JoaGrant@aol.com on sat 13 apr 96
Carbon plus oxygen can do combustion to produce carbon monoxide, a poisonous
gas.
Richard J.Mahaffey on thu 18 apr 96
Hi Lowell,
I used graphite pencil drawings in saggar firings years ago and where they
were under charcoal they stayed and lo and behold, you could erase or smudge
them. The other area usually was gone. I would certainly try the Graphite
in the saggar.
As to the fire fighters succumbing to fumes at the crash site, I would suspect
the resins that hold the graphite fibers or cloth into the desired shape are
to blame. That said I would still take precautions when firing and certainly
unloading. I have had the fine dust cause some nasty coughing till I started
wearing a dust mask and ventilating the area. One of my teachers said: "you
should always treat ceramic materials like they are toxic".
Good luck and do let us know how it goes.
Rick Mahaffey
JCooper on fri 21 jan 00
------------------
graph=95te n.a very common mineral, soft native carbon, occurring in
black to dark-gray foliated masses, with metallic luster and greasy
feel: used for pencil leads, as a lubricant, and for making crucibles
and other refractories=3B plumbago=3B black lead. =5B1790=961800=3B =3C G =
Graphit =3C
Gk gr=E1ph ( ein) to write, draw + G -it -ITE1=5D=97 gra=95phit=95ic (gr=83
fit=82ik) adj.
Copyright =A9 1966-1994 by Random House Inc., All Rights Reserved.
Marcia Selsor on fri 21 jan 00
I have used graphite as a surface finish on some sculpture. I use a
fixatif to keep it on. I think graphite is more carbon than lead but I
don't lick it.
Marcia in Montana
Roger Bourland wrote:
>
> ----------------------------Original message----------------------------
> Darndest urinals I ever saw were in a church in western Nebraska where I
> gave a speech. To save space, I presume, the urinals were arranged at a 90'
> angle to one another, so that, unless one was alone, there was always
> someone facing you - at right angles. John Wayne once said that the most
> difficult problem of being a celebrity came when the guy standing next to
> you at a urinal turned and said: "Say, aren't you John Wayne?" The 90 '
> angle would solve that problem. But then who wants to use a urinal looking
> at someone? Weirdest ones were at Maddona Inn in San Luis Obispo, Ca. Good
> Lord! A whole tourist buss passed through there the one time I visited. But
> I ramble.
>
> There was an article in CM this month about using graphite as a surface
> agent for ^012 pots. Looks great and easy too. But if one were to make a
> bean pot fired with graphite surface, would there be a toxicity problem?
> Graphite is, after all, also called "black lead." I used to lick my lead
> pencils in grade school all the time. Maybe that's what is wrong.
>
> Best,
>
> Roger
--
Marcia Selsor
selsor@imt.net
http://www.imt.net/~mjbmls
http://www.imt.net/~mjbmls/spain99.html
http://www.silverhawk.com/ex99/selsor/welcome.html
Norman van der Sluys on sun 23 jan 00
Graphite is a form of carbon and as far as I know (I'm no toxicologist) it is
non-toxic. The survival of generations of pencil chewers attests to this.
Norman van der Sluys
Jackpottery
http://jackpottery.tripod.com/
Marcia Selsor wrote:
> ----------------------------Original message----------------------------
> I have used graphite as a surface finish on some sculpture. I use a
> fixatif to keep it on. I think graphite is more carbon than lead but I
> don't lick it.
> Marcia in Montana
>
> Roger Bourland wrote:
> >
> > ----------------------------Original message----------------------------
> > Darndest urinals I ever saw were in a church in western Nebraska where I
> > gave a speech. To save space, I presume, the urinals were arranged at a 90'
> > angle to one another, so that, unless one was alone, there was always
> > someone facing you - at right angles. John Wayne once said that the most
> > difficult problem of being a celebrity came when the guy standing next to
> > you at a urinal turned and said: "Say, aren't you John Wayne?" The 90 '
> > angle would solve that problem. But then who wants to use a urinal looking
> > at someone? Weirdest ones were at Maddona Inn in San Luis Obispo, Ca. Good
> > Lord! A whole tourist buss passed through there the one time I visited. But
> > I ramble.
