[Clayart] aligning the platelets [GroupMail]

William & Susan Schran User wschran at cox.net
Mon Jan 20 10:31:50 EST 2014


You are correct Ivor.
In the first link, "Electron Microscopy of Clay Surfaces”, the authors
describe several limited minerals in the sample.
Included are: kaolinite, dickite (never thought I’d see a name like this
in pottery), halloysite, montmorillonite and attapulgite.
They describe the kaolinite as “parallel” and in “sheets” while the other
minerals are “tube” and “fiber” in nature.
The samples used in this study were of raw clay.
We use a blended clay and most likely the clay body contains multiple
minerals that contribute to its working/firing characteristics.
Whether these additional minerals contribute much to the strength of the
clay while it is worked on the potter’s wheel, I don’t know.

Bill
-- 
William "Bill" Schran
wschran at cox.net
wschran at nvcc.edu
http://www.creativecreekartisans.com



On 1/20/14, 12:35 AM, "ivor and olive lewis" <iandol at westnet.com.au> wrote:

>
>Dear Willliam,
>An interesting collection of images. Prof. R. E. Grim has similar images
>in 
>Clay Mineralogy and also drawings from live observations. There is even
>an 
>EM image in Lawrence and West, " Ceramic Science for the Potter".
>Unfortunately such Electron Microscope images are little use when
>attempting to make sense of the nature of Potter's Clay, For example,
>thre 
>is no attempt by authors or teachers to distinguish between Kaolinite and
>the other minerals, such as Halloysite (Is it really used in fine
>porcelaine 
>bodies. Its basic shape is needle like ! ) or Bentonite (A volcanic
>powder 
>that can adsorb several times its own volume of water ! )
>
>Sincere regards,
>Ivor Lewis,
>REDHILL,
>South Australia
>
>
>
>Robert,
>I have seen several electron microscope images of clay and in each
>instance there were indeed platelets, flat shapes with irregular edges,
>some stacked together some scattered and independent.
>
>Here are some interesting sources:
>http://www.clays.org/journal/archive/volume%203/3-1-1.pdf
>http://www.clays.org/journal/archive/volume%2019/19-1-49.pdf
>
>There¹s a great image of clay particles on this page:
>http://watchingtheworldwakeup.blogspot.com/2010/03/dangers-of-riding-on-cl
>a
>y.html
>
>Bill
>-- 
>William "Bill" Schran
>wschran at cox.net
>wschran at nvcc.edu
>http://www.creativecreekartisans.com
>
>
>
>On 1/19/14, 10:33 AM, "Robert Harris" <robertgharris at gmail.com> wrote:
>
>>In fact I have seen a number of ceramic scientists (who have take
>>electron
>>micrographs) more or less say that within a plastic clay body (a mixture
>>of
>>at least 4 different materials) the evidence for "platelets" existing at
>>all is rather slim (as potters might conceive them, of particles that can
>>be manipulated to line up). They are, more or less,  an invention of the
>>potter seeking to explain precisely what we are talking about.
>
>
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>





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