Jon Singer on thu 9 oct 03
In a recent posting, Craig Martell says that you have to use unwashed
wood ash extremely quickly, the same day you mix the glaze.
My experience runs counter to this claim, though I should note
that my glazes are somewhat different from the recipe that Sylvia
Mondloch gave in her original query, which Craig was responding
to. (She's using 40% ash and 20% clay; I'm typically closer to
20% ash and 70% clay.) I've kept some of mine around for months
and months, and they're just fine. A bit finicky about thickness of
application, perhaps, but no worse than a lot of other glazes I've
seen and used.
I _never_ wash wood ash, in fact. Washing the stuff seems to me
to be a huge pain in the neck and, at least for the types of glaze
I put it into (tenmoku & related things), totally unnecessary.
I do, however, sift it to at least -120 mesh, to get as much grit out
of it as I can. That, too is a huge pain in the neck; but I want my
tenmoku to have a nice smooth surface, and even a few unmelted
sand grains will mess that up in a hurry. (I get my wood ash from
people's fireplaces, and there's almost always a certain amount of
sandy junk in it, probably from the mortar between the bricks.)