Clay art on fri 24 aug 12
I can fully agree with Vince on this. I have seen splinters of glass =3D
coming
loose from a glazed bowl. It may not happen immediately after the =3D
firing,
but it will happen. =3D20
I have seen potters putting glass on lids, but it is in my opinion best =3D
to
avoid it altogether.=3D20
Antoinette Badenhorst
www.porcelainbyAntoinette.com
-----Original Message-----
From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of Vince =3D
Pitelka
Sent: Friday, August 24, 2012 5:54 PM
To: Clayart@LSV.CERAMICS.ORG
Subject: Re: adding ground glass to bowls
Susan Fox Hirschmann wrote:
I have a new student, with a background in fused glass, that would like =3D
to
add ground glass to the bottom of some of her small bowls, during the =3D
glaze
firing.
I occasionally read bits and pieces about doing such things, even
remembering Vince commenting about not creating these pieces and selling
them as functional, for the inherent dangers of glass dislodging from =3D
the
inside bottoms. But I am wondering=3DA0how to do it, and should I even =3D
permit
her to do it? I am not one to stifle anyone's creativity and am curious =
=3D
as
to the look but not at the expensive of any kiln damage, damage to =3D
other's
work, etc."
Hi Susan. Yes, it's Vince again throwing cold water on this idea. The =3D
whole
point is that pure glass and any claybody are not a good fit, and the =3D
glass
will craze badly, and thus there is always a chance of glass fragments
coming loose. I agree that you do not want stifle anyone's creativity, =3D
but
there are health and safety issues to consider, and you cannot encourage =
=3D
a
student to do something that might be dangerous to the buyer/user. =3D
While
being a teacher who inspires innovation and creativity, you also need to =
=3D
be
a teacher who encourages the making of safe, durable wares.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net
http://iweb.tntech.edu/wpitelka/
Lee on fri 24 aug 12
Kerry has made a big business of this. We just got a Chicago Art
Institute Christmas catalog, and she has coaster in it. See her work
here:
http://www.dock6pottery.com/dock6_gallery(pottery_glass).php
--
Lee Love in Minneapolis
http://mingeisota.blogspot.com/
"Ta tIr na n-=3DF3g ar chul an tI=3D97tIr dlainn trina ch=3DE9ile"=3D97tha=
t is, "T=3D
he
land of eternal youth is behind the house, a beautiful land fluent
within itself." -- John O'Donohue
Susan Fox Hirschmann on fri 24 aug 12
I have a new student, with a background in fused glass, that would like to =
=3D
add ground glass to the bottom of some of her small bowls, during the glaze=
=3D
firing.
I occasionally read bits and pieces about doing such things, even rememberi=
=3D
ng Vince commenting about not creating these pieces and selling them as fun=
=3D
ctional, for the inherent dangers of glass dislodging from the inside botto=
=3D
ms.
But I am wondering=3DA0how to do it, and should I even permit her to do it?
I am not one to stifle anyone's creativity and am curious as to the look bu=
=3D
t not at the expensive of any kiln damage, damage to other's work, etc.
So....anyone with info about doing such a thing, some info please.
I fire ^6 oxidation.
Thanks!
Regards,
Susan
susan fox hirschmann
www.potteryart.biz
=3DA0
Vince Pitelka on fri 24 aug 12
Susan Fox Hirschmann wrote:
I have a new student, with a background in fused glass, that would like =3D
to
add ground glass to the bottom of some of her small bowls, during the =3D
glaze
firing.
I occasionally read bits and pieces about doing such things, even
remembering Vince commenting about not creating these pieces and selling
them as functional, for the inherent dangers of glass dislodging from =3D
the
inside bottoms. But I am wondering=3DA0how to do it, and should I even =3D
permit
her to do it? I am not one to stifle anyone's creativity and am curious =
=3D
as
to the look but not at the expensive of any kiln damage, damage to =3D
other's
work, etc."
