Stephani Stephenson on sun 15 apr 01
Just a historical note, on binders and raw materials:
I was reading John Kenny's "Complete Book of Pottery Making",
copyrighted in 1949.
He mentions that
" Native Potters of North Carolina use (red lead) mixed with molasses to
hold it on the ware."
(Though that is definitely in the " don't try this at home!" category,
it does give quite a perspective !)
Kenny goes on to say
"This seems to contradict what we said about the three essential
ingredients of glazes, (flux, alumna, silica) but actually it does not,
for during the fire the lead dissolves some of the clay of the pot it
is on and the glaze gets its alumina and silica that way"
This statement makes me think about why raw glazing in general has been
so UNproblematic for me so far!
Do the glaze layer and clay body actually interact more in single
firing, i.e. when one starts with unfired ware vs. bisque fired ware?
Are molecules from the clay body more available for interaction,
because they are not tied up in the already fired bisque?
Therefore, even at cone 04, is the fusion layer between clay and glaze
greater on raw glazed vs. bisque glazed ware?
Or is it that the interactions can start at a lower temperature, as
molecules in components with lower melting temps, in both glaze and clay
cross respective 'boundaries' to exchange ions?
It seems to me that there is a difference, from my own observation, but
would like to understand it more.
If this is true, would it not follow that the so-called exchange or
'absorption' of elements from clay to glaze or vice versa, also and
incidentally improve the fit , i.e. compatibility of glaze and clay
body?
I guess my question is
If the glaze I put on raw ware can absorb elements from the claybody
during the firing (or vice versa) wouldn't this in itself improve fit?
And does this happen more so in raw firing?
(Please excuse my fumbling with the terms, but this question plopped
unbidden from brain to keyboard after I typed Kenny's comment! I would
love to hear comments on Kenny's statement and also above questions from
those with a more complete grasp of the process !)
bye now
Stephani Stephenson
Alchemie Studio
Leucadia, CA
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