Paul Borian on wed 17 mar 10
I bisque to cone 04 in electric kilns and as they get close to top temp,
perhaps an hour or two away from it, the kiln shed starts to smell
really bad. It's not just a smell, but more like a heavy fog that
basically I can't even breathe without choking. That's if I have to
stand really close to the kiln for a moment or two - usually at that
point I stay out of there.
Thus, it is something you can feel, rather than just smell...
=3D20
Anyway, the plastics in my clay body are EPK, foundry hill, hawthorne
bond and goldart. I suspect the stuff burning off is from the latter two
(one or both of them) and I would like to know just what it is. Do most
clay bodies smell like this during bisque firings?
My best guess is that it is sulphor from the goldart - but I have also
heard that clay does not have the same sulphor content it used to a long
time ago
=3D20
Does anyone else have a clay body that does this? ever figure out what
it is?
=3D20
Thanks,
Paul
phil on wed 17 mar 10
Hi Paul,
Don't breathe any of it...
Vent the Room well...to the out of Doors...drawing fresh Air 'in', and, sta=
y
out of the area during Bisque-times.
All kinds of nastys there in that fume and 'fog'...
Hydrofluoric Acid Gas, likely among them...( are the Windows 'frosted'?
Lol...) but worse things too.
Not so good...
'Choking' is one of Nature's ways of saying "Steer Clear of those Shores!"
Far as what causes it...eeeeeeesh, we need an Organic Chemist to do justice=
.
Messy...
Phil
Lv
----- Original Message -----
From: "Paul Borian"
I bisque to cone 04 in electric kilns and as they get close to top temp,
perhaps an hour or two away from it, the kiln shed starts to smell
really bad. It's not just a smell, but more like a heavy fog that
basically I can't even breathe without choking. That's if I have to
stand really close to the kiln for a moment or two - usually at that
point I stay out of there.
Thus, it is something you can feel, rather than just smell...
Anyway, the plastics in my clay body are EPK, foundry hill, hawthorne
bond and goldart. I suspect the stuff burning off is from the latter two
(one or both of them) and I would like to know just what it is. Do most
clay bodies smell like this during bisque firings?
My best guess is that it is sulphor from the goldart - but I have also
heard that clay does not have the same sulphor content it used to a long
time ago
Does anyone else have a clay body that does this? ever figure out what
it is?
Thanks,
Paul
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11:33:00
Linda White on wed 17 mar 10
On Mar 17, 2010, at 1:12 AM, Paul Borian wrote:
> I bisque to cone 04 in electric kilns and as they get close to top
> temp,
> perhaps an hour or two away from it, the kiln shed starts to smell
> really bad. It's not just a smell, but more like a heavy fog that
> basically I can't even breathe without choking. That's if I have to
> stand really close to the kiln for a moment or two - usually at that
> point I stay out of there.
>
> My best guess is that it is sulphor from the goldart - but I have also
> heard that clay does not have the same sulphor content it used to a
> long
> time ago
I did a bisque to 07 last night and it was intense! VERY BAD smell
that set off my asthma big time and a very heavy fog. I don't use
goldart--I use Hawthorne Bond, Foundry Hill Creme, EPK, Old Mine #4
and Red Art. Also nepheline syenite, silica, talc, epsom salt and
bentonite. It would be good to know what it is.
Linda White
LickHaven Pottery
Dushore PA
jonathan byler on wed 17 mar 10
Hydrogen sulfide gas. bad news. irritates the lungs, eyes, and
more. rusts everything in site as it mixes with moisture in the air
to make sulfuric acid. you need venting or to use some other claybody
with less sulfur in it. actually, strike that, you need venting
regardless of what claybody you use.
On Mar 17, 2010, at 12:08 PM, Linda White wrote:
> On Mar 17, 2010, at 1:12 AM, Paul Borian wrote:
>
>> I bisque to cone 04 in electric kilns and as they get close to top
>> temp,
>> perhaps an hour or two away from it, the kiln shed starts to smell
>> really bad. It's not just a smell, but more like a heavy fog that
>> basically I can't even breathe without choking. That's if I have to
>> stand really close to the kiln for a moment or two - usually at that
>> point I stay out of there.
>>
>> My best guess is that it is sulphor from the goldart - but I have
>> also
>> heard that clay does not have the same sulphor content it used to a
>> long
>> time ago
>
> I did a bisque to 07 last night and it was intense! VERY BAD smell
> that set off my asthma big time and a very heavy fog. I don't use
> goldart--I use Hawthorne Bond, Foundry Hill Creme, EPK, Old Mine #4
> and Red Art. Also nepheline syenite, silica, talc, epsom salt and
> bentonite. It would be good to know what it is.
>
> Linda White
> LickHaven Pottery
> Dushore PA
phil on wed 17 mar 10
Hi Jonathan,
Hydrogen Sulfide...
Is that not the Calling Card of Beelzelbub hisself?
Hydrogen Cyanic Acid is another charmer of course...
"Oh Honey! Is that your famous Home Made Marzipan I smell???"
"Yes dear...it's almost ready!...you DID update those Policies, yes?"
"Of course darling..!"
"Plunk"...
Lol...
----- Original Message -----
From: "jonathan byler"
> Hydrogen sulfide gas. bad news. irritates the lungs, eyes, and
> more. rusts everything in site as it mixes with moisture in the air
> to make sulfuric acid. you need venting or to use some other claybody
> with less sulfur in it. actually, strike that, you need venting
> regardless of what claybody you use.
