CJ Woodman on wed 4 aug 10
I recently discovered stained glass window making. After installing my f=
=3D
irst big=3D20
window, I want to "up the ante." So, I want to take my crystal glaze rec=
=3D
ipes=3D20
and make them into sheet glass. Any ideas?
As a potter, I make glass all the time... but only as supremely thin coat=
=3D
ings on=3D20
stoneware. None of the stained glass people make their own glass "from=3D2=
0=3D
batch," even when they have kilns! So I turn to the potters on this one.=
=3D
Has anyone ever made a sheet of crystalline glaze? Such as firing the gl=
=3D
aze on=3D20
stainless steel? I can't get the glass companies to talk to me on this, =
=3D
because=3D20
they appear to assume I'm insane as I'm spouting about feathery circles o=
=3D
f=3D20
boron surrounded by glittery threads of iron. There's very little litera=
=3D
ture on=3D20
glass with crystals grown in it. I went to the Rakow Research Library in=
=3D
=3D20
Corning, NY, and what I read was mostly on the difficulty of making coppe=
=3D
r=3D20
crystal glass, (which is just red copper reduction glaze, heh, silly glas=
=3D
s people.)=3D20=3D20
Occasionally companies produce "adventurine glass," which, according to t=
=3D
he=3D20
literature, is supposed to be like adventurine iron crystal glaze: Lots =
=3D
of little=3D20
glittering crystals. Modern samples I've seen are just metallic glitter =
=3D
embedded=3D20
in glass that's made using the "float" process, where the glass is poured=
=3D
onto=3D20
molten metal instead of cast into sheets or blocks.
I don't have access to an electronically controlled kiln right now, so te=
=3D
sting will=3D20
be laborious with a day devoted to manual temperature control. I'd apprec=
=3D
iate=3D20
any insight before I dump huge amounts of time into this idea.
Robert Harris on wed 4 aug 10
Here's some comments. Purely guesses.
You could not do it on steel as the temperatures required would
oxidise the iron. This would of course end up in your glass.
Plate (flat) glass is made by floating glass on liquid tin (I believe)
this is the Pilkington process. I'm not sure if you could do this in a
kiln environment, plus it is done at a much lower temperature. Plus in
the ordinary manufacturing process the tin never solidifies, which it
would in the context of full cooling of a kiln.
As far as I am aware all crystalline glazes craze (fairly badly),
while not a problem in a thin coating this would probably be seriously
problematic for thicker pieces - unless you find a way to separate the
cooling glass from whatever substrate it is on.
Now since I want to be constructive rather than just say "It won't
work" my suggestions would be thus.
Make some small clay trays. Fill the bottom of these with Alumina
hydrate to prevent the glaze from annealing completely to the clay.
Fill these trays with dried glaze. I would make up the glaze in the
normal way, in water, then let it dry and crush it in a pestle and
mortar - or ball mill it if you have access to one. If you want a
piece of glass 3mm thick you'll probably want a 1cm (at least) depth
of glaze material. This is a guess.
I would then fire it as normal but increase the length of time of your
top and crystal growing soaks.
Hopefully you'll get a thick piece of "glaze" in the bottom of these
trays, which won;t have annealed to badly to the clay. You'll have to
polish the side of the glaze that has been in contact with the Alumina
hydrate however.
You may be able to find a metal or something similar to "float" it on,
but I don't have any suggestions on that point (again I'd do it in a
stoneware tray). Plus you would want to do it on a very unreactive
metal. Even something like copper oxidises badly in an electric kiln
(I've done it). Lead might work, as it's boiling point is 1740C (3164F
). In theory metallic lead shouldn't get into your glass and won't
oxidise too badly, but I'm not sure what will happen when it
solidifies. As its melting point is 327C (620F) your glaze/glass
should have solidified by then.
Solder is often a tin/lead composite, so you could try floating on that.
Anyway I'm not a crystalline person and they're the real experts, but
these are my "off the top of my head" thoughts. I'll let you know if I
have any more.
Robert
On Wed, Aug 4, 2010 at 8:31 PM, CJ Woodman wrote:
> I recently discovered stained glass window making. =3DA0After installing =
my=3D
first big
> window, I want to "up the ante." =3DA0So, I want to take my crystal glaze=
r=3D
ecipes
> and make them into sheet glass. =3DA0Any ideas?
