Laura Conley on mon 26 jan 98
Raku enthusiasts,
I have done some experimenting with raku glazes during the last year, and
will not be pursuing this research in the near future, so I wish to share the
info with all of you, in the event that some are interested.
I was trying to create some new colors, and it occured to me that 5 cent
nickels might lead to a good glaze... So I put some black nickel oxide in a
raku base glaze that I had, and ... silver and gold! Now, it should be
clearly stated that #1 these results were inconsistent - more than other raku
glazes. Clearly this glaze needs a very good reduction. #2 the studio I was
at fired the raku pots to 2000-2100 F. This is much hotter than the normal
raku temp. I have never done the test of putting a pot back into the oven to
see if I can get it to reoxidize (copper does at 400F or so). This means
that it is possible that the temperature at which the nickel reduces/oxidizes
might be quite high, close to the top temp, and this is why it is hard to get
the colors.
This is what I know about the colors. The glaze is brown in oxidation. I
tried 5% and 10%. When heavily reduced it turns silver. When less heavily
reduced it appears gold - light silver over the brown glaze. I have tried
this glaze with small additons of other oxides, such as cobalt. In small
amounts the cobalt causes a purplish tinge in the silver. I have not seen
strong rainbows in the glaze, but I have never tried to torch a heavily
reduced section to see what would happen.
Good luck to anyone wishing to pursue this! It really is quite pretty, and I
think much cheaper than silver nitrate, etc. I can try to answer questions
if there are some...
Laura Conley
Boulder, CO
Diana Mannino on tue 27 jan 98
ORIGINAL MESSAGE:
> Raku enthusiasts,
>
> I have done some experimenting with raku glazes during the last year, and
> will not be pursuing this research in the near future, so I wish to share the
> info with all of you, in the event that some are interested.
>
> I was trying to create some new colors, and it occured to me that 5 cent
> nickels might lead to a good glaze... So I put some black nickel oxide in a
> raku base glaze that I had, and ... silver and gold! Now, it should be
> clearly stated that #1 these results were inconsistent - more than other raku
> glazes. Clearly this glaze needs a very good reduction. #2 the studio I was
> at fired the raku pots to 2000-2100 F. This is much hotter than the normal
> raku temp. I have never done the test of putting a pot back into the oven to
> see if I can get it to reoxidize (copper does at 400F or so). This means
> that it is possible that the temperature at which the nickel reduces/oxidizes
> might be quite high, close to the top temp, and this is why it is hard to get
> the colors.
>
> This is what I know about the colors. The glaze is brown in oxidation. I
> tried 5% and 10%. When heavily reduced it turns silver. When less heavily
> reduced it appears gold - light silver over the brown glaze. I have tried
> this glaze with small additons of other oxides, such as cobalt. In small
> amounts the cobalt causes a purplish tinge in the silver. I have not seen
> strong rainbows in the glaze, but I have never tried to torch a heavily
> reduced section to see what would happen.
>
> Good luck to anyone wishing to pursue this! It really is quite pretty, and I
> think much cheaper than silver nitrate, etc. I can try to answer questions
> if there are some...
>
> Laura Conley
> Boulder, CO
>
Hi Laura,
Your raku ideas are great...just want to add for those who are as
ignorant as I WAS, that nickel is one of THE MOST DANGEROUS oxides to
work with. I once bought a bunch of oxides and just 'played' with them
not realizing that some are extremely hazardous.
There is a great site listing all oxides and chemicals, their properties
and health hazards:
http://www.epa.gov/enviro/html/emci/chemref/
It's worth the time....
Diana
Cortona,
Italy
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