Peta Clark on mon 25 nov 96
It looks like normal clay is best for what I want to do. Speaking of things
that melt have you done anything with glass? Can you add it with the first
firing or do you have to add it later?
Cookee Klein on tue 26 nov 96
I have melted glass in a few pieces at both the bisque and glazing
stages. The best glass to use is lead free because the lead tends to
collect in one spot and turn a very nasty yucky black color. I often
use pieces of colored bottles, usually at the glazing stage because of
the increased heat. It has turned out wonderful on some pieces and
hideous on others. You should just test and see what happens!
Christine Davis on wed 27 nov 96
I have fired glass marbles in earthenware at cone 022 and have had limited
success.
Don Goodrich on wed 27 nov 96
Peta,
What kind of glass, and what are you doing with it? If you're using
broken, crushed or powdered glass from sources such as bottles or stained
glass, by all means add it only for your high firing, because at low bisque
temperatures it won't melt: you'll have to remove it to do your glazing, then
apply it all over again. Also, be aware that it's really runny! It's safest
to use it on areas that will be horizontal and confined during firing. Some
potters have put shards of colored glass bottles through the handles of jugs
before firing. These would then melt and run down the sides. If you do this,
be prepared to grind excess glass off the bottoms of your pots and off the
kiln shelves.
It's difficult to get a good match of fit between glass and clay. This
means that when cooled, the glass will probably have a very crackled
appearance,and may be used to good effect giving sparkle and depth to a
surface. However, it's not advisable to use such surfaces for serving food.
Hopefully some others with clay/glass experience will surface for this.
Marcie, are you there?
Don Goodrich in way too cold Zion, Illinois
mudlady@ATT.NET on fri 3 aug 01
Does anyone out there know the technique for melting
glass on the surface of fired clay. I fire to ^10 in
redux and want to make sushi plates with glass melted
over the surface. I had a disaster in the last firing.
The rectangular plate had glass over the surface and
when I opened the kiln the corners had broken off. Is
that from the pressure of the melted glass? Help
mudlady@worldnet.att.net Thanks Collette
james w. thomas on fri 3 aug 01
There are many factors that affect glass firing. I've not had the opportunity to fire glass onto clay yet but cone 10 is probably too hot for the glass. You might try a test fire using a piece that has been cone 10 fired and after it cools refire with the glass layed in like you want.Glass has a COE (Coefficient of expansion and contraction). Most glass will melt (reaches a liquified state) between 1550 F. to 1620 F. so cone 10 was probably over kill for the glass. Check out Glass Fusing Book One, and Two by Boyce Lundstrum for technical info on glass. These are inspiring books and will give lots of ideas for projects.
It sounds like the glass could have been thermal shocked by either heating too fast or cooling too fast. If the shards of glass have sharp edges it probably cracked on the way down. If the shards have melted edges at the break line it was probably heated up too fast.
An anneal cycle should have been programmed into the firing at about 960 F. Circa 980 F. is considered the strain point of glass. When a piece of glass is fired the edges heat and cool quicker than the center. In cool down the glass has to have a soak period at about + or - 960 F. or so to release the strain. This is called the anneal temp.
There are so many factors I would have to see the piece to tell more about what happened.It would take a couple of chapters to give you all the information please consult the above mentioned sources. If I can be of further assisstance please contact me off line.
>Reply-To: Ceramic Arts Discussion List
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: glass
>Date: Fri, 3 Aug 2001 12:38:24 +0000
>
>Does anyone out there know the technique for melting
>glass on the surface of fired clay. I fire to ^10 in
>redux and want to make sushi plates with glass melted
>over the surface. I had a disaster in the last firing.
>The rectangular plate had glass over the surface and
>when I opened the kiln the corners had broken off. Is
>that from the pressure of the melted glass? Help
>mudlady@worldnet.att.net Thanks Collette
>
>______________________________________________________________________________
>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.
Get your FREE download of MSN Explorer at http://explorer.msn.com
Steve Mills on sat 4 aug 01
We used to melt glass on/into pots, though not as high as ^10, we found
the best technique was to place the glass onto an already glazed
surface, this helped the glass to bond to the surface it was on, and if
the glaze used was a white opaque it helped to show up the colour of the
glass.
