peter h. pache on sat 7 nov 09
Anyone have any pros/cons on Matt & Dave's "Porcelain for the People"?
(see at: http://www.mattanddavesclays.com/index.html)
Thanks -
Peter H. Pache
Datil, NM
ivor & olive lewis on wed 11 nov 09
Dear Peter H. Pache,
You asked, "Anyone have any pros/cons on Matt & Dave's "Porcelain for the
People"?
No experience with their product but they give an interesting presentation.
Given that a plastic clay with a bit of tooth will have blocky particles at
least half a millimetre across say about 500mu, that minus 200 mesh milled
silica and felspar is in the order of 60 mu with a block form and that the
clay mineral will be in the range of 2mu to 0.1mu and be in the form of
flakes, which is not made clear, it would be interesting to know how well
packing may vary from their illustration of an ideal model of maximum
packing density.
Their hypothesis is a good one. But I wonder if it is validated by their
evidence.
In discussions about the nature of plastic clay I always come back to ideas
about Volumetric relationships. In a plastic clay, one that is firm may hav=
e
(by mass) 20% water and 80% solids. A sample which is soft could be (by
mass) 30% water and 70% solids. But if these are converted to volumetric
measure there is enough water in both to prevent contact between solid
particles. A deflocculated casting slip which flows freely may have less
than (by mass) 15% water.
What are your thoughts ?
Best regards,
Ivor Lewis,
Redhill,
South Australia
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