2ley on mon 14 nov 05
From: "Debbie White"
> Does anyone have experience firing these for decoration in the bottom of a
> pottery bowl.
I'm not sure how they'd fare at cone 6. They melt at a very low
temperature, compared to glazes. Two fellow students worked with them,
firing to ^04, and the results were beautiful. Just remember to put some
Borax in to help them flux properly. Not a lot, but enough to cover the
spot they sit on.
Good luck,
Philip Tuley
Debbie White on mon 14 nov 05
Hello,
I recently purchased some decorative glass balls from a crafts store. Ones
that intended use was for putting in a bowl or clear vase to hold a flower
arrangement or just to look pretty. These are more like disk shapes, than
balls, and may have colour in them.....blues, yellow etc. Some have shiny
silver or may be a solid colour.
Does anyone have experience firing these for decoration in the bottom of a
pottery bowl.
Do they melt well at cone 6?
Is there problems with them?....will they explode in the kiln?
Will the colours burn out?
Does the shiny silver ones have something in them that might be hazardous to
breath if fired?
Will they craze dangerously?
I also have some shards of stained glass given to me. I read you should
crush it first before use. Is that really necessary if it will melt anyhow.
What is the optimum thickness of glass to put in the bottom of a pot....can
it be too thick or thin?
Appreciate your advice!
Debbie White
Arnold Howard on tue 15 nov 05
Debbie, the main problem is coefficient of expansion between the glass and
the clay. If the coefficient is off, the glass will crack. (In other words,
if the glass and clay heat and cool at different rates, the glass will
crack.) Mixing different types of glass will also complicate the coefficient
problem.
The glass will not explode inside the kiln. It will become liquid at cone 6
and melt into a puddle. The colors will probably shift, but they shouldn't
burn out. I would vent the kiln during firing no matter what type of glass
you use.
The thicker the glass, the slower it must cool. Otherwise the stresses
formed during cooling will crack the glass. I have a friend who fired glass
frit (small glass particles) into molds of about 3" thick. The glass took
three days to cool safely.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
From: "Debbie White"
> I recently purchased some decorative glass balls from a crafts store.
> Ones
> that intended use was for putting in a bowl or clear vase to hold a flower
> arrangement or just to look pretty. These are more like disk shapes, than
> balls, and may have colour in them.....blues, yellow etc. Some have shiny
> silver or may be a solid colour.
>
> Does anyone have experience firing these for decoration in the bottom of a
> pottery bowl.
>
> Do they melt well at cone 6?
> Is there problems with them?....will they explode in the kiln?
> Will the colours burn out?
> Does the shiny silver ones have something in them that might be hazardous
> to
> breath if fired?
> Will they craze dangerously?
>
> I also have some shards of stained glass given to me. I read you should
> crush it first before use. Is that really necessary if it will melt
> anyhow.
> What is the optimum thickness of glass to put in the bottom of a
> pot....can
> it be too thick or thin?
steve graber on tue 15 nov 05
a few years back ceramics monthly had an article on a guy who did spectacular work with glass. he did platter work mostly i recall. his recipes were based on molson, rolling rock, coors, etc color bottles. a nice way to write off your beverage habit as a business expense?
while glass melts at low temp, as long as the pot has a place to hold the melted glass & the glass isn't too thick, it'll work. ~ turn into something.
this guy got results that looked like sunrise & sunset coloration's.
i've messed around with glass & have had cases where i went too thick on glass (maybe 1/2 inch) & upon cooling the expansion difference of the glass to the pot broke the pot. some pots cracked & let glass out onto the kiln shelf.
meanwhile, the extra subsurface cracking you get on a contained glass melt would - in sunlight - look like a bed of gem stones!
~ i wish beer came in more colors then just clear, brown, or green bottles...
see ya
steve
Arnold Howard wrote: Debbie, the main problem is coefficient of expansion between the glass and
the clay. If the coefficient is off, the glass will crack. (In other words,
if the glass and clay heat and cool at different rates, the glass will
crack.) Mixing different types of glass will also complicate the coefficient
problem.
The glass will not explode inside the kiln. It will become liquid at cone 6
and melt into a puddle. The colors will probably shift, but they shouldn't
burn out. I would vent the kiln during firing no matter what type of glass
you use.
The thicker the glass, the slower it must cool. Otherwise the stresses
formed during cooling will crack the glass. I have a friend who fired glass
frit (small glass particles) into molds of about 3" thick. The glass took
three days to cool safely.
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
From: "Debbie White"
> I recently purchased some decorative glass balls from a crafts store.
> Ones
> that intended use was for putting in a bowl or clear vase to hold a flower
> arrangement or just to look pretty. These are more like disk shapes, than
> balls, and may have colour in them.....blues, yellow etc. Some have shiny
> silver or may be a solid colour.
>
> Does anyone have experience firing these for decoration in the bottom of a
> pottery bowl.
>
> Do they melt well at cone 6?
> Is there problems with them?....will they explode in the kiln?
> Will the colours burn out?
> Does the shiny silver ones have something in them that might be hazardous
> to
> breath if fired?
> Will they craze dangerously?
>
> I also have some shards of stained glass given to me. I read you should
> crush it first before use. Is that really necessary if it will melt
> anyhow.
> What is the optimum thickness of glass to put in the bottom of a
> pot....can
> it be too thick or thin?
______________________________________________________________________________
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.
---------------------------------
Yahoo! FareChase - Search multiple travel sites in one click.
Debbie White on wed 16 nov 05
Thanx for all the great advice re melting glass.
Got some very interesting effects....especially the red glass balls. The
ones which where sold red melted to a very rich red....a lot of ohhh and
auwsh!! when people see it.
Some, however, did craze....the thicker ones. I will have to try the slow
cool method. Others actual bubbled and left craters. I'm not sure if that
meant it overfired or underfired....it was in the cooler part of the
kiln....did not reach cone 6.
Will keep experimenting.
Happy Potting!
Debbie White
Pontypool, Ontario
| |
|
