Lauren Bellero on wed 16 aug 06
>I had heard that using your kiln to dry your ware is also hard on the
>elements, is this true? If so, does using a vent alleviate this and
>keep the water vapor from doing harm?.
hi debi,
i used to do that ALOT. eventually, my enviro-vent (which
is mounted underneath the kiln) stopped working. when i
took it off and opened it up to look at it, it was
rusted to pieces! i'm sure they don't last forever,
but i think this practice of using the kiln to
dry the ware shortened its life. i don't know if
there is much of an effect on the elements, as i got
a respectable # of firings out of them, but
i'm looking forward to seeing what arnold says...
i still think it's necessary to candle the
ware just prior to the bisque, but it's a matter
of degree. initially, i would put real leather hard
ware in and 'dry' it in the kiln. now i only candle
for a couple of hours what looks to be already dry,
but might not be. i once put in work that looked
completely dry to me, but when i opened the kiln
after the bisque, many of the pieces had blown up
because the bottoms were not dry.
i've learned a good way (probably from clayart)
to help tell the dryness: if the piece looks
dry but feels cool (put it up to your cheek), then
it still has a potentially dangerous amount of moisture.
all the best,
lauren
--
Lauren Bellero, Mudslingers Pottery
http://mudslingerspottery.net
Red Bank, NJ
Richard White on thu 17 aug 06
I let my greenware dry as much as can before loading. If it feels even
slightly cooler than the room air temperature (which you can't sense in
your hands, you have to hold the piece against a more sensitive place like
your cheek or inside of your forearm, sort of the opposite of the mother's
test of the temperature of the baby's bottle...), then there is still
residual moisture that has not evaporated. However, even then there is
still some slight water in "dry" clay, which can blow up if you fire the
kiln too fast straight up from cold through the boiling point of water
(100C, 212F). After candling with the bottom element on low for a few
hours, plugs out, and the lid propped up slightly with a scrap of wood, I
hold a piece of mirror beside each spyhole and around the gap under the
lid. If there is still any water vapor escaping from the clay, it will
immediately condense on the mirror and you'll see it as a "breath cloud."
If the mirror shows no sign of vapor, then I start the firing.
dw
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