Nils Lou on sat 5 jan 02
One of my students at Alfred recently informed me of his discovery that
clay mixed with barium interfered with soluable salts migrating to
surface. It seems to form a particulate that prevents that from happening.
Having the sodium move to the surface to flux is basic to the process I
used with a grolleg based porcelain. I didn't realize that barium would
act to discourage the process. It explains why some clays "work" and
others not. Barium is added to some clay bodies by manufacturers to
prevent "scumming". Not a bad thing, but explains the variable results
some have had in trying to duplicate my efforts to get cone 10 orange by
sodium soaking bisqued porcelain. See archives for more information if you
are interested in the process. I wrote an article on it for CM, forget the
issue, though. nils
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