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I am Looking for a cheap source of glass
Posted: Thu Dec 04, 2003 12:38 pm
by hoknok
I am wanting to find an inexpensive source for castable glass. Yes, I know, who isn't.. but I thought I would ask.
I am looking for glass with a coe of 90 in chunks, bricks etc. I will be using the glass for casting purposes. I have been to various suppliers websites but wanted to get other peoples opinion on which supplier they use for great prices.
Also, any ideas on where people get float glass cheap. For me, I am working with a glass suplier who sells me glass that has been sitting arround for a long time or damaged. Just wanted to know how others are getting it?
I am using the float glass to learn from. I also did more tests on various glass bottles that were broken into chunks (coke, beer-brown, mellowyellow green) with the results and detailed firing schedules if anyone is interested.
Thanks
Mike Hawkins (hoknok)
Posted: Fri Dec 05, 2003 4:02 am
by Lauri Levanto
I do almost only castings.
I like the glass clear, and use the pilt (scrap) glass
from a nearby glass factory. It is cheap, has a
COE xx, but if it is from one melt, it is self compatible.
I crush and wash it, buy colored frits from the
same manufacturer as that glass factory.
Works fine for me.
-lauri
Posted: Fri Dec 05, 2003 4:13 am
by hoknok
Do you add the colored frit to your clear glass to color the batch?
The art glass is so expensive, esepcially if I want to do large castings.
Posted: Fri Dec 05, 2003 11:18 am
by Bert Weiss
Hok
If you get lucky, maybe the factory cullett melts with good properties. Most likely it is stiff and requires a high temp to get it to flow.
What you pay for when using BE or Uroboros or Spectrum is the research and formulation that allows you to get a good flow at relatively low temps. Pay more / cast once. The big boys use 40% lead glass from Schott. BIG BUCKS there, plenty of sparkle though.
I once had an inexpensive source for 20% lead crystal, but they moved production offshore.
You could get lucky, but if there was an easy cheap solution, we'd likely have heard about it. Talk to OJ Gabbert and see if they are offering a glass that will work for what you want. Gabbert has a business "cleaning up" at glass factories. They sell the scrap and cullett to glass blowers for remelting.
Posted: Fri Dec 05, 2003 6:23 pm
by watershed
Gabbert GB-12 works OK. Coe unknown. 25% lead. last check, $0.20 a lb. PLus shipping from WV.
Spectrum IS COE 96, and casts well, though it may be hard to get cullett in small (under a ton ) amounts. It does take 1500+ to get it really running, but good results, if your mold will handle it.
Greg
Posted: Sun Dec 07, 2003 3:25 am
by Lauri Levanto
>Do you add the colored frit to your clear glass to color the >batch?
> The art glass is so expensive, esepcially if I >want to do large castings.
It seems that all the Finnish art glass factories use much the
same kind of glass. They all color it with frit from one
source. I buy my frit there.
I mainly use clear, but I have used colored frit in places.
If the frit is fine enough, and when in doubt premixed
with the base clear frit, the eventual stresses
seem not to be a factor.
I have once potmelted with raw chrome oxid
as colorant. Got a wonderful tint.
-lauri
Posted: Sun Dec 07, 2003 10:45 am
by Bert Weiss
lauri wrote:
I have once potmelted with raw chrome oxid
as colorant. Got a wonderful tint.
-lauri
Lauri
I'm surprised to hear that you got good results with Chrome. I once tried smelting float glass with chrome. I got some lovely green glass, but also got killer stones of undissolved chrome.
Posted: Mon Dec 08, 2003 12:35 am
by hoknok
Gabbert GB-12 works OK. Coe unknown. 25% lead. last check, $0.20 a lb. PLus shipping from WV.
Spectrum IS COE 96, and casts well, though it may be hard to get cullett in small (under a ton ) amounts. It does take 1500+ to get it really running, but good results, if your mold will handle it.
Greg
CURRENTLY I AM FIRING SPECTRUM WITH A MIX OF FLOAT GLASS TO TEST COMPATABILITY. I HAVE FLOAT GLASS IN THE BOTTOM OF MY MOLD AND SPECTRUOM AS A TOP LAYER.