Linda White on wed 17 mar 10
On Mar 17, 2010, at 3:23 PM, jonathan byler wrote:
> Hydrogen sulfide gas. bad news. irritates the lungs, eyes, and
> more. rusts everything in site as it mixes with moisture in the air
> to make sulfuric acid. you need venting or to use some other claybody
> with less sulfur in it. actually, strike that, you need venting
> regardless of what claybody you use.
>
How do I find out which clays have sulfur in them? I know Goldart
does, and that's one reason I don't use it. And, I do have venting.
Linda White
LickHaven Pottery
Dushore PA
jonathan byler on wed 17 mar 10
if you smell it, you need more venting. or better venting. the kiln
vents that use the little bit of dryer vent seem totally inadequate in
my experience. proper vent hood over the top of the kiln seems to be
the only way to keep the kiln room free of stink and poison.
the worst about this stuff is that it reacts with the chrome in the
stainless steel used to hold the kiln together and EATS up the
bricks. they can withstand a lot, even the sulfur gas on its own, but
not whatever is formed by the chrome and the sulfur when they meet.
Not sure how to tell which clays have sulfur in them, but it seems a
very undesirable trait for clay to have. from what I can tell it is
in the form of iron sulfide? I don't know if it is in other forms in
the clay, too, but I have never seen it in low iron bodies like
porcelain. not that all clay with iron in it has sulfur, but perhaps
all clay that has sulfur also has iron? I would be interested to hear
what one of the authorities like RR or Ivor or the neon cat has to say
about this.
On Mar 17, 2010, at 6:47 PM, Linda White wrote:
>>
>
>
> How do I find out which clays have sulfur in them? I know Goldart
> does, and that's one reason I don't use it. And, I do have venting.
>
> Linda White
> LickHaven Pottery
> Dushore PA
Monica Wright on wed 17 mar 10
I would think that "most" clays have some sulfur in them.=3DA0 Goldart just=
h=3D
as a bunch.=3DA0 Absolutely nothing wrong as long as you vent properly -man=
y =3D
ways to do that.=3DA0 Nothing like a little sulfuric acid to wake you up du=
ri=3D
ng a firing.=3DA0 Yuck!=3D0A=3D0A=3D0A=3D0A=3D0A___________________________=
_____=3D0AFrom=3D
: Linda White =3D0ATo: Clayart@LSV.CERAMICS.ORG=3D0ASent:=
Wed=3D
, March 17, 2010 6:47:14 PM=3D0ASubject: Re: bisque firing smells really ba=
d =3D
- what causes it?=3D0A=3D0AOn Mar 17, 2010, at 3:23 PM, jonathan byler wrot=
e:=3D
=3D0A=3D0A> Hydrogen sulfide gas.=3DA0 bad news.=3DA0 irritates the lungs, =
eyes, an=3D
d=3D0A> more.=3DA0 rusts everything in site as it mixes with moisture in th=
e ai=3D
r=3D0A> to make sulfuric acid.=3DA0 you need venting or to use some other c=
layb=3D
ody=3D0A> with less sulfur in it.=3DA0 actually, strike that, you need vent=
ing=3D
=3D0A> regardless of what claybody you use.=3D0A>=3D0A=3D0A=3D0AHow do I fi=
nd out whi=3D
ch clays have sulfur in them? I know Goldart=3D0Adoes, and that's one reaso=
n =3D
I don't use it. And, I do have venting.=3D0A=3D0ALinda White=3D0ALickHaven =
Potter=3D
y=3D0ADushore PA=3D0A
Vince Pitelka on wed 17 mar 10
Linda White wrote:
"How do I find out which clays have sulfur in them? I know Goldart does, an=
d
that's one reason I don't use it. And, I do have venting."
Hi Linda -
There is always going to be some sulfur in your clays. You cannot avoid it=
,
and there is no reason to avoid using clays with sulfur in them. Just don'=
t
breath the fumes. If you have good venting, then it is not a problem.
Sulfur dioxide and hydrogen sulfide are serious irritants, but they are not
cumulative, and the quantities produced by a kiln are just irritants, unles=
s
you have special conditions that might cause a more severe reactions.
That's certainly something to watch out for, but just like sensitivity to
ash glazes, it is the responsibility of people with special health
conditions to take appropriate precautions.
You do not want to be breathing any dusts or fumes under any circumstances.
My only first-had experience of the effects of sulfur dioxide and hydrogen
sulfide occurred at a university where I was teaching a couple of workshops
and doing a week-long visiting artist gig. They promised me a place to wor=
k
for the week, and it turned out to be in the middle of the room where all
the electric kilns were located. At the time they did not have any
ventilation. This was a long time ago, and I really didn't know better at
the time. I worked in there all week. At the end of the week, some friend=
s
of mine in the area threw a birthday party for me. They all brought their
instruments and we had a music session, but my throat was so sore and my
voice so hoarse that I couldn't sing. That was the extent of the effects,
but it taught me a lesson. Breathing those fumes was a stupid thing to do.
I should have known better even then.
But like I said, if you have proper ventilation, this is a non-issue.
- Vince
Vince Pitelka
Appalachian Center for Craft
Tennessee Tech University
vpitelka@dtccom.net; wpitelka@tntech.edu
http://iweb.tntech.edu/wpitelka
ivor & olive lewis on thu 18 mar 10
Hydrogen Sulphide has a high degree of toxicity. It also has an anaesthetic
action on the sense of aroma so that an it cannot be sensed as it approache=
s
a toxic concentration, which Durrant gives as 0.1 percent. Plumbers who hav=
e
to deal with the disposal of farm waste have been known to fatally succumb
to it when working in confined unventilated spaces of septic tanks..
If Hydrogen sulphide is present in the atmosphere it can be detected with
adsorbent paper soaked in one of several soluble metallic salts, eg Copper
sulphate, