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clay/engobe/glaze microwave absorption question?

updated thu 5 apr 01


Rick Monteverde on wed 4 apr 01

Hi -

I need of a sort of radar stealth ceramic coating for a specialized
microwave oven cooking vessel.

Has anyone had any experience with using an engobe or glaze which
absorbs or reflects and therefore blocks microwave radiation to some
degree? I know some fired clay readily absorbs mw energy, and some,
like high fire porcelain, are quite transparent to it. My need for a
vessel for use in domestic microwave ovens which is basically mw
transparent in its clay body, but would have glaze and/or engobe on a
section where the contents of the vessel there are to be to a degree
shielded from the microwaves. I'm hoping for cone 5-6 as a glaze
firing temperature, but whatever works would be considered. Complete
shielding is not necessary, but a substantial reduction would be
good. Absorbtion, reflection, or both are methods which could be used
to use to attenuate the energy entering the vessel. Also, making a
surface covered with cone-like protrusions coated with the mw
reacting surface would be another thing I could do if it would help -
design-wise that would be fun anyway. I don't want to use something
that is only strongly reflective as in a metal shield - bad for the
oven? - or only strongly absorptive, because of too much heat buildup
in the walls. Ferrous engobes and glazes come to mind, but what
recipes and thicknesses?

Anyone with experience making ceramics specifically for microwave
oven use out there, I would appreciate any suggestions or hints you
might have come across. How about anyone from Northrop or un-named
Air Force facilities in Nevada? Really, you wouldn't have to
kill me, nobody else needs to know!


- Rick Monteverde
Honolulu, HI