Dave Finkelnburg on thu 16 feb 06
Rachelle,
The glaze, as mixed, will make a nice celadon, perhaps a tiny bit different, but no more than if the RIO were weighed out 10% light. Yellow iron oxide (YIO) has about 90% Fe2O3. Red iron oxide(RIO) is about 100% Fe2O3.
However, IF it's critical to have precisely the same glaze result as from the original recipe, then yes, the pots should be washed off, a new glaze batch properly prepared, and the pots reglazed.
I have to ask, are you sure YIO was used and not yellow ochre? Yellow ochre is an iron-bearing clay with CaO, MgO that is only about 22% Fe2O3. It is yellowish (ochre). Yellow ochre would make a very big difference and produce a much lighter-colored celadon than RIO.
Good glazing!
Dave Finkelnburg, off to shovel snow on a sunny but single-digit temperature day in Idaho...
Rachelle Raphael wrote:
Someone in our studio recently made a Celedon IV glaze from a recipe and used yellow ochre instead of red iron oxide. Another potter just glazed a lot of porcelain pieces with this glaze before realizing it was a different color from the old Celedon IV (yellow vs. red in liquid form)
Does anybody know if this change is ok? What difference in final, fired
color, will this result in? We will test it soon but in the meantime should Susan wash her pots off?
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