Derek Hevel on mon 31 mar 97
Clayarters,
I'm interested in getting some of the metallic, rough, earthy surfaces I
would with metal oxides but am unsure of a couple of things. I want to get
a couple of ideas clear before I start so I don't end up blowing up my
school's studio (yes, I have permission to experiment...safely!).
--should they be mixed with water or something in order to
paint/dip them on to the ware? should this mix be pastey
or watery? I'm thinking I'll just brush on this mix...
--this mix can be applied before or after any firing, right? does it
matter at what cone it is used? maybe there are differences in
"maturation" of these oxides or something that I don't know about.
--what about toxicity of they oxides? is it safe to put this stuff in
any old oxidation kiln? is it bad to combine any particular oxides
for some hazardess chemical explosion?
So...I'm looking for answers to these questions and anyone's previous
experience with using oxides alone. Thanks so much in advance.
Derek from Oregon
Sylvia See on thu 3 apr 97
Hi Derek;
I can't answer all your questions about oxides as I am new to using them
on unglazed clay as well. However, a friend and I are into making castles
and we each finished one over the Easter holidays. She brushed her castle
with black iron oxide mixed with water and then used a sponge to wipe it
off the top surfaces, leaving the heavy oxide in the cracks and between the
shingles etc. I used the 4:1 ratio of manganese and copper carbonate on my
shingles and scratched areas and didn't wash it off. My combination of
manganese and copper carbonate I believe actually makes a glaze finish. It
was used extensively by Lucie Rie and it was from her book that I got the
ratio of the two ingredients. So some of the oxides act as a flux and can
make a glaze finish and some just color the clay. I think a good resource
of how the oxides work would be in Ceramic Spectrum by Robin Hopper. He
packs a ton of information into this book. Also where my friend just mixed
the black iron oxide with water to a thin mixture, I used water with a very
small amount of glycerine to help keep them from separating and packing on
the bottom. Some of the oxides I have tried have been almost impossible to
keep suspended in the water to brush on. However, I should add that this is
the first time I have used glycerine, and perhaps the two oxides I chose
would have dissolved fine in the water alone.
I really wanted to try red iron oxide on my castle but was unsure of the
results. I am firing them to cone 10 in an electric kiln, using cone 10
Raku clay which is off-white to buff unglazed. I love the clay for hand
building, but would like to get the effect of red clay. Does anyone know if
I can do this by brushing with red iron oxide, no glaze. I want the red
clay look with the black iron oxide in cracks and crevices, and shingles. I
would appreciate any response from someone experienced with oxides on light
colored clay.
Thanks in advance.
Sylvia See Claresholm, Alberta sylviac@telusplanet.net
I really like my bifocals
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