Anne POSSOZ on wed 26 jul 00
In a quite crazy study of copper red in electric kiln, I would
like to find out if there is anybody who has tried reduction
with silicon (not silicon carbide).
If this is the case, I would like to exchange privately before,
I hope, making a report for all interested people.
As far as I can say, there is nothing I could read, either on the
web or in the litterature, on that subject.
Anne
--
Anne Possoz Service Informatique Central Tel : (41/21) 693.22.49
Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland)
Sharon31 on thu 27 jul 00
Hi!
I think, you got it wrong!
What cause the local reduction, is the carbon, late us say, like in raku
firing, when you don,t let the oxygen to be around in the reduction box and
force the glaze to be carbonized! The point, as I understand, is that it is
pretty strong connection between the Si and the C (SiC) that keeps conncted
at least until ^6! When I got reduction in ^6 ox, it was with 100# SiC, and
real local, like sand, wherever the "sand" was.
Ababi
sharon@shoval.org.il
http://www.israelceramics.org/main.asp?what=gallery
http://www.milkywayceramics.com/cgallery/asharon.htm
----- Original Message -----
From: Anne POSSOZ
To:
Sent: Wednesday, July 26, 2000 04:12
Subject: electric reduction with silicon
> In a quite crazy study of copper red in electric kiln, I would
> like to find out if there is anybody who has tried reduction
> with silicon (not silicon carbide).
>
> If this is the case, I would like to exchange privately before,
> I hope, making a report for all interested people.
>
> As far as I can say, there is nothing I could read, either on the
> web or in the litterature, on that subject.
>
> Anne
>
> --
> Anne Possoz Service Informatique Central Tel : (41/21) 693.22.49
> Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland)
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
iandol on fri 28 jul 00
Anne Possoz made a very strong statement and was very sure about what =
she wanted to know. Anne wants to use pure silicon, a semi metal, as a =
reducing agent. If she has a cheap source in powder form this may make =
good sense. Since it is in the same chemical group as Carbon there is a =
possibility it will work.
There are other precedents. Aluminium and Magnesium are used to reduce =
oxides the metallic state. The Thermit welding process uses Aluminium to =
reduce Red Iron Oxide. Magnesium powder will reduce silver nitrate to =
silver.
Since these reactions can be very violent I would say, take great care =
and work very small to begin with. Use milligrams on small tiles
Anne POSSOZ on mon 31 jul 00
> Anne Possoz made a very strong statement and was very sure about what she
> wanted to know. Anne wants to use pure silicon, a semi metal, as a reducing
> agent. If she has a cheap source in powder form this may make good sense.
> Since it is in the same chemical group as Carbon there is a possibility it
> will work.
>
> There are other precedents. Aluminium and Magnesium are used to reduce oxides
> the metallic state. The Thermit welding process uses Aluminium to reduce Red
> Iron Oxide. Magnesium powder will reduce silver nitrate to silver.
Thanks Iandol for your support.
Of course, there are reasons to try it. I get some reds. I want
to understand more by sharing with others, if possible.
Maybe we still can learn something...
Some results are so surprizing... And I never made any copper
red before.
For interested readers, see the end of this reference:
http://digitalfire.com/education/glaze/copperred.htm
Copper Red Glazes
"Elemental Si is something that should be tried as an in-glaze reducing agent.
Maybe someone's already done it. It's cheap,
widely available - especially to those who live near a steel works - and very
potent in its effects. The advantages of Si as a
reducing agent are several fold, but the big one it that you can melt with
more correct combustion, and a few grams of Si has
always been a lot cheaper than 6 or 7 hours of bad combustion."
Si added in a glaze will provide internal reduction.
I am not an expert in chemestry but here is what I understand.
Si wants to become SiO2 so it will reduce the CuO, something
like:
Si + 2CuO ---> SiO2 + 2Cu
Why trying Silicon instead of silicon carbide? Because the process
is different and I am interested in trying (I did not invent it
myself but somebody advice me to try). With SiC there will be
CO2 having to escape from the glaze which is not the case with Silicon.
>
> Since these reactions can be very violent I would say, take great care
> and work very small to begin with. Use milligrams on small tiles
How could Si give a violent reaction? Any reference for that?
Sorry if the tone of my mail seems harsh. It is not my intention.
Unfortunately, I have very few time to devote to pottery as it
is not my work.
Anne
--
Anne Possoz
http://slpc7.epfl.ch/~possoz
ch. de Bonne-Esperance 17
CH 1006 Lausanne SUISSE
E-Mail : Anne.Possoz@epfl.ch
Tel+fax+rep : (41/21) 728.53.45
Sharon31 on mon 31 jul 00
Hello Ann!
The inly time I make real reduction, is in Raku as my big kiln is elctric
one. Try this artical in The Studio Potter.
http://www.studiopotter.org/articles/art0003.htm
I did not read it but the pictures look good.
Ababi
sharon@shoval.org.il
http://www.israelceramics.org/main.asp?what=gallery
http://www.milkywayceramics.com/cgallery/asharon.htm
----- Original Message -----
From: Anne POSSOZ
To:
Sent: Monday, July 31, 2000 01:45
Subject: Re: electric reduction with silicon
> > Anne Possoz made a very strong statement and was very sure about what
she
> > wanted to know. Anne wants to use pure silicon, a semi metal, as a
reducing
> > agent. If she has a cheap source in powder form this may make good
sense.
> > Since it is in the same chemical group as Carbon there is a possibility
it
> > will work.
> >
> > There are other precedents. Aluminium and Magnesium are used to reduce
oxides
> > the metallic state. The Thermit welding process uses Aluminium to reduce
Red
> > Iron Oxide. Magnesium powder will reduce silver nitrate to silver.
>
> Thanks Iandol for your support.
> Of course, there are reasons to try it. I get some reds. I want
> to understand more by sharing with others, if possible.
> Maybe we still can learn something...
> Some results are so surprizing... And I never made any copper
> red before.
>
> For interested readers, see the end of this reference:
> http://digitalfire.com/education/glaze/copperred.htm
> Copper Red Glazes
> "Elemental Si is something that should be tried as an in-glaze reducing
agent.
> Maybe someone's already done it. It's cheap,
> widely available - especially to those who live near a steel works - and
very
> potent in its effects. The advantages of Si as a
> reducing agent are several fold, but the big one it that you can melt with
> more correct combustion, and a few grams of Si has
> always been a lot cheaper than 6 or 7 hours of bad combustion."
>
> Si added in a glaze will provide internal reduction.
> I am not an expert in chemestry but here is what I understand.
> Si wants to become SiO2 so it will reduce the CuO, something
> like:
> Si + 2CuO ---> SiO2 + 2Cu
>
> Why trying Silicon instead of silicon carbide? Because the process
> is different and I am interested in trying (I did not invent it
> myself but somebody advice me to try). With SiC there will be
> CO2 having to escape from the glaze which is not the case with Silicon.
>
> >
> > Since these reactions can be very violent I would say, take great care
> > and work very small to begin with. Use milligrams on small tiles
> How could Si give a violent reaction? Any reference for that?
>
> Sorry if the tone of my mail seems harsh. It is not my intention.
>
> Unfortunately, I have very few time to devote to pottery as it
> is not my work.
> Anne
>
> --
>
> Anne Possoz
> http://slpc7.epfl.ch/~possoz
> ch. de Bonne-Esperance 17
> CH 1006 Lausanne SUISSE
> E-Mail : Anne.Possoz@epfl.ch
> Tel+fax+rep : (41/21) 728.53.45
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
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