>
> As a potter, I make glass all the time... but only as supremely thin coat=
=3D
ings on
> stoneware. =3DA0None of the stained glass people make their own glass "fr=
om
> batch," even when they have kilns! =3DA0So I turn to the potters on this =
on=3D
e.
>
> Has anyone ever made a sheet of crystalline glaze? =3DA0Such as firing th=
e =3D
glaze on
> stainless steel? =3DA0I can't get the glass companies to talk to me on th=
is=3D
, because
> they appear to assume I'm insane as I'm spouting about feathery circles o=
=3D
f
> boron surrounded by glittery threads of iron. =3DA0There's very little li=
te=3D
rature on
> glass with crystals grown in it. =3DA0I went to the Rakow Research Librar=
y =3D
in
> Corning, NY, and what I read was mostly on the difficulty of making coppe=
=3D
r
> crystal glass, (which is just red copper reduction glaze, heh, silly glas=
=3D
s people.)
>
> Occasionally companies produce "adventurine glass," which, according to t=
=3D
he
> literature, =3DA0is supposed to be like adventurine iron crystal glaze: L=
ot=3D
s of little
> glittering crystals. =3DA0Modern samples I've seen are just metallic glit=
te=3D
r embedded
> in glass that's made using the "float" process, where the glass is poured=
=3D
onto
> molten metal instead of cast into sheets or blocks.
>
> I don't have access to an electronically controlled kiln right now, so te=
=3D
sting will
> be laborious with a day devoted to manual temperature control. I'd apprec=
=3D
iate
> any insight before I dump huge amounts of time into this idea.
>
--=3D20
----------------------------------------------------------
William & Susan Schran User on wed 4 aug 10
On 8/4/10 8:31 PM, "CJ Woodman" wrote:
> I recently discovered stained glass window making. After installing my f=
irst
> big
> window, I want to "up the ante." So, I want to take my crystal glaze rec=
ipes
> and make them into sheet glass. Any ideas?
A crystalline glaze need not be too thick to form crystals, but you will
have to find a way to contain the molten glaze and have it separate from
what it was fired on.
Bill
--
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
SUBSCRIBE Clayart CJ Woodman on thu 5 aug 10
See?? See?? Potters are FANTASTIC. What an excellent set of ideas.
Glazing glass instead of a stoneware body is very interesting to me. I can
use polarizing filters (I steal the used 3D glasses from movie theaters) to
check if there are stress lines along the glass edge after annealing,
that would let me know the compatibility of a glaze with the base glass,
followed by heating and cooling cycles to see when stress is induced betwee=
n
the layers. When fusing glass in test batches, stress lines show up as set=
s
of tiny stripes through polarizing filters before crazing or flaking is
observed.
Good points about clarity and opacity, I'd have to work very thin to
avoid pin-holing and bubbles. I wonder if it's possible to make a big craze=
d
hunk of immature but vitrified glaze that's bubble free, then frit it and
bring the frit up to temperature to increase clarity, like using frit to
make small molded glass objects. Pulling a molten ball of glaze into a shee=
t
over molten metal would be beyond my ability in a pottery situation.
Hopefully a thin, sprayed glaze application will work. Floating the base
glass on molten solder might result in a very smooth finished piece, what
perfect suggestion.
Heavy addition of boron or other fluxes will probably retard most large
crystal formations, so I'll need to find weird glass that matches the
existing expansion coefficients of the glaze, rather than formulating glaze
to match glass.
Anyway, until I do appropriate research, this is all conjecture. Thank you=
,
I have a much broader starting point then my original, limited perspective.
I will follow the suggested leads. (I've been reading through
the Crystalline Glaze Forum so far) and will hunt down some folks at Alfred=
.
ivor and olive lewis on thu 5 aug 10
Dear CJ Woodman,
I have a feeling that Stainless Steel will oxidise when heated to
temperatures that are required to mature a Zinc Crystalline glaze.
Some years ago a synthetic gemstone was available from Italy. I saw the
stuff and it seemed to me to be a zinc crystal glass that could be cut int=
o
cat's eye gems.
Could be a new invention.
Best regards,
Ivor Lewis,
REDHILL,
South Australia
James Freeman on thu 5 aug 10
On Wed, Aug 4, 2010 at 10:03 PM, Robert Harris wr=
=3D
ote:
>
> You may be able to find a metal or something similar to "float" it on,
> but I don't have any suggestions on that point
Perhaps a very high temperature glass would work as the substrate (and
left in place). Fused quartz glass, for example, can take cone 6
temperatures for a short time, and can handle the crystal growing
range for quite some time. The problem would be COE matching between
the glass and the glaze. When I took a fused glass class, this
matching was stressed.
