debkaplan3 on mon 22 jan 01
Hi all
I like the effect that my cone 6 oxidation glazes have when I add glass
sprinkled over the dried glaze & fire. However, I sometimes get craters,
bubbles & crackling of the glass. Does this render the piece
non-functional? I realize that bits of food may lodge in the crevices, but
my use of these plates has never created a bacterial breeding ground that I
can discern. Seems like the soap & hot dishwasher get it clean. My BS is
in Microbiology so I know that you can swab just about any surface & get
some growth. My question is are these plates really "safe" to sell? What
do my more experienced colleages say? Is there any guidelines or testing
that can be done?
Thanks
Debbie
Cindy Strnad on mon 22 jan 01
Hi, Debbie,
We did swabbing for microbiology in nursing school. The biggest surprise for
me was when we did a doorknob and got hardly anything. I guess the doorknob
was just too smooth, hard, and dry for anything (or at least, anything we
could detect) to survive on it. I'm sure encapsulated viruses could make it,
but they don't show up much in a petri dish.
If you wash your plates in hot water, or water with a bit of bleach, I'm
sure they're quite safe. As long as they're kept clean, any bacteria they're
likely to breed will be the stuff you've got around anyhow, but you know
that.
As for selling them, well, it's your call. I think I'd be uncomfortable with
selling marred, rough surfaces as functional for moist food, but I don't
know that I'd be uncomfortable with *you* doing it. Heck, people sell much
worse. I'm sure you can pick up a low-fired mug at your local dime store
that will craze in a couple of months. The vast majority of people will go
right on using the crazed mug in their microwave ovens. Is that safe?
Your wares are probably safer than that $3.00 mug, at least. I'd just feel a
little reticent about declaring them functional. I'm not really sure why.
Logically, it's really all right as long as the piece *can* be kept clean,
even if it does take a bit of extra effort. Presumably the customer can see
that extra effort will be needed when he buys the plate.
Cindy Strnad
Earthen Vessels Pottery
RR 1, Box 51
Custer, SD 57730
USA
earthenv@gwtc.net
http://www.earthenvesselssd.com
debkaplan3 on tue 23 jan 01
Tom, Cindy and all
My students love putting the glass on their plates for the beautiful colors
& interplay with the glaze. I'm trying to determine advice that I should
give to them ie use with food? ..candy dish only? I would like to sell my
larger platters with the glass effect & am concerned about safety more than
saleability.
I'm looking at one of my plates with the glass & the glass surface is
smooth. I can see crackling in the glass but if I run my finger nail over
the glass there are no indentations or cracks. No sharp surfaces. This
plate would be ok to sell??? ...use with food?? I have some plates
(different glaze, different glass) with bubbling & little volcanos. I would
feel uncomfortable about selling these (I wouldn't sell them) but what
advice do I give my students? Don't use with food, candy / peanut dish
only???? My students don't sell their work.
I find the idea of imbedding the glass in the clay & then bisque fire very
interesting. I can't wait to try it. The glass will only melt about 50%
upon the bisque firing but then the glaze would be applied over this glass
then fired to cone 6 possibly making a smooth "first class surface".
Thanks for your advice
Debbie
-----Original Message-----
From: Tom Buck [mailto:Tom.Buck@hwcn.org]
Debbie:
In my world, such imperfections on the plate's top surface would
make it unsellable, let alone being a second. also you may have sharp
pieces sticking up and someone could cut themselves on it.
perhaps if you were to imbed the stained glass small pieces deeper
so its gets incoporated into the body, then a clear glaze would let the
coloured glas show through and yet be first class.
good pots. peace. tom b.
-----Original Message-----
From: Ceramic Arts Discussion List [mailto:CLAYART@LSV.CERAMICS.ORG]On
Behalf Of Cindy Strnad
Hi, Debbie,
As for selling them, well, it's your call. I think I'd be uncomfortable with
selling marred, rough surfaces as functional for moist food, but I don't
know that I'd be uncomfortable with *you* doing it.I'd just feel a
little reticent about declaring them functional. Logically, it's really all
right as long as the piece *can* be kept clean,
even if it does take a bit of extra effort. Presumably the customer can see
that extra effort will be needed when he buys the plate.
Autumn Downey on tue 23 jan 01
A little glass might not be too bad, but I made something once that I hoped
would give a mirror-like effect - by melting a layer of glass on top of a
dark surface. (Didn't really work, by the way). OVer about 10 years, this
had not only cracked but produced a dusty white powder - devitrification?
So, there could longer term effects of using glass as well. Might be good
to keep something around and watch for any changes. All glass is not the
same either, I don't suppose and I don't remember what I used, so no help
there.
Autumn Downey
Yellowknife, NWT
>Hi all
>
>I like the effect that my cone 6 oxidation glazes have when I add glass
>sprinkled over the dried glaze & fire. However, I sometimes get craters,
>bubbles & crackling of the glass. Does this render the piece
>non-functional? I realize that bits of food may lodge in the crevices, but
>my use of these plates has never created a bacterial breeding ground that I
>can discern. Seems like the soap & hot dishwasher get it clean. My BS is
>in Microbiology so I know that you can swab just about any surface & get
>some growth. My question is are these plates really "safe" to sell? What
>do my more experienced colleages say? Is there any guidelines or testing
>that can be done?
>
>Thanks
>Debbie
>
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melpots@pclink.com.
>
>
John Hesselberth on tue 23 jan 01
debkaplan3 wrote:
> My students love putting the glass on their plates for the
>beautiful colors
>& interplay with the glaze. I'm trying to determine advice that I should
>give to them ie use with food? ..candy dish only? I would like to sell my
>larger platters with the glass effect & am concerned about safety more than
>saleability.
> I'm looking at one of my plates with the glass & the glass surface is
>smooth. I can see crackling in the glass but if I run my finger nail over
>the glass there are no indentations or cracks. No sharp surfaces. This
>plate would be ok to sell??? ...use with food?? I have some plates
>(different glaze, different glass) with bubbling & little volcanos. I would
>feel uncomfortable about selling these (I wouldn't sell them) but what
>advice do I give my students? Don't use with food, candy / peanut dish
>only???? My students don't sell their work.
> I find the idea of imbedding the glass in the clay & then bisque
>fire very
>interesting. I can't wait to try it. The glass will only melt about 50%
>upon the bisque firing but then the glaze would be applied over this glass
>then fired to cone 6 possibly making a smooth "first class surface".
>Thanks for your advice
>Debbie
Hi Debbie and others.
You have asked a question that is impossible to answer with other than
opinion. For example have you tested the resulting product for shivering
and crazing? Your glaze and glass could have remarkably different
expansions. Shivering, if it occurs, can put dangerous slivers of glass
in a person's mouth. What was in the glass you used? By any chance was
it a leaded glass? If so, does lead now leach from the glaze/glass
combination?
Unless you can answer these kinds of questions, I don't think you should
be doing this on food surfaces. There are just too many undefined and
uncontrolled factors.
Regards, John
"The life so short, the craft so long to learn." Hippocrates, 5th cent.
B.C.
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