Joan Warren on fri 22 nov 96
Hi clayarters,
I am using a high manganese, high clay , bronze metallic "suicide" glaze which
up to yesterday has been very pleasing and successful for one of the forms I
make. The pots on the bottom shelf of my electric kiln were blistered- the rest
of the kiln was fine. I use a heavy application to achieve the bronze, which
means that it's almost like a thick skin when fired. I have a cone and a half
difference between top and bottom shelves which I have reduced somewhat by
turning the bottom switch on first when raising the temperature, before
switching the others on. My brain tells me the bottom shelf needs more soaking
to heal the blisters, and that I should fire down at the end of the firing, but
my brain also tells me that it doesn't want manganese poisoning breathing fumes
as I watch cones bend. I clear out of my studio when I fire this glaze and rely
on my kiln sitter. I've taken the article on manganese poisoning in the Feb.?
Contact (Canadian) magazine seriously. Any creative suggestions as to switch
manipulation to achieve a soak, or?
I really appreciate this group, and the fact that I can access the knowledge
out there!
Joan Warren
katepwa@raven.bc.ca
sent via UUCP from: Raven Net, Salt Spring Island, BC, Canada
Kirk Morrison on sat 23 nov 96
On 22 Nov 96 at 8:23, Joan Warren wrote:
> ----------------------------Original message----------------------------
> Hi clayarters,
> I am using a high manganese, high clay , bronze metallic "suicide" glaze which
> up to yesterday has been very pleasing and successful for one of the forms I
> make. The pots on the bottom shelf of my electric kiln were blistered- the re
> of the kiln was fine. I use a heavy application to achieve the bronze, which
> means that it's almost like a thick skin when fired. I have a cone and a half
> difference between top and bottom shelves which I have reduced somewhat by
> turning the bottom switch on first when raising the temperature, before
> switching the others on. My brain tells me the bottom shelf needs more soakin
> to heal the blisters, and that I should fire down at the end of the firing, bu
> my brain also tells me that it doesn't want manganese poisoning breathing fume
> as I watch cones bend. I clear out of my studio when I fire this glaze and rel
> on my kiln sitter. I've taken the article on manganese poisoning in the Feb.?
> Contact (Canadian) magazine seriously. Any creative suggestions as to switch
> manipulation to achieve a soak, or?
> I really appreciate this group, and the fact that I can access the knowledge
> out there!
> Joan Warren
> katepwa@raven.bc.ca
> sent via UUCP from: Raven Net, Salt Spring Island, BC, Canada
>
A friend good in electronics most likely could build you a timer
circuit using a timer chip and a few opto couplers that would once
tripped always turn on the lower elements for you, 2 turn it off last
and switch the others on always together. It would not cost that much
and you would never have to be near your suicide glazes. I don't think
the circuit would cost much over $75 using industirial parts.
Kirk
Robert Speirs, M.D. 766 X4450 on sun 24 nov 96
I am sorry not to have any advice for your blistering; however, I am in
the process of testing several high manganese metallic glazes and was
wondering if you would share your recipe with me to test as well. Also,
I am not aware of this manganese poisoning you refer to. Could you
bring me up to speed on this as well? Thanks.
Laura in Oregon
LINDA BLOSSOM on sun 24 nov 96
Dear Joan,
It is interesting that you say that you need a thick coat of glaze to
achieve the bronze look. I found a narrow window on that one. Too thin no
good and too thick no good. I would start with thickness tests placed
throughout the kiln with cone pats next to each one to determine whether
thickness or temperature was the culprit.
Linda Blossom
2366 Slaterville Rd.
Ithaca, NY 14850
blossom@lightlink.com
http://www.artscape.com
607-539-7912
"Rafael Molina-Rodriguez (Rafael Molina-Rodriguez)" on sun 24 nov 96
Joan :
I've had the same problem when firing this type of glaze on the bottom of
an ancient Paragon High-fire kiln ( square, top-loading ). This kiln has
approximately one cone differential from top to bottom. I solved the
problem of already fired pieces by refiring them in a hotter zone of the
kiln. The blisters disappearred. Now I place all bronze glazed pieces at
or near the top.
Here are two more bronze glazes you want to try :
Sandy Bronze ^ 6 Oxidation ( ^ 7 in sitter)
Ball Clay 20
Manganese Dioxide 80
Copper Carbonate 20
Note : Thin application for best color.
Ogden Bronze ^ 6 Oxidation ( ^ 7 in sitter)
Manganese Dioxide 60
Black Copper Oxide 10
Red Clay 20 ( I use Redart )
China Clay 10 ( I use EPK )
Note : A thick coat yields best results.
>>> Joan Warren 11/22/96 07:23am >>>
----------------------------Original message----------------------------
Hi clayarters,
I am using a high manganese, high clay , bronze metallic "suicide" glaze
which
up to yesterday has been very pleasing and successful for one of the
forms I
make. The pots on the bottom shelf of my electric kiln were blistered- the
rest
of the kiln was fine. I use a heavy application to achieve the bronze,
which
means that it's almost like a thick skin when fired. I have a cone and a
half
difference between top and bottom shelves which I have reduced
somewhat by
turning the bottom switch on first when raising the temperature, before
switching the others on. My brain tells me the bottom shelf needs more
soaking
to heal the blisters, and that I should fire down at the end of the firing, but
my brain also tells me that it doesn't want manganese poisoning
breathing fumes
as I watch cones bend. I clear out of my studio when I fire this glaze and
rely
on my kiln sitter. I've taken the article on manganese poisoning in the
Feb.?
Contact (Canadian) magazine seriously. Any creative suggestions as to
switch
manipulation to achieve a soak, or?
I really appreciate this group, and the fact that I can access the
knowledge
out there!
Joan Warren
katepwa@raven.bc.ca
sent via UUCP from: Raven Net, Salt Spring Island, BC, Canada
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