McCoy, Jack Eugene on tue 24 nov 98
How well does sand (60 to 80 mesh) work as grog in a clay body?
Tom Wirt on wed 25 nov 98
-----Original Message-----
Subject: Using sand as grog
----------------------------Original message----------------------------
>>How well does sand (60 to 80 mesh) work as grog in a clay body?
Jack
One experience I have had is that the sand, after firing will tend to stand a
little proud of the clay body. Talking to Steve at Aardvark Clay, he says it's
because the clay body shrinks away from the sand particles. Just means a bit
more grinding.
Another point in using sand....try to find a rounded grain...water washed or
wind blown. Makes for a much smoother throwing experience. Silica used for
sandblasting is sharp edged.
Tom
Fay & Ralph Loewenthal on thu 26 nov 98
Jack McCoy asked >How well does sand (60 to 80 mesh) work as grog
in a clay body?
Jack sand is mostly silica. That is where glass comes from.
Grog is fired crushed and sifted clay. I would be very
careful about using sand as grog. I tried using some beach
sand on my kiln shelves, and I am still cleaning it off. The
damn stuff melted. Hope this helps Ralph in PE SA
John K. Dellow on fri 27 nov 98
I would not use sand in terracotta bodies as an opener for fatty clays. It
makes for stiff bodies which will abrasive, hard on the hands. The sand will
take in a lot of water while throwing and will cause pots to slump . Better
to use a grog or crushed rock. My body has a trachyte rock of 40 mesh.
John Dellow the flower pot man
http://welcome.to/jkdellow
MRS SANDRA L BURKE on sat 28 nov 98
I was glad to see your post about the sand on kiln shelves---Someone
once told me it would be a good way to clean up the glaxe that had
fused to the shelves, something about putting sand on the shelves and
firing the kiln. I can't remember the exact instructions. i was about
to call my friend and ask for the details again. Good thing I didn't
Sandy B
Charlies and Linda on sat 28 nov 98
Sand is not always silica especially at the beach.
Ralph noted that he is still cleaning off shelves that had beach sand
spinkled on them.
Beach sand may be composed of volcanic glass (black beaches for example)
or crushed sea shells or several other rock compositions that may not be
high in silica. Few of these other minerals will match the refractory
nature of pure silica.
We are lucky to live on the very edge of the "Sandhills" of North
Carolina near Seagrove. Clay can be dug from the road bank in front of
the studio and thrown will little additional amendments. Sand washes
down the road from my neighbors property and is deposited in the same
ditch only 25' from the clay. After a test fire it was determined that
it is of the silica variety and is now used in several fashions around
the studio.
Test, test, test.
Ralph-I have scraped many shelves for other reasons. Example-I
substituted gerstley borate for EPK in kiln wash years back. I was in a
hurry and trying to remember the other ingredient besides silica. I now
try to write down even the simplest things....
Charlie Riggs
http://www.cclay.com/criggs/index.htm
Cheryl L Litman on sun 29 nov 98
I use sandbox sand (from Home Depot) sprinkled on the shelves under slabs
fired to cone 6 and have had no problems with it fusing.
Cheryl Litman
Somerset, NJ
email: cheryllitman@juno.com
On Sat, 28 Nov 1998 10:25:48 EST MRS SANDRA L BURKE
writes:
>----------------------------Original
>message----------------------------
>I was glad to see your post about the sand on kiln shelves---Someone
>once told me it would be a good way to clean up the glaxe that had
>fused to the shelves, something about putting sand on the shelves and
>firing the kiln. I can't remember the exact instructions. i was about
>to call my friend and ask for the details again. Good thing I didn't
>Sandy B
>
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Richard Gralnik on tue 1 dec 98
I seem to remember a posting here once about this subject, and one
warning against using sand as grog had to do with the shape of the
particles. Apparently grains of sand tend to be shaped like little
ball bearings while grog has a rougher surface. This difference had
an effect on the behavior of the clay when fired.
Sorry I don't remember the details.
Richard
At 10:32 AM 11/26/98 EST, you wrote:
>----------------------------Original message----------------------------
>Jack McCoy asked >How well does sand (60 to 80 mesh) work as grog
>in a clay body?
>Jack sand is mostly silica. That is where glass comes from.
>Grog is fired crushed and sifted clay. I would be very
>careful about using sand as grog. I tried using some beach
>sand on my kiln shelves, and I am still cleaning it off. The
>damn stuff melted. Hope this helps Ralph in PE SA
>
>
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