Steve
Bath
UK
In message , mudlady@ATT.NET writes
>Does anyone out there know the technique for melting
>glass on the surface of fired clay. I fire to ^10 in
>redux and want to make sushi plates with glass melted
>over the surface. I had a disaster in the last firing.
>The rectangular plate had glass over the surface and
>when I opened the kiln the corners had broken off. Is
>that from the pressure of the melted glass? Help
>mudlady@worldnet.att.net Thanks Collette
--
Steve Mills
Bath
UK
Harry on sat 4 aug 01
Hi Collette,
The following link gives all kinds of "how to" info.
Harry in Iowa
http://www.warmglass.com/
----- Original Message -----
From:
To:
Sent: Friday, August 03, 2001 7:38 AM
Subject: Re: glass
> Does anyone out there know the technique for melting
> glass on the surface of fired clay. I fire to ^10 in
> redux and want to make sushi plates with glass melted
> over the surface. I had a disaster in the last firing.
> The rectangular plate had glass over the surface and
> when I opened the kiln the corners had broken off. Is
> that from the pressure of the melted glass? Help
> mudlady@worldnet.att.net Thanks Collette
>
>
____________________________________________________________________________
__
> 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.
>
>
Fay & Ralph Loewenthal on sun 5 aug 01
Collette, what are you trying to achieve with the glass?
One has to remember that we go through all the=20
calculations, and tests to find a glaze with the same COE=20
as the clay we are using. If you use any normal or art glass=20
in clay, either the glass will shatter or the clay will break=20
(as in your case), or both. Glass also needs to anneal. This=20
is achieved by taking the glass up to about 800 C then=20
dropping the temperature fast to 500 C by opening the
kiln door / lid. Often the clay cannot take the temperature
shock and will crack or shatter etc. I use a fairly heavily
grogged clay, or a Raku clay, to make clay moulds for my
glass slumping.=20
Hope this helps.
Kind regards from Ralph in Cape Town.
David Hewitt on sun 5 aug 01
I used to do this kind of thing using different coloured wine bottle
glass placed over a glaze in the bottom of relatively small items - 3 to
5 inches in diameter. They were fired in oxidation to cone 8.
Occasionally one of the larger ones would crack in the glaze firing.
I am sure that the reason was that the glass had a very different
coefficient of expansion from the body and so in the extreme it was
enough to crack the pot.
This is more likely to happen the thinner the section of the pot in
which the glass is placed
David
In message , mudlady@ATT.NET writes
>Does anyone out there know the technique for melting
>glass on the surface of fired clay. I fire to ^10 in
>redux and want to make sushi plates with glass melted
>over the surface. I had a disaster in the last firing.
>The rectangular plate had glass over the surface and
>when I opened the kiln the corners had broken off. Is
>that from the pressure of the melted glass? Help
>mudlady@worldnet.att.net Thanks Collette
--
David Hewitt
David Hewitt Pottery ,
7 Fairfield Road, Caerleon, Newport,
South Wales, NP18 3DQ, UK. Tel:- +44 (0) 1633 420647
FAX:- +44 (0) 870 1617274
Web site http://www.dhpot.demon.co.uk
mel jacobson on tue 8 jul 03
the reason potters do not like glass talk
is that:
if you mess around, stand around, be a part of
a glass studio, then you want go home
and build a glass studio, get those pipes
and those wooden former things....and,
of course, a bucket of water.
i don't want to talk about glass, hot glass,
pipes, wooden things, cuzz i really like them.
so. no more talk of glass. i am too busy and
don't have the time to build a glass kiln...and,
they are on all the time...glowing in your studio,
making you feel guilty that you are not blowing glass.
and, of course, then you have to make one of those
cool down kilns...and that would not be fun...or, would
it?
so, no more glass talk.
mel
soon we will have to talk about cement...it is a ceramic
product you know...as is glass.
calcined limestone.
we will have to design a wheel that we can
throw cement on.
From:
Minnetonka, Minnesota, U.S.A.
web site: my.pclink.com/~melpots
or try: http://www.pclink.com/melpots
new/ http://www.TICK-ATTACK.COM
| |
|