I THINK THE FLOAT GLASS IS AROUND 100 COE? DOES A 4 PERCENT CHANGE IN COE MAKE A DIFFERENCE OR IS IT IN LINE WITH "COMPATABILITY"? I AM FIRING THE KILN TO O4 (1846 F) FOR A GLAZE FIRE AND DECIDED TO ADD THE "TEST" GLASS SINCE I HAD SHELF SPACE. IN THE LAST FIRE IT SEEMED THAT I HAD TO TAKE THE THICK FLOAT GLASS TO AT LEAST 1700 BEFORE I SAW ANYTHING SLUMP. AT 1750 THE GLASS BEGAN TO MELT. MY KILN FIRES TO CONE 12 (2384) SO A HIGHER FIRE IS NOT A PROBLEM.
I HAVE A CONE ART KILN WITH 4 SECTIONS THAT GIVE ME 22 CUBIC FEET. I CAN TAKE DOWN A SECTION OR MORE FOR SMALLER FIRES. I USE A ORTON AUTOFIRE PLUS CONTROLLER.
I READ ONE CAN TEST THE COE WITH A POLARIZER... HOW? I THOUGHT IT WAS TO SEE STRESS CRACKS, NOT TEST COE?
Posted: Mon Dec 08, 2003 3:00 am
by Lauri Levanto
Bert:
>Lauri
>
> I'm surprised to hear that you got good >results with Chrome. I once tried smelting float glass with >chrome. I got some lovely green
> glass, but also got killer stones of >undissolved chrome.
It was one of those lucky incidents. I had done some
chrome oxide paste for ceramic patina in a stainless steel pot.
The I used the same pot to crack hot glass into water.
The resulting frit got contaminated, leaving a nice
green tint.
An unrepeatable process.
Another ecperiment was to paint Chrome oxis slurry
on float and fuse another clear float on top.
The result was dark matt green like bad paint.
-lauri
Posted: Mon Dec 08, 2003 7:05 pm
by watershed
I seem to remember that COE is Exponential. IF so, then the difference between 96 and 100 is 40, or 400, I can't remember.
Oh and your float could be anywhere from 80 something to 120 something. Depending on mfg ect...
Greg
Posted: Tue Dec 09, 2003 12:16 am
by Bert Weiss
hoknok wrote:Gabbert GB-12 works OK. Coe unknown. 25% lead. last check, $0.20 a lb. PLus shipping from WV.
Spectrum IS COE 96, and casts well, though it may be hard to get cullett in small (under a ton ) amounts. It does take 1500+ to get it really running, but good results, if your mold will handle it.
Greg
CURRENTLY I AM FIRING SPECTRUM WITH A MIX OF FLOAT GLASS TO TEST COMPATABILITY. I HAVE FLOAT GLASS IN THE BOTTOM OF MY MOLD AND SPECTRUOM AS A TOP LAYER.
I THINK THE FLOAT GLASS IS AROUND 100 COE?
I think it is closer to 86. Unless you get the glass hot enough to actually smelt and become an all new COE it shouldn't work.
DOES A 4 PERCENT CHANGE IN COE MAKE A DIFFERENCE OR IS IT IN LINE WITH "COMPATABILITY"? I AM FIRING THE KILN TO O4 (1846 F) FOR A GLAZE FIRE AND DECIDED TO ADD THE "TEST" GLASS SINCE I HAD SHELF SPACE. IN THE LAST FIRE IT SEEMED THAT I HAD TO TAKE THE THICK FLOAT GLASS TO AT LEAST 1700 BEFORE I SAW ANYTHING SLUMP. AT 1750 THE GLASS BEGAN TO MELT. MY KILN FIRES TO CONE 12 (2384) SO A HIGHER FIRE IS NOT A PROBLEM.
Float glass should slump around 1100ºF so you have some wacky stuff going on relative to temps.
I HAVE A CONE ART KILN WITH 4 SECTIONS THAT GIVE ME 22 CUBIC FEET. I CAN TAKE DOWN A SECTION OR MORE FOR SMALLER FIRES. I USE A ORTON AUTOFIRE PLUS CONTROLLER.
I READ ONE CAN TEST THE COE WITH A POLARIZER... HOW? I THOUGHT IT WAS TO SEE STRESS CRACKS, NOT TEST COE?
The polarizer is a tricky tool to use. It is most accurate when a colored glass is fired to full flat fuse in a clear glass and viewed from the edge. You can also see stress through the flat surface.