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making and testing a clay body?????

updated fri 17 jun 05

 

Peter Coates on wed 15 jun 05


Hello All...

I recently mixed up a few hundred pounds of a homemade clay body. Out =
of my test clay, I have made a tile that measured 10 centimeters when =
wet. The tile is currently being fired to cone 10. When I unload the =
kiln, I will weigh the tile, then boil for an hour, then weigh the tile =
again. Is this the correct way to conduct an absorption test? =20

Also, is the shrinkage of the clay measured with the 10 centimeters test =
the measurement that I would use to determine if glazes will fit =
correctly? Any advice on how to test a homemade clay body would be =
appreciated.

By the way, the clay is an off white, no grog, cone 10.

thanks
Peter Coates
Oklahoma City

David Beumee on thu 16 jun 05


Hi Peter,
Please read my article on porcealin and stoneware bodies in the Dec. 2003 Studio Potter. I hope it will answer your questions, but please contact me if you need assistance.

David Beumee
Lafayette, CO










-------------- Original message ----------------------
From: Peter Coates
> Hello All...
>
> I recently mixed up a few hundred pounds of a homemade clay body. Out of my
> test clay, I have made a tile that measured 10 centimeters when wet. The tile
> is currently being fired to cone 10. When I unload the kiln, I will weigh the
> tile, then boil for an hour, then weigh the tile again. Is this the correct way
> to conduct an absorption test?
>
> Also, is the shrinkage of the clay measured with the 10 centimeters test the
> measurement that I would use to determine if glazes will fit correctly? Any
> advice on how to test a homemade clay body would be appreciated.
>
> By the way, the clay is an off white, no grog, cone 10.
>
> thanks
> Peter Coates
> Oklahoma City
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
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Ben Shelton on thu 16 jun 05


On Wed, 15 Jun 2005 17:21:22 -0500, Peter Coates wrote:

>Hello All...
>
>I recently mixed up a few hundred pounds of a homemade clay body. Out of
my test clay, I have made a tile that measured 10 centimeters when wet. The
tile is currently being fired to cone 10. When I unload the kiln, I will
weigh the tile, then boil for an hour, then weigh the tile again. Is this
the correct way to conduct an absorption test?

Yes,
This is how to test absorption. The math is also posted in the clayart
archives. Thank you Ron Roy.

>
>Also, is the shrinkage of the clay measured with the 10 centimeters test
the measurement that I would use to determine if glazes will fit correctly?


Well, Ron will tell you that clay bodys can have a measured shrinkage but
glazes are measured for coefficient of expansion. Others will have to advise
on matching a body to a glaze. It is beyond me atthe moment.

You are on the right trackt though. The body must be stable and vitrified
for strong ware.

I am doing some of this testing myself right now at cone 6. Will post my
results.

Ben


Any advice on how to test a homemade clay body would be appreciated.
>
>By the way, the clay is an off white, no grog, cone 10.
>
>thanks
>Peter Coates
>Oklahoma City
>
>______________________________________________________________________________
>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.