Robert Harris on thu 12 aug 10
On Thu, Aug 12, 2010 at 10:57 PM, Lee Love wrote:
>
> =3DA0It was the salt fuming that contain contained the lead. =3DA0They mi=
xed
> powdered lead and salt. =3DA0The lead "vapor" caused the early demise of
> German potters.
>
Yes, I'm sure. In the UK, I think the problem was white lead oxide (or
perhaps red lead), which also killed the pottery workers at an early
age. From what I've read the development of Bristol glazes was a
direct response to the early deaths of factory workers by lead
poisoning. Obviously someone then came up with using lead bisilicate
which is much safer, but I believe that was much later.
(Can you believe that the Elizabethans used white lead to powder their
faces - that really did a number on them!).
Edouard Bastarache on thu 12 aug 10
Hello Vince and all,
years ago to answer a question asked on Clayart I contacted
Bernd Pfannkuche
a german international ceramics consultant, author of "Ceramics and=3D20
Earths/Keramik und Erden-Dictionary/W=3DF6rterbuch" and "Handbuch der=3D20
Keramikbrenn=3DF6fen".
Now editor of Neue Keramik of Berlin, about the health issues of these=3D20
techniques of firing : salt and soda, he told me, especially in the case =
=3D
of=3D20
salt, that this process had been used in Germany for centuries without an=
=3D
y=3D20
deleterious effect.
Gis,
Edouard Bastarache
Spertesperantisto
Sorel-Tracy
Quebec
http://www.flickr.com/photos/30058682@N00/
http://edouardbastarache.blogspot.com/
http://blogsalbertbastarache.blogspot.com/
http://cerampeintures.blogspot.com/
http://www.facebook.com/edouard.bastarache
----- Original Message -----=3D20
From: "Vince Pitelka"
To:
Sent: Thursday, August 12, 2010 3:12 PM
Subject: Re: soda and environment
> In response to David Beumee's post below, the safety GOOD guy, Jeff Zam=
=3D
ek
> (in comparison to the wacko safety Nazi who writes for a popular=3D20
> magazine),
> has done the research, and has shown that the worst thing produced by a=
=3D
=3D20
> soda
> kiln is the slow corrosion of ferrous surfaces in the immediate area. J=
=3D
eff
> can be reached via his website at www.jeffzamek.com. Do not let parano=
=3D
id
> local officials stop you from building a soda kiln. Jeff can probably=3D=
20
> help.
>
> - Vince
>
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Tech University
> vpitelka@dtccom.net; wpitelka@tntech.edu
> http://iweb.tntech.edu/wpitelka
>
>
>
> -----Original Message-----
> From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of David Beum=
=3D
ee
> Sent: Thursday, August 12, 2010 10:03 AM
> To: Clayart@LSV.CERAMICS.ORG
> Subject: soda and environment
>
> I'm very interested in building and firing a small soda kiln. The city
> official who I contacted for permission to build is not convinced of th=
=3D
e
> evidence of environmental safety that I presented, namely Ruthann=3D20
> Tudball's
> quotes from Gail Nichols book "Soda, Clay, and Fire." That the Pollutio=
=3D
n
> Inspectorate in the UK deemed that effluent from studio potters' sodium
> vapor kilns "trivial and insignificant" in relation to other forms of
> pollution (Tudball 1995) is not convincing enough to our city building
> inspector. He wants updated assurance of the environmental safety of
> injecting sodium bicarb into a kiln. Ruthann Tudball argues that any=3D20
> sodium
> hydroxide vapor emitted from the chimney would convert back to to soda=3D=
20
> ash,
> (sodium carbonate), and that the environmental effects from a studio
> potter's kiln would be minimal, but our city inspector argues that soda=
=3D
=3D20
> ash
> is caustic and therefore unsafe. When I made a comparison between the
> pollution produced by an occasionally fired 16 cu. ft. soda kiln and th=
=3D
e
> pollution produced by driving a car for a year, or to that of a jumbo j=
=3D
et
> taking off and landing, that argument got nowhere with him. Does anyone=
=3D
=3D20
> know
> of evidence of environmental safety of firing a soda kiln that relies o=
=3D
n
> research done in the US since 1995?