> >
> > There was an article in CM this month about using graphite as a surface
> > agent for ^012 pots. Looks great and easy too. But if one were to make a
> > bean pot fired with graphite surface, would there be a toxicity problem?
> > Graphite is, after all, also called "black lead." I used to lick my lead
> > pencils in grade school all the time. Maybe that's what is wrong.
> >
> > Best,
> >
> > Roger
>
> --
> Marcia Selsor
> selsor@imt.net
> http://www.imt.net/~mjbmls
> http://www.imt.net/~mjbmls/spain99.html
> http://www.silverhawk.com/ex99/selsor/welcome.html
Communications Museum on mon 24 jan 00
My email retrieval has been erratic, so apologies if this has been
covered. Graphite is carbon, all carbon, 100% carbon, in fact it's
chemical formula is C. Lead is lead, all lead, Pb. Two totally different
molecules. Graphite is, in fact, the same as diamond, with their only
difference being graphites weaker ionic bonds. That's the
geology/chemistry side. I know little biology, but am fairly certain
that carbon, in the amounts referred to here, would be almost wholly
inert. it is bonded in such a way that it will not readily bond to
anything else without a significant change in energy/environment. I
would use it, and not worry, unless you're planning on eating it as a
snack.
Marcia Selsor wrote:
> I have used graphite as a surface finish on some sculpture. I use a
> fixatif to keep it on. I think graphite is more carbon than lead but I
> don't lick it.
> Marcia in Montana
I.Lewis on wed 26 jan 00
------------------
Sorry to disagree with Troy Judd about the purity of coal. Coal is not a =
pure
form of elemental Carbon. All the coal I have burned leaves huge quantities =
of
ash. Even anthracite, which has the highest proportion of carbon, close to =
one
hundred percent leaves an ash when burned. Coal ash is produced in mega ton
quantities by coal burning power stations. Disposal of this residue is a =
major
environmental problem. People who fire electric may already be aware of =
this.
Diamond and Graphite burn without residue other than carbon dioxide
Troy Judd on thu 27 jan 00
Ouch. But really, my point was that the carbon in coal burns to produce
carbon dioxide and as you said diamond and graphite also burn to form carbon
dioxide. What I was surprised at was the idea of using graphite in a kiln.
I had assumed it would burn off at these temperatures. Is the crystaline
structure enough to raise the spontaneous combustion point of graphite
beyond this? What temperature does graphite burn at? I'm not sure tho old
CNC will have the info but I plan to loo it up. I'd just stick a pencil in
the gas flame of my range, but it's disconnected right now while I put tile
down in the kitchen.
Troy Judd
----------------------------Original message----------------------------
------------------
Sorry to disagree with Troy Judd about the purity of coal. Coal is not a
pure
form of elemental Carbon. All the coal I have burned leaves huge quantities
of
ash. Even anthracite, which has the highest proportion of carbon, close to
one
hundred percent leaves an ash when burned. Coal ash is produced in mega ton
quantities by coal burning power stations. Disposal of this residue is a
major
environmental problem. People who fire electric may already be aware of
this.
Diamond and Graphite burn without residue other than carbon dioxide
mary simmons on thu 27 jan 00
there is NO CO2 in graphite or diamond, ever.
At 04:42 PM 1/26/00 EST, you wrote:
>----------------------------Original message----------------------------
>------------------
>Sorry to disagree with Troy Judd about the purity of coal. Coal is not a pure
>form of elemental Carbon. All the coal I have burned leaves huge
quantities of
>ash. Even anthracite, which has the highest proportion of carbon, close to
one
>hundred percent leaves an ash when burned. Coal ash is produced in mega ton
>quantities by coal burning power stations. Disposal of this residue is a
major
>environmental problem. People who fire electric may already be aware of this.