Hi Susan. Yes, it's Vince again throwing cold water on this idea. The =3D
whole
point is that pure glass and any claybody are not a good fit, and the =3D
glass
will craze badly, and thus there is always a chance of glass fragments
coming loose. I agree that you do not want stifle anyone's creativity, =3D
but
there are health and safety issues to consider, and you cannot encourage =
=3D
a
student to do something that might be dangerous to the buyer/user. =3D
While
being a teacher who inspires innovation and creativity, you also need to =
=3D
be
a teacher who encourages the making of safe, durable wares.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net
http://iweb.tntech.edu/wpitelka/
Sumi von Dassow on fri 24 aug 12
Susan
my students keep wanting to do that - I discourage them but don't forbid
it. I let them do it as long as the bowl contains the glass so it
doesn't spill out (and it bubbles up some, so it can spill over the edge
of a shallow depression). I warn them it isn't functional, the surface
will craze badly, it might break the bowl in the firing, and I tell them
not to cover the bottom of the bowl with too much glass or it will
surely crack the bowl. It can work nicely on decorative flat pieces with
carved patterns, where there are no functional considerations. The glass
melts and spreads out and fills the carving. Most glass seems to keep
its color. I've never had any kiln damage of any sort, or damage to
other people's pots. It doesn't seem to spatter violently and if it
cracks the pot I think perhaps it does that during cooling so melted
glass doesn't spill out. So perhaps the apparent crazing is actually the
glass cracking under too much compression, not sure about that. One
problem is that when one person does it other people see it and want to
try it too.
Sumi
> I have a new student, with a background in fused glass, that would like t=
o add ground glass to the bottom of some of her small bowls, during the gla=
ze firing.
> I occasionally read bits and pieces about doing such things, even remembe=
ring Vince commenting about not creating these pieces and selling them as f=
unctional, for the inherent dangers of glass dislodging from the inside bot=
toms.
> But I am wondering how to do it, and should I even permit her to do it?
> I am not one to stifle anyone's creativity and am curious as to the look =
but not at the expensive of any kiln damage, damage to other's work, etc.
> So....anyone with info about doing such a thing, some info please.
> I fire ^6 oxidation.
> Thanks!
> Regards,
> Susan
> susan fox hirschmann
> www.potteryart.biz
>
>
>
John Post on fri 24 aug 12
Adding ground glass to ceramic bowls is simple. Wax an area on the
inside bottom of the bowl to prevent glaze from sticking there when
you glaze it. Then after you glaze the bowl, take small glass pieces
and place them on the waxed area inside the bowl. When the bowl is
fired the glass will melt and stick to the clay body below it. My son
and I have discovered that clear Snapple bottles work well. He likes
to add a few colored marbles to the Snapple glass to give it color.
I am using this method with my some of my students this year. The
kids will be making one functional bowl that is fully glazed, and then
use the glass as part of a decorative bowl that isn't intended to be
used with soups, cereals, ice cream etc. They're smart kids, they can
handle it.
John Post
Sterling Heights, Michigan
http://www.johnpost.us
Follow me on Twitter
https://twitter.com/UCSArtTeacher
ivor and olive lewis on sat 25 aug 12
Dear Susan Fox Hirschmann,
On the technical side, glaze and commercial glass are materials with
differing processing methods. They have different Expansion Coefficients. A
glaze may have a quartz inversion
Glass must be annealed, that is, held at a particular temperature or a
length of time. A glaze must be cooled slowly through the Quartz inversion.
Without knowledge of these times and temperature you may get serious
problems. Getting the right instructions may not be possible.
I would err on the side of caution unless you student can provide rock soli=
d
information relating to the annealing of her glass and you glazes a free
from Quartz inversions.
Sincerely,
Ivor Lewis,
REDHILL,
South Australia
Gerholdclay on sat 25 aug 12
Susan,
Second all discussions on this. Glass will crack and can do it long after =
f=3D
iring. That said if the piece is clearly nonfunctional ( and I mean can no=
t=3D
be used for food ) the effects can be beautiful. My opinion for what it =
i=3D
s worth is that bowls are a bad idea since you really can not control eve=
n=3D
tual use of a piece.
Two ways to play. One is to put glass over unfired glaze and fire together=
t=3D
o cone six. Glass will run so make sure it is contained. Glass chunks can=
b=3D
e stuck on a piece with a dab of thick glaze for vertical surfaces.
I find glazes with copper produce most brilliant color. The second way is =
t=3D
o glaze fire the piece and then add glass and fire to much lower temp. If =
I=3D
remember about 1300. You can use glass rod to make straight lines or use =
c=3D
olored glass and it will keep the color which can be very interesting agai=
n=3D
st white glaze.=3D20
Paul=3D20
Sent from my iPad
On Aug 24, 2012, at 10:50 AM, Susan Fox Hirschmann .=3D
COM> wrote:
> I have a new student, with a background in fused glass, that would like t=
o=3D
add ground glass to the bottom of some of her small bowls, during the glaz=
e=3D
firing.