>
> David Beumee
> Porcelain by David Beumee
> Lafayette, CO
>=3D20
Lee Love on thu 12 aug 10
On Thu, Aug 12, 2010 at 4:50 PM, Edouard Bastarache wr=
=3D
ote:
> Now editor of Neue Keramik of Berlin, about the health issues of these
> techniques of firing : salt and soda, he told me, especially in the case =
=3D
of
> salt, that this process had been used in Germany for centuries without an=
=3D
y
> deleterious effect.
This is another case where, like copper, modern vapor firing in
itself, in not hazardous. Originally, copper was found to make lead
glazes release lead more easily. In the early days, salt was
mixed with lead and put into the kilns. It was the lead that caused
harm to the potters, not salt.
It is in the book about Wildenhain. The church records for potters
found that they had a short life expectancy. But their methods have
nothing to do with todays soda or salt firing.
--
=3DA0Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
Robert Harris on thu 12 aug 10
Lead poisoning has been known about for quite sometime, which lead to
the development of Bristol Glazes in the 19th C in which the lead was
replaced by zinc.
Having come from the UK I have always found it interesting that zinc
oxide is still much more commonly used as an adjunct flux in the UK,
whereas over here in the US boron is much more commonly used - whereas
it's rarely used in the UK. Presumably this is because there really
aren't any boron deposits (especially not insoluble ones) in the UK.
Just looking at Emmanuel Cooper's books seems to back this anecdotal
evidence up.
In addition, in the UK most electric firing (again very anecdotally)
seems to be done to 1260-1270C which is more like cone 8-9 (depending
on rate of climb) - which is neither Cone 6 or Cone 10 - which seem to
be most common here in the US.
It's interesting how pervasive these sort of cultural artifacts seem
to be - and how influenced by our own teachers we are - even when we
think we're being different.
For those Canadians and Australians out there (who sometimes seem to
have adopted British practices, and sometime US practices) have you
noticed anything similar and what do you do?
Robert
Robert
Robert Harris on thu 12 aug 10
Oh, I should add that I realise that Zinc Oxide can only be used in
oxidation. The use of electric kilns in the UK also seems to be more
pervasive amongst "professional" potters. This may be due to clean air
acts (which got rid of London pea-soup smogs so don't knock 'em too
much) or it may be due to the cost of firing.
Again though, reduction and wood firing aren't nearly as pervasive in
the UK as they are here (John Leach being a notable exception).
Another cultural (or perhaps legal?) artifact.
Robert
On Thu, Aug 12, 2010 at 8:59 PM, Robert Harris wr=
ote:
> Lead poisoning has been known about for quite sometime, which lead to
> the development of Bristol Glazes in the 19th C in which the lead was
> replaced by zinc.
>
> Having come from the UK I have always found it interesting that zinc
> oxide is still much more commonly used as an adjunct flux in the UK,
> whereas over here in the US boron is much more commonly used - whereas
> it's rarely used in the UK. Presumably this is because there really
> aren't any boron deposits (especially not insoluble ones) in the UK.
>
> Just looking at Emmanuel Cooper's books seems to back this anecdotal
> evidence up.
>
> In addition, in the UK most electric firing (again very anecdotally)
> seems to be done to 1260-1270C which is more like cone 8-9 (depending
> on rate of climb) - which is neither Cone 6 or Cone 10 - which seem to
> be most common here in the US.
>
> It's interesting how pervasive these sort of cultural artifacts seem
> to be - and how influenced by our own teachers we are - even when we
> think we're being different.
>
> For those Canadians and Australians out there (who sometimes seem to
> have adopted British practices, and sometime US practices) have you
> noticed anything similar and what do you do?
>
> Robert
>
> Robert
>
--
----------------------------------------------------------
Lee Love on thu 12 aug 10
On Thu, Aug 12, 2010 at 7:59 PM, Robert Harris wr=
=3D
ote:
> Lead poisoning has been known about for quite sometime, which lead to
> the development of Bristol Glazes in the 19th C in which the lead was
> replaced by zinc.
It was the salt fuming that contain contained the lead. They mixed
powdered lead and salt. The lead "vapor" caused the early demise of
German potters.
--
=3DA0Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
Lee Love on fri 13 aug 10
I use a fluxing material in my soda fire mixture. The Germans put
lead in their salt, I put whiting in my mix. Someone suggested
putting wood ash in with the soda ash and bicarbonate. Haven't tried
that yet.
--
=3DA0Lee, a Mashiko potter in Minneapolis
http://mingeisota.blogspot.com/
=3D93Observe the wonders as they occur around you. Don't claim them. Feel
the artistry moving through and be silent.=3D94 --Rumi
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