TheClosetPotter@AOL.COM on fri 26 may 00
Hi.
I attended a Raku firing (my third) and brought along some recipes I mixed up
to try. Among them was a Copper Matt, or, perhaps, THE Copper Matt:
Frit 3110 10
Copper Carbonate 90
I added some CMC to help the mixture better adhere to the bisque for
transport after raw glazing which worked fine.
I used a sample piece on which I applied one, two and three thin coats of the
mixture. It all came out black as if the mixture completely fired out. I
was told that perhaps this recipe will only work when sprayed on. I wonder
if this is so; I hope not as I do not yet have the equipment to spray with.
While I have no idea at what temperature the kiln is fired to as the
temperature is not measured in any way, I do know that it is the melting or
maturing of the standard Clear (or White Crackle) glaze (80 gerstley/20
nepheline) which determines when all the pots are removed for reduction. Can
someone tell me at what temperature it is that the White Crackle matures?
I wonder if the temperature at which the White Crackle glaze matures is too
hot for the Copper Matt. I attend the Raku firings as part of a studio
workshop event and for best results should use Raku glaze recipes that mature
at the same time as the White Crackle.
Does anyone have any suggestions on how I might still be able to use the
Copper Matt successfully even at the same temperature as the White Crackle?
Or, perhaps someone might suggested another method of application?
Thanks in advance for any assistance.
Following are the other three glazes I mixed up and used at this Raku (I
realize that while they are not new recipes (except for Karen Shapiro's),
they are new to me and thought other's who are new to Raku might wish to have
the recipes and comments):
Blue Hawaiian Raku (CM, Sept. '98)
Gerstley Borate 80
Bone Ash 20
Tin Oxide 1.3
Copper Carbonate 5
Cobalt Oxide 2.5
This glaze reliably produced a lightly textured matt lustre capable of blues,
purples, reds and copper. It worked best for me when 2 thin coats were
applied (I reduced in newspaper). Everyone seemed to like the results so it
will likely become a staple for us.
Copper Emerald Green Raku (Steve Forbes-deSoule, Wheel Thrown Ceramics)
Frit 3134 43
Gerstley Borate 38
EPK 12
Flint 7
Copper Carbonate 6
This glaze produced a smooth, satiny lustre capable of a variety of colors.
Again, 2 thin coats (reduced in newspaper) gave good results but, on the test
piece, three coats was reflecting more of the Emerald color and I will try
using three coats next time. It wasn't used much so I don't yet know how
reliable it is; I'll try it again at my next Raku firing.
Killer Cobalt (Karen Shapiro/Clayart) (Thanks Karen!)
Gerstley Borate 75
Nepheline Syenite 25
Copper Carbonate 3
Cobalt Carbonate 6
Barium Carbonate 5
I used two coats and reduced in newspaper; the glaze went completely glassy
copper with no trace of blue. I will try using a thicker application next
time (keeping in mind that Karen described it as a runny glaze), and I will
try removing it from the reduction container sooner to prevent it from
completely reducing to copper.
Any suggestions on this glaze? I've never tried reoxidizing sections of a
pot with a blowtorch; does anyone use that technique, can describe it and
think it might be useful here?
Thanks again,
Linda Paul
TheClosetPotter@aol.com
Kew Gardens, New York
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