> I occasionally read bits and pieces about doing such things, even remembe=
r=3D
ing Vince commenting about not creating these pieces and selling them as fu=
n=3D
ctional, for the inherent dangers of glass dislodging from the inside botto=
m=3D
s.
> But I am wondering how to do it, and should I even permit her to do it?
> I am not one to stifle anyone's creativity and am curious as to the look =
b=3D
ut not at the expensive of any kiln damage, damage to other's work, etc.
> So....anyone with info about doing such a thing, some info please.
> I fire ^6 oxidation.
> Thanks!
> Regards,
> Susan
> susan fox hirschmann
> www.potteryart.biz
> =3D20
Susan Fox Hirschmann on sat 25 aug 12
Thanks for all your responses.
I needed the reinforcement from each of you, about the dangers in functiona=
=3D
l pieces...and never knowing how these pieces may be used....and realize it=
=3D
is not the way to proceed with any student.
I do appreciate your each taking the time to respond.
Isn't clayart THE BEST?
Proliferation of great information (MOST of the time!) This time for sure!
Regards,
Susan
susan fox hirschmann
www.potteryart.biz
--- On Sat, 8/25/12, Gerholdclay wrote:
From: Gerholdclay
Subject: Re: adding ground glass to bowls
To: "Susan Fox Hirschmann"
Cc: "Clayart@LSV.CERAMICS.ORG"
Date: Saturday, August 25, 2012, 7:23 AM
Susan,
Second all discussions on this.=3DA0 Glass will crack and can do it long af=
te=3D
r firing.=3DA0 That said if the piece is clearly nonfunctional ( and I mean=
c=3D
an not be used for food ) the effects can be beautiful.=3DA0=3DA0=3DA0My op=
inion =3D
for what it is worth=3DA0 is that bowls are a bad idea since you really can=
n=3D
ot=3DA0 control eventual use of a piece.
Two ways to play.=3DA0 One is to put glass over unfired glaze and fire toge=
th=3D
er to cone six.=3DA0 Glass will run so make sure it is contained.=3DA0 Glas=
s ch=3D
unks can be stuck on a piece with a dab of thick glaze for vertical surface=
=3D
s.
I find glazes with copper produce most brilliant color.=3DA0 The second way=
i=3D
s to glaze fire the piece and then add glass and fire to much lower temp.=
=3D
=3DA0 If I remember about 1300.=3DA0 You can use glass rod to make straight=
lin=3D
es or use colored glass and it will keep the color which=3DA0 can be very i=
nt=3D
eresting against white glaze.=3D20
Paul=3D20
Sent from my iPad
On Aug 24, 2012, at 10:50 AM, Susan Fox Hirschmann =3D
.COM> wrote:
> I have a new student, with a background in fused glass, that would like t=
=3D
o add ground glass to the bottom of some of her small bowls, during the gla=
=3D
ze firing.
> I occasionally read bits and pieces about doing such things, even remembe=
=3D
ring Vince commenting about not creating these pieces and selling them as f=
=3D
unctional, for the inherent dangers of glass dislodging from the inside bot=
=3D
toms.
> But I am wondering how to do it, and should I even permit her to do it?
> I am not one to stifle anyone's creativity and am curious as to the look =
=3D
but not at the expensive of any kiln damage, damage to other's work, etc.
> So....anyone with info about doing such a thing, some info please.
> I fire ^6 oxidation.
> Thanks!
> Regards,
> Susan
> susan fox hirschmann
> www.potteryart.biz
>=3DA0=3D20
Vince Pitelka on sat 25 aug 12
Felicity Rich wrote:
All due respect to Vince, he is more knowledgeable than I, but when I was
teaching at the community college, many students over the last 8 tears have
put glass: beads, marbles or glass mosaic pieces in their pots and melted
them. I had one student melt them on her African mask. Sometimes the
results are lovely. We have never had a problem, but for the most part thes=
e
were decorative not functional.
Hi Felicity -
There is a long tradition of southeastern potters placing chunks of broken
glass atop the handles of big jars, so that the glass flows down the side o=
f
the jar in the firing. There is no reason not to use glass in this way,
because it flows and blends with the glaze. I would still only use it on
non-food-contact surfaces. The problem is in placing glass in the bottoms
of bowls so that it puddles deeply, resulting in a cracked/crazed effect
that is jewel-like in the way it reflects light. Yes, it can certainly be
appealing, but it is a gimmick, and there is the possibility of shards of
glass coming loose. My attitude has always been that it is not worth the
risk.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net
http://iweb.tntech.edu/wpitelka/
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