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Posted by charlie on March 6, 2008, 1:36 pm
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>>wrote:
>>
>>>>On Tue, 4 Mar 2008 22:20:30 -0600, "The Splanns"
>>>>
>>>>>Hi everyone!
>>>>>I've been reading the post for some time and I have a question too. Has
>>>>>=
>>>>>anyone ever made anything with copper inlay? How exactly would copper =
>>>>>act in cone 6 glaze firing? I would greatly appreciate your advice or =
>>>>>even a reference to where I can find more information on a subject.
>>>>>Thanks,
>>>>>Veronika
>>>>
>>>>Copper won't survive at cone 6. It melts at 1984F (1084C), which is
>>>>roughly cone 03, but it oxidizes like crazy long before that. If you
>>>>were making flat tiles, you *might* be able to get it up to melting by
>>>>covering it with a protective flux, but I imagine this would take some
>>>>amount of experimentation to get working.
>>>>
>>>>This seems to be generally true of all common metals in oxidizing
>>>>atmospheres... they oxidize long before they get to melting.
>>>>I don't know if you could get decent melting in a fuel kiln fired in
>>>>reduction, but I bet it wouldn't be easy... you'd have to keep it in
>>>>reduction throughout the whole firing cycle.
>>>>
>>>>Best regards,
>>>>
>>>>
>>>>Bob Masta
>>>>
>>>> DAQARTA v3.50
>>>> Data AcQuisition And Real-Time Analysis
>>>> www.daqarta.com
>>>>Scope, Spectrum, Spectrogram, FREE Signal Generator
>>>> Science with your sound card!
>>>
>>>
>>>This is a question I've often wondered about for many years and never
>>>got around to asking. Glad it's turned up now. Given that the copper
>>>oxidises long before melting, would it leave sufficient traces of oxide
>>>at lower earthenware temperatures when it could, maybe, be used as glaze
>>>colourant as part of design. Would it always produce copper oxide, or
>>>would that depend on kiln atmosphere? Can any other metals be used in
>>>this sort of way? Hope you can follow my thinking - I have a bad cold
>>>and a fuddled brain. Thanks
>>>
>>
>>I only have personal experience with oxidizing (electric) kilns.
>>I think you could probably get this to work, and it might make
>>an interesting effect, at least for non-functional ware. The copper
>>or iron (steel) that I've fired invariably oxidize to black, but I
>>haven't put them next to a glaze. I'd expect the oxides to bleed
>>into the glaze at the edges of the original metal, perhaps
>>giving a green halo around the black copper oxide lump.
>>Might be fun to experiment with different base glazes to see
>>which promotes the most bleeding.
>>
>>If you covered the metal with the glaze application, it should
>>reduce the oxidation when the glaze becomes fluid enough
>>to block oxygen from getting to the metal. So there may be
>>some interesting effects with different thicknesses, as well
>>as different glaze melting temperatures. Try flat tiles at
>>first, so you can over-fire the glaze and not worry about
>>it running off the piece.
>>
>>And please report back with your results!
>>
> Hi Bob
>
> I don't make anything useful at all, so no problem there. I'm not working
> at the moment but will give this a go when I get going again. There may
> also be some ironstone clay which I can dig out of the ground on a
> friend's farm, so that's going to be something to play around with. What
> might the firing range of ironstone be?
>
> Thanks for your thoughts.
>
> Susie, Isle of Arran, Scotland
> --
> Susie Thompson
> If you can't stand the heat, don't tickle the dragon
> to email me replace "deadspam" with my name
i have experience with copper during glass fusing, around the 1500F temp
range. if you coat copper with a clear ferro glaze or a borax film, you'll
tend to have shiny copper in that range. uncoated, you can get anything from
black to green to pink, depending upon how much O2 gets to it when it's
heating. if you can isolate it from O2, you tend to get more coppery colors.
regards,
charlie
http://glassartists.org/ChaniArts
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