(Linda Mueller) on wed 9 sep 98
I'm an old potter who hasn't read much about tech stuff and doesn't know what
damp dust is. Please explain.
Cameron Harman on thu 10 sep 98
Linda,
It seems that in every endeavor there are people who don't know
the terms so they make up their own. Others, also not knowing,
carry on those terms.
The term 'dust' is used by British ceramists to denote a
relatively fine power and, therefore has been extrapolated to
cover even the coarser powders currently used for ceramic powder
pressing. In the US we refer to 'dry' pressing to indicate a
'damp' powder.
In the U.S. the correct term is 'dry pressing', which means a
processed ceramic in a free flowing state containing about 5 to 6%
water. It is not really dust, however, since the powders are
usually relatively coarse due to the spray drying process very
often used. The really fine powders fly around too much and will
not compact properly in a press, since the entrained air cannot
easily get out while the press is squeezing the ceramic.
The term 'dry pressing' is used as a contrast to 'wet pressing'
which was very frequently used many years ago.
Soooo, damp dust is really dry pressing which is really pressing a
prepared ceramic powder containing about 5 or 6% water.
Cameron Harman
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