Gary Ferguson on wed 3 nov 04
Al:
Your rust (I'm assuming a copper rust) should be the result of reduction. So
I would make sure you are not firing in reducton or conduct a much lighter
post-firing reduction (holding the piece in the air between the kiln and the
reduction chamber for 30-60 seconds).
One other thing you can try, to a still warm, all copper piece, is to use a
small blow torch and re-oxidize parts of the piece. This can give you
patches of rainbow colors. Just don't aim the flame in one particular spot
for too long.
I've seen this technique used to create oval patches that resembled a
peacock feather.
Good Luck,
Gary Ferguson
Raku Clay Artist
Nampa, ID 83687
Raku Gallery at: http://www.garyrferguson.com
300+ Glaze Collection at: http://www.rakuglazes.com
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Al Strauss on wed 3 nov 04
I have not been able to successfully produce a very colorful surface when
using copper matte glazes. I get surfaces that look like rust with an
occasional small spot of color. I have tried recipes with copper carb.
ranging from 10% to 90%. I fire in an electric kiln and have tried firing
over a temperature range of 1700 - 1900F, I have tried variations of
temperature drop before reducing, I have tried reducing in paper and
sawdust in a well-sealed trash can for short and long periods. I have
tried burping. I do successfully reduce glossy and shiny patina surface
glazes. Any ideas? help would be greatfully appreciated.
Desperate!!
Al Strauss
Christy Pines on wed 3 nov 04
My experience with copper matte glaze is to do alcohol reduction - fire to around 1700 F., pull, spray heavily with 90% isopropal alcohol, then put in a redution chamber with small amounts of burnables that will produce carbon (pine needles), seal and wait for the colors to appear. Sometimes requires a "burp" and an additional spray of alcohol.
christy
cpines at ix.netcom.com
Al Strauss wrote:
I have not been able to successfully produce a very colorful surface when
using copper matte glazes.
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