year, in a special rotating kiln whose centrifigal force threw the glass
ever outward, making the edges thicker than the center, so that it didn't
need so much grinding. So if you have any problem with this load, ask NASA
to help with your next one.
Good luck,
Nikom in Thailand, where we are experts in using kilns to destroy works of art
**********************************************************
From: Frank Gaydos
Subject: Thick work
----------------------------Original message----------------------------
We are running a figurative sculpture class this summer session. The
instructor wants to fire the sculptures solid. I would guesstimate 5-6
inches thick.
Has anyone had experience with this thickness of clay? We have about
twenty
students.
Russel Fouts on tue 20 jul 99
>> I'll be interested in replies you get on this. <<
Solid is an old jazz expression meaning cool, same in French. And solid
IS really cool. There isn't much that's cooler than seeing the
expression on someone's face when they pick up a solid piece and
discover how heavy it is, especially when it doesn't look as heavy as it
is. I really became fascinated by making and firing really heavy or
solid pieces after buying a small solid sculpture by NZ'er Tony Bond at
the Biennial in Andenne. I've even sold some REALLY heavy bowls and
solid "bowls" to quite enthusistic people. People who saw my slide
presentation in the international slide show saw one of my "flowers".
Richard Zakin has a section on solid forming in his book, can't remember
if it tells how to fire them.
Paperclay works well for this but is not necessary, it cracks less in
the drying but cracking is part of THIS process. I don't want them to
crack enough to fall apart.
The pieces are dried slowly then once dry sit for a few days on top of
the water heater or the kiln if it's firing before going into the kiln.
I take it slowly up to 100c (boiling point of water) and leave it there
overnight. Then I go up slowly to red heat and hold for a few hours.
There is a temperature somewhere around there where the molecular water
burns off. Then, supposedly, you SHOULD be able to take it up as fast as
you like. I've never been that brave but do go up only a little slower
then normal to 1000c which is the max temperature I fire to. I've never
burst anything doing this.
Russel
Frank Gaydos on wed 21 jul 99
We are running a figurative sculpture class this summer session. The
instructor wants to fire the sculptures solid. I would guesstimate 5-6
inches thick.
Has anyone had experience with this thickness of clay? We have about twenty
students.
> ----------------------------Original message----------------------------
> Hello Frank,
> If I were faced with this problem, my first question would be,
"What
> is the claybody?" It makes all the difference in the world. If it's loaded
> up with grog and talc and/or wollastonite or some such anti-thermal shock
> material, or if it's got some organic in it--rice husks, sawdust,
> paper--then there's a chance you can fire it without going to extremes.
You are right of course Nikom,
I forgot to mention the claybody. It is a terracotta all purpose. I decided
to add 6% medium grog to try and open it up a little. That is in addition to
4% fine grog. I'm hoping to convince the instructor to instruct the students
to 'scoop' the bottoms, even a little,to give them a fighting chance. (They
are working from a live model in a reclining position).
I plan on soaking the work all day, all night and late into the second
day....then take it from there.
They only use about 200 pounds of clay (so far) a class so it will be easy
to reformulate on the fly.
I'll let you know how it works out and thanks to all who helped with this
question.
Janet Kaiser on thu 22 jul 99
As I understand the original question, someone wants to fire work 5-6 inches
thick made by students on a short summer course?
Well, quite honestly, I think it is being very unfair to the students. They =
will
put a lot of work into something which may just work if heavily grogged, =
paper
clay or added straw, etc. and a long, long drying time. However, more than
likely it will not be successful and all that time and effort will be =
wasted.
I was really disgusted when a friend of mine went on just such a course. The
=22teacher=22 either did not know any of the finer points or did not tell =
the
students about =22the basics=22 of sculpting in clay. She even had them =
=22carving=22
dried up slip out of the bottom of bins scrounged from a workshop=21 Not one
single piece from that course survived the firing... Twelve would-be =
enthusiasts
were =22killed-off=22 in one fell swoop. That was not teaching... and yet =
she held
these courses for some years=21=21=21 Word eventually spread and her classes=
refused
to use clay=21
It also accounts for most potters in this area refusing to fire work they =
have
not supervised from start to finish themselves... They had all run the =
gauntlet
of that =22teacher=22 with some pretty predictable consequences. Needless to=
say,
she always blamed the potter and the firing=21=21
Janet Kaiser
The Chapel of Art, Criccieth LL52 0EA, GB-Wales
Home of The International Potters Path
WEB SITE: http://www.the-coa.org.uk
EMAIL: postbox=40the-coa.org.uk
Iveragh Ceramics on fri 23 jul 99
Dear Janet,
Providing one lets pieces dry thoroughly and then fire
them very slowly there should be no losses.We have a retreat here for
art/crafts and as yet the centre has no ceramic facilities so the potters
have been bringing their work to me for firing,the next resident may be a
painter or poet or whatever who finds a bag of clay and makes something
solid,often much more than five inches, which is again brought to me for
firing. I do explain that there is a possibility,depending on my
impatience,that it may explode.So far so good,none have exploded.
