Michael Hart on wed 10 feb 99
Hello all,
My husband and I replaced the elements in our L&L Kiln. The good news
is that it fired beautifully (^6)(I could dance and sing!) The bad news
is I think I overfired it a bit. Cone 7 was starting to bend...
(Before we changed the elements it was all I could do to get cone 6 to
bend.) Anyway some of my glazes ran off the pots. They are beautiful
and the firing was extremely successful except for this. I have used
these glazes before without problems. I wax the bottoms and leave about
1/4" of wax around the pot which I sponge to remove any heavy drips etc
before I place them in the kiln but they still ran. Some right to the
shelf...
My question is this: Is there any way I can grind the glaze off and
have the pots still look alright? How do other potters handle this? I
imagine crystaline glazes must run like crazy...how do you handle the
drips... Not all of the pots ran to the shelf, some have "drips" of
glaze around the bottom. Do you leave these or try to grind them?
I would appreciate any information and thank you in advance. I learn a
lot from Clayart...and experiences like this!
Thanks again,
Sid
in Ossipee New Hampshire (overheard referred to as "North Nowhere")
Marcia Kindlmann on fri 12 feb 99
Subject: glazes running off pot
Sid in Ossipee NH asks,
> Is there any way I can grind the glaze off and
>have the pots still look alright?
Depends on what you mean by alright. The color of the glaze won't be
the same -- interior of glaze is often grey, at least on those I've
ground off. But sometimes those runny glazes do look delicious and make
you want to salvage that pot. It takes a lot of time, and careful
work, and safety goggles, to use a grinding wheel. And water, to keep
it cool and keep down the health-hazardous silica dust (wear mask too.)
Vince Pitelka posted a thorough description on these safety matters
awhile back. A bench grinder is what Vince was talking about, i.e. a
grinder mounted to a workbench; usually has two different wheels,
different coarseness of grits. A bench grinder is about the only way
you can remove any serious amount of glass around the bottom of a pot
without the process taking forever. Depends on how much time you want
to spend to 'save' those pots. And even working with a bench grinder
is slow, careful work. You want to keep _carefully_ checking the
contours to be sure that a sharp edge doesn't remain that'll cut
somebody's fingers. Careful now, besides sharp, that pot in the grinder
can get hot.
The result -- if you've gotten it nice n'smooth, you'll have a pot that
_looks_ like it was ground. What will your customers think? If it's a
crystalline glaze of course people expect these glazes to run; those
pots are presented in attractive dark wooden carved & footed bases,
sort of like coasters that enclose the bottom, to hide the having-been-ground
aspect.
But if it's a 'regular' (not crystal glaze) pot, then you have what will
probably be considered a 'second,' but oh what a beautiful second.
There are some customers who understand enough about process and the
ways of the fire that they can love these pots for what they are.
Others may say (to themselves, but you can see it on their faces) "ick."
If your glaze drips are fat droplets that _didn't_ stick to the kiln
shelf, ah then you have what people with a Japanese or Chinese-inspired
aesthetic will ooh & ah over.
One last caution -- if any of these pots are meant to hold water, test
them to see if they really do. (overnight, on a paper towel; is there
any dampness). I do this when I have a tall vase with glaze that ran on
the kiln shelf, because when the clay shrinks as it cools, the glaze
sticking to the kiln shelf can prevent the pot from shrinking. That
will crack the pot. It might be a hairline crack you can't see, but
that pot will seep.
Take care,
Marcia in CT
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