>
>Diamond and Graphite burn without residue other than carbon dioxide
>
Carolyn Nygren Curran on fri 28 jan 00
to Troy...Am I missing something? I imagine you are not referring to me
when you mention the "old CNC". Now my nickname is CNC, and my DBA is CNC
Pottery. I am also going to start collecting social security this year
when I turn 62, and I'm not insulted to be called old, although I would
dispute the term. At any rate, I still don't know what the CNC
is...computer something or other, I think. Would you elucidate for me? I
get enough confusion with CMC in the glaze room, and I'd like to know what
the other CNC is so I can be in the know. TIA from CNC, aka Carolyn
Nygren Curran
ferenc jakab on fri 28 jan 00
Troy,
Below is an extract from the BK Periodic Table software's element
information for Carbon. The melting point is approximately 9000 Deg F.
Feri
6 - C - Carbon
Atomic Weight: 12.011 g/mol
Oxidation States: +/-4, 2
Boiling Point: 5100* K
Melting Point: 3825* K
Density: 2.26 g/cm3
Electron Configuration: 1s2,2s2,p2
Acid/Base Properties: Acidic
Crystal Structure: Hexagonal
Electronegativity: 2.55
Heat of Vaporization: 715 kJ/mol
Heat of Fusion: --
Electrical Conductivity: 0.07 10^6omg-9cm-9
Thermal Conductivity: 80-230 Wm-9K-9 (at 300 K)
Specific Heat Capacity: 0.709 Jg-9K-9 (at 300 K)
First Ionization Potential: 11.260
Atomic Volume: 5.30 cm3/mol
Atomic Radius: 0.91 E
Covalent Radius: 0.77 E
Synthetic: No
Michael Banks on fri 28 jan 00
Troy,
Some explanation of structural chemistry is required to answer your
question:
Graphite and diamond are two of the polymorphs (different crystalline atomic
arrangements) of carbon. In graphite the carbon atoms are arranged in
hexagonal sheets, only one atom thick. In the sheets the carbons are
powerfully bonded to each other by sharing valence electrons (covalent
bonds) in only two dimensions. Between the sheets, the layers are only
weakly tacked together by feeble attraction of slightly dissimilar charges
(van der Waals bonds). This weak glue between the sheets gives rise to
graphite's slippery nature, as the sheets slide easily over each other.
Similar structures occur in other slippery minerals e.g. molybdenite and
clay minerals.
In diamond, the carbons are covalently bonded in three dimensions in a cubic
lattice of tetrahedral arrangement. There are few planes of weakness in this
structure (though they do occur, allowing diamonds to be cleaved by expert
gem cutters). A surface coated with diamond grit is far from slippery
though.
There are known to be many other carbon polymorphs as well as graphite and
diamond, with varying stability, such as spherical ball arrangements, e.g.
buckminsterfullerene (sp?), "bucky balls".
Minerals bonded in 3D are more stable than those bonded in 2D. Diamond can
be exposed to higher temperatures in an oxygen atmosphere than graphite.
Diamonds rate of oxidation is slower. This can translate into a higher
ignition temperature. Amorphous carbon, such as carbon black used in tires,
are the least stable form of carbon and succumb to attack by oxygen at a
much higher rate than graphite.
Many minerals exhibit varying stability to heat due to varying stability of
their atomic internal bonds. Amorphous silica (disordered structure) for
example, dissolves in molten glazes much faster than quartz. Industrial
alumina (disordered), faster than corundum (crystalline alumina).
Michael Banks,
Nelson,
New Zealand
> ----------------------------Original message----------------------------
> Ouch. But really, my point was that the carbon in coal burns to produce
> carbon dioxide and as you said diamond and graphite also burn to form
carbon
> dioxide. What I was surprised at was the idea of using graphite in a
kiln.
> I had assumed it would burn off at these temperatures. Is the crystaline
> structure enough to raise the spontaneous combustion point of graphite
> beyond this? What temperature does graphite burn at? I'm not sure tho
old
> CNC will have the info but I plan to loo it up. I'd just stick a pencil
in
> the gas flame of my range, but it's disconnected right now while I put
tile
> down in the kitchen.
>
> Troy Judd
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