Regards,
Bob Hollis
P.S When I write here I mean this locality and if anyone is interested here
is the address to apply.
The Secretary,
Cill Rialaig Project,
Ballinskelligs,
Co.Kerry,
Rep.of Ireland Tel/
++353-66-9479297
----- Original Message -----
From: Janet Kaiser
To:
Sent: 23 July 1999 00:14
Subject: Thick work
----------------------------Original message----------------------------
As I understand the original question, someone wants to fire work 5-6 inches
thick made by students on a short summer course?
Well, quite honestly, I think it is being very unfair to the students. They
will
put a lot of work into something which may just work if heavily grogged,
paper
clay or added straw, etc. and a long, long drying time. However, more than
likely it will not be successful and all that time and effort will be
wasted.
I was really disgusted when a friend of mine went on just such a course. The
"teacher" either did not know any of the finer points or did not tell the
students about "the basics" of sculpting in clay. She even had them
"carving"
dried up slip out of the bottom of bins scrounged from a workshop! Not one
single piece from that course survived the firing... Twelve would-be
enthusiasts
were "killed-off" in one fell swoop. That was not teaching... and yet she
held
these courses for some years!!! Word eventually spread and her classes
refused
to use clay!
It also accounts for most potters in this area refusing to fire work they
have
not supervised from start to finish themselves... They had all run the
gauntlet
of that "teacher" with some pretty predictable consequences. Needless to
say,
she always blamed the potter and the firing!!
Janet Kaiser
The Chapel of Art, Criccieth LL52 0EA, GB-Wales
Home of The International Potters Path
WEB SITE: http://www.the-coa.org.uk
EMAIL: postbox@the-coa.org.uk
Janet Kaiser on sun 25 jul 99
-----Original Message-----
From: Iveragh Ceramics
To: CLAYART@LSV.UKY.EDU
Date: 23 July 1999 23:42
Subject: Re: Thick work
>----------------------------Original message----------------------------
>Dear Janet,
> Providing one lets pieces dry thoroughly and then fire
>them very slowly there should be no losses.We have a retreat here for
>art/crafts and as yet the centre has no ceramic facilities so the potters
>have been bringing their work to me for firing,the next resident may be a
>painter or poet or whatever who finds a bag of clay and makes something
>solid,often much more than five inches, which is again brought to me for
>firing. I do explain that there is a possibility,depending on my
>impatience,that it may explode.So far so good,none have exploded.
> Regards,
> Bob Hollis
>P.S When I write here I mean this locality and if anyone is interested here
>is the address to apply.
> The Secretary,
> Cill Rialaig Project,
> Ballinskelligs,
> Co.Kerry,
> Rep.of Ireland Tel/
>++353-66-9479297
>----- Original Message -----
>From: Janet Kaiser
>To:
>Sent: 23 July 1999 00:14
>Subject: Thick work
>
>
>----------------------------Original message----------------------------
>As I understand the original question, someone wants to fire work 5-6
inches
>thick made by students on a short summer course?
>
>Well, quite honestly, I think it is being very unfair to the students. They
>will
>put a lot of work into something which may just work if heavily grogged,
>paper
>clay or added straw, etc. and a long, long drying time. However, more than
>likely it will not be successful and all that time and effort will be
>wasted.
>
>I was really disgusted when a friend of mine went on just such a course.
The
>"teacher" either did not know any of the finer points or did not tell the
>students about "the basics" of sculpting in clay. She even had them
>"carving"
>dried up slip out of the bottom of bins scrounged from a workshop! Not one
>single piece from that course survived the firing... Twelve would-be
>enthusiasts
>were "killed-off" in one fell swoop. That was not teaching... and yet she
>held
>these courses for some years!!! Word eventually spread and her classes
>refused
>to use clay!
>
>It also accounts for most potters in this area refusing to fire work they
>have
>not supervised from start to finish themselves... They had all run the
>gauntlet
>of that "teacher" with some pretty predictable consequences. Needless to
>say,
>she always blamed the potter and the firing!!
>
>Janet Kaiser
>
>
>The Chapel of Art, Criccieth LL52 0EA, GB-Wales
>Home of The International Potters Path
>WEB SITE: http://www.the-coa.org.uk
>EMAIL: postbox@the-coa.org.uk
>
Yes, Bob!
You are quite right about the drying. What I was trying to point out in my
tin-pot sort of way, was that short summer courses do not allow for is
drying out enough.
Also it seems sort of silly to old fashioned me to "teach" methods that
break the rules. First get the basics right and then go pushing to new
frontiers. I still think it is unfair to have people working hard on
something which perhaps/may/probably bust in the firing.
In your situation, where people have just had a go and are not primarily
there to make sculptures, they will not suffer dreadful disappointment if it
does not work out. In the situation where you are spending good money and
probably taking precious holiday time/days to learn a skill, I do not think
they will be so sanguine about taking ceramic shards home to maybe stick
together with super glue.
Just my opinion.
Janet
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