Another idea might be to use a true translucent porcelain as the
substrate, which can go to cone 10. Bone china might work too, as I
believe it can take cone 6, or at least close to it. (Also left in
place)
Just tossing out a few ideas. Robert's molten lead idea seems the
most workable, assuming the entire idea is even workable (about which
I make no comment).
All the best.
...James
James Freeman
"All I say is by way of discourse, and nothing by way of advice.=3DA0 I
should not speak so boldly if it were my due to be believed."
-Michel de Montaigne
http://www.jamesfreemanstudio.com
http://www.flickr.com/photos/jamesfreemanstudio/
http://www.jamesfreemanstudio.com/resources
Jaime Salles on thu 5 aug 10
Just a thought, for some fast easy experimenting instead of looking at th=
=3D
e=3D20
problem as making a crystalline glass why don't you try and see if a low=
=3D
fire=3D20
crystalline glaze will adhere to a glass sheet. See if there are any low=
=3D
fire=3D20
crystalline glazes from amaco/ Duncon that can work in the glass slumping=
=3D
=3D20
range Try coat the glass.=3D20
Expect some extremely runny glaze and protect the shelfs and kiln accordi=
=3D
ngly
Jaime Salles=3D20=3D20
www.jsalles.com
marci and rex on thu 5 aug 10
At 09:47 AM 8/5/2010, Jaime Salles wrote:
>Just a thought, for some fast easy experimenting instead of looking at the
>problem as making a crystalline glass why don't you try and see
>if a low fire
>crystalline glaze will adhere to a glass sheet. See if there are
>any low fire
>crystalline glazes from amaco/ Duncon that can work in the glass slumping
>range Try coat the glass.
Glass slumping range is about cone 015 ( approximately 1480 F /
800 C ).......overglaze range... I dont think there are any
commercial glazes that fire below the 06-03 range ,are there ?
and, going on the suggestion that someone made about using a
translucent porcelain as a base, I use Laguna Frost ( the cone 6
version ) .. I work very thin and the pieces are translucent at cone 6....
A thought just occurred to me: I wonder if its possible to use
something like one of the glass shelf papers as a base.. but
it might not release at a crystalline glaze temp..
Marci the chinapainter
David Finkelnburg on thu 5 aug 10
CJ,
You might try contacting the science library at Alfred University. The
glass science collection there is first rate.
There are several challenges in making glass. First, you have to get at
least most of the bubbles out of it so it will be glass and not just cloudy=
,
opaque. Next you have to actually form the glass into a sheet. Finally,
you have to relieve any stresses from forming the glass. Stress relief is
achieved by annealing of the formed sheet--holding at a high enough
temperature to let the stresses relax.
So, you should experiment with making some glass by mixing the
ingredients together DRY and melting them in a crucible of refractory
material. If you heat it well above the melting point that will help to
clear it of bubbles. A mullite crucible will work very well if you're usin=
g
a boron glass. You can recover the glass from the crucible by pouring it
VERY CAREFULLY from the crucible. This means removing the crucible from a
very hot kiln so you should use dark safety glasses to protect your eyes
from IR exposure, clothing to protect yourself from any spills (leather
shoes are good!), a face shield to prevent spatter, long sleeves like
welders use, well insulated gloves like for Raku. Do please be careful.
Practice with a cold crucible to get used to the weight and how you will
manage it.
I have only done this with small amounts of glass--enough to cast glass
in molds the size of the palm of one's hand. If the casting isn't put back
in an annealing furnace for stress relieving the glass will eventually
crack--usually within a few weeks.
Good glass making!
Dave Finkelnburg
http://www.mattanddavesclays.com
-----------------------------
Date: Wed, 4 Aug 2010 20:31:17 -0400
From: CJ Woodman
Subject: Crystalline glaze: In sheets?
I recently discovered stained glass window making. After installing my f=
=3D
irst big=3D20
window, I want to "up the ante." So, I want to take my crystal glaze rec=
=3D
ipes=3D20
and make them into sheet glass. Any ideas?
As a potter, I make glass all the time... but only as supremely thin coat=
=3D
ings on=3D20
stoneware. None of the stained glass people make their own glass "from=3D2=
0=3D
batch," even when they have kilns! So I turn to the potters on this one.=
=3D
Louis Katz on fri 6 aug 10
My gut feeling is, "It'll never work, you should try it".
