Mike Gordon on sun 24 nov 02
Hey people,
How much electricity does it take/cost to run a ball mill 20 hrs? I
thought this was supposed to be free! Mike Gordon
David Hendley on sun 24 nov 02
I'm the one who mentioned a few months ago that I regularly use blue
glass to use as a slip-glaze ingredient and as a source of free cobalt.
Blue bottles are not common, but not rare.
I even recovered a blue bottle at the Appalachian Center for Crafts last
summer.
The most common ones are from Arizona Iced Tea (Memory Formula),
various wines, Skyy vodka, and the Skyy vodka "malt beverage"
that is heavily advertised these days.
This drink, by the way, is, truth be told, marketed at teenagers. I
tried one, since I like the blue bottle, and it tastes like Sprite. You
could drink 3 or 4 in no time and not know you've had the equivalent
of 3 shots of liquor.
I estimate that blue bottle glass is about 1% pure cobalt (cobalt oxide
is 70-71% pure cobalt), so you are not getting that much free cobalt,
but enough to color a glaze.
I use a slip glaze that is 60% blue glass cullet and 40% ball clay, plus
2% soda ash. It is a nice deep, but not dark, blue.
The biggest value of using glass cullet is that you have a source of
non-soluble sodium, plus a little of some other fluxes, and some
silica, with no added alumina. This allow you to add a high amount of
clay to a slip recipe and still not make it over-supplied with alumina.
Plus it's free.
To process bottles, I put 5 in the firebox of my wood kiln when I
first start the fire. In a couple of hours, the bottles are slumped and
red-hot. I then remove them with an iron rod and drop them into
a bucket of water, which shatters them into a "coarse sand" size.
About 20 hours in my ball mill makes a 200 mesh powder.
I ball mill dry and use squared off porcelain grinding medium, rather
then round balls.
I have a friend who likes the Arizona tea. Between him and myself,
I have found and processed enough blue bottles to have a 5 gallon
bucket full to the brim with blue glass cullet. BTW, it's nearly white
by the time it is ball mulled to a fine powder.
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com
David Hendley on tue 26 nov 02
----- Original Message -----
> Hey people,
> How much electricity does it take/cost to run a ball mill 20 hrs? I
> thought this was supposed to be free! Mike Gordon
In my case, 66 cents:
3 amps X 110 volts X 20 hours X 10 cents/kilowatt hour
This will yield about 4 pounds of frit. I only run my ball mill at night;
it's too noisy to have on while you are in the building!
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com
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