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embedded glass

updated sat 10 feb 07

 

Tom Buck on thu 8 feb 07


Ivy:
no, you are ok on thinking bottle glass would give you a
variegated surface on a pot. but be aware that conventional container
glass is 75%w silica sand, 20% soda ash, 5% limestome (aka whiting), and
small amounts of other materials according to end-use. when old bottles
are pulverized the powder is called "cullet".

your analysis differs from standard bottle glass, but not enough
to cause a problem if you are firing appropriately.

when container glass is made from silica/soda/lime, it melts at
2000 oF (1093 oC) or Orton Cone 01, so one can expect your glass pieces to
do the same. Because soda/lime glass lacks alumina, it will melt and be
runny at cones above the common low-fire range, C08 to C03, of raku and
earthenware processes.

If you wish to embed small glass pieces on the surface of your
pots, and hence need glass that does not run at mid-fire cones, C4-C7,
then please seek out specialty glasses that will handle the greater
heatwork of higher temperatures.

good pots. peace Tom B.

Tom Buck ) -- primary address.
"alias" or secondary address.
tel: 905-389-2339 (westend Lake Ontario, province of Ontario, Canada).
mailing address: 373 East 43rd Street, Hamilton ON L8T 3E1 Canada

Joyce Lee on thu 8 feb 07



Speaking of embedded glass, does anyone use "art glass" embedded in
clay? If so, how high are you able to fire and have the glass retain color?
I have a lot of the "art glass" by happenstance and accident. I would like
to use it on pots, but the colors look pretty fragile to me.

Thank you for taking the time to read this and perhaps to respond.

Joyce
In the Mojave desert where I have now changed servers, browsers, email
programs and anti-virus programs. So far; so good. Please note my
change of address. Funny part is that three years ago I was with this
same server who kept several hundred of my e-mails in a file under my
name. SO when I re-registered with them, they sent me the 3 year old
messages. The posts had their old dates on them but they also carried
that day's date.... Feb. 4, 2007. I had responded to a dozen or so before
noticing that we were talking about Christmas and other events that were
well past. If I was befuddled, you should have read the posts from my
recipients who asked questions like: "What party?'" or "Don't come
this Thursday. We haven't held bookclub in two years!" "What Time
Warp are you IN?"

Lee Love on fri 9 feb 07


I have used old cobalt and cranberry glass.

--
Lee in Mashiko, Japan
Minneapolis, Minnesota USA
http://potters.blogspot.com/

"To affect the quality of the day, that is the highest of arts." -
Henry David Thoreau

"Let the beauty we love be what we do." - Rumi

iglasgo on fri 9 feb 07


Thanks for the great info! Getting some idea of the melting temp helps
me get my head around this concept... I think I will try the glass
bits in a Cone 04 glaze and see what happens.
-Ivy G.

--- In clayart@yahoogroups.com, Tom Buck wrote:
>
> Ivy:
> no, you are ok on thinking bottle glass would give you a
> variegated surface on a pot. but be aware that conventional container
> glass is 75%w silica sand, 20% soda ash, 5% limestome (aka whiting), and
> small amounts of other materials according to end-use. when old bottles
> are pulverized the powder is called "cullet".
>
> your analysis differs from standard bottle glass, but not enough
> to cause a problem if you are firing appropriately.



> when container glass is made from silica/soda/lime, it melts at
> 2000 oF (1093 oC) or Orton Cone 01, so one can expect your glass
pieces to
> do the same. Because soda/lime glass lacks alumina, it will melt and be
> runny at cones above the common low-fire range, C08 to C03, of raku and
> earthenware processes.



>
> If you wish to embed small glass pieces on the surface of your
> pots, and hence need glass that does not run at mid-fire cones, C4-C7,
> then please seek out specialty glasses that will handle the greater
> heatwork of higher temperatures.
>
> good pots. peace Tom B.
>
>

The Goodsons on fri 9 feb 07


Joyce,
I haven't tried art glass, but I did embed some beach glass in the
bottom of a plate. We went on a great vacation to Vancouver Island, and
picked up some beautiful beach glass. I thought it would be great to
embed it in the bottom of a plate. I pushed it into the plate while it
was still damp, close to leather hard. It bisque fired okay. I then
glazed it with a clear glaze and I fired it to cone 6. The plate
cracked around the larger embedded pieces (not good). I guess that I
will just have to go back to Vancouver Island to get some more :-) . The
color did remain from the green and brown glasses. Since then I have
only placed the glass on top of the glaze and then fired.

Good luck,
Linda Goodson
Lincolnton, NC

p.s. the smaller pieces were mostly 1/4 inch in diameter- they did
fine. the larger pieces were about 1/2 inch or more in diameter.