My first problem is that crystalline substances have different coefficien=
=3D
ts
of expansion than glasses, not even considering phase changes. Little cra=
=3D
cks
turn into big cracks given any significant stress at all, so if you have =
=3D
a
bunch ( or even one) of small cracks they will grow. Given that however I=
=3D
have a piece of glass given to me 20 years ago because of a small stress
crack caused by a bit of glass with a different coefficient of expansion.=
=3D
The crack has grown from about 1/2 inch to about 2 inches.
Also my slipcast glass is cracked but its porous structure allows the cra=
=3D
cks
to terminate in round cavities. This helps prevent the crack from continu=
=3D
ing
to grow.
It occurs to me that bottle glass is already much like a crystalline glaz=
=3D
e
in that it is low in alumina.=3D20
I would start by trying to "float" it on a graphite coated mold. The sili=
=3D
ca
glass idea has me intrigued as well and I would try that with a graphite =
=3D
coat.
It would probably be smart to frit your glass mixture first so that you g=
=3D
et
good ingredient distribution.
Good luck!
http://falcon.tamucc.edu/~lkatz/LK/slipcastglass/index.htm
Robert Harris on fri 6 aug 10
Hi CJ,
I think the biggest problem of doing glaze over glass is that
commercial soda glass has a much much lower melting point than the top
temperature of most glazes (well, melting point is a misnomer since
glass is a supercooled liquid at room temperature, but you get my
point). In your first post you mention that you have your own crystal
glaze recipes. You will need to to match the melting point of any
glass you use as a substrate to the top temperature to which you fire.
I know that there are all sorts of glasses out there so you may be
able to find one. When I was a chemistry undergrad we used to use what
were supposedly pure quartz flasks tubes for heating anything over
700C or so. I just went to a couple of art glass sites, and the peak
temperature table for most of their glasses seemed to be 1500F - or
cone 013. You will need to do some serious research to find the
appropriate glass to use at Cone 6 (about 2200F)), let alone cone 10
(2350F).
When I was suggesting using lead, I was imagining that you'd just dump
in the dry ingredients over a bunch of solid lead/solder, then do your
normal firing and see what happened. Perhaps you got that. (You
mentioned doing molten glass over molten metal so I wasn't sure).
Robert
On Thu, Aug 5, 2010 at 11:19 PM, SUBSCRIBE Clayart CJ Woodman
wrote:
> See?? See?? Potters are FANTASTIC. What an excellent set of ideas.
>
> Glazing glass instead of a stoneware body is very interesting to me. =3DA=
0I=3D
can
> use polarizing filters (I steal the used 3D glasses from movie theaters) =
=3D
to
> check if there are stress lines along the glass edge after annealing,
> that would let me know the compatibility of a glaze with the base glass,
> followed by heating and cooling cycles to see when stress is induced betw=
=3D
een
> the layers. =3DA0When fusing glass in test batches, stress lines show up =
as=3D
sets
> of tiny stripes through polarizing filters before crazing or flaking is
> observed.
>
> Good points about clarity and opacity, I'd have to work very thin to
> avoid pin-holing and bubbles. I wonder if it's possible to make a big cra=
=3D
zed
> hunk of immature but vitrified glaze that's bubble free, then frit it and
> bring the frit up to temperature to increase clarity, like using frit to
> make small molded glass objects. Pulling a molten ball of glaze into a sh=
=3D
eet
> over molten metal would be beyond my ability in a pottery situation.
> =3DA0Hopefully a thin, sprayed glaze application will work. =3DA0Floating=
the=3D
base
> glass on molten solder might result in a very smooth finished piece, what
> perfect suggestion.
>
> Heavy addition of boron or other fluxes will probably retard most large
> crystal formations, so I'll need to find weird glass that matches the
> existing expansion coefficients of the glaze, rather than formulating gla=
=3D
ze
> to match glass.
>
> Anyway, until I do appropriate research, this is all conjecture. =3DA0Tha=
nk=3D
you,
> I have a much broader starting point then my original, limited perspectiv=
=3D
e.
> =3DA0I will follow the suggested leads. =3DA0(I've been reading through
> the Crystalline Glaze Forum so far) and will hunt down some folks at Alfr=
=3D
ed.
>
--=3D20
----------------------------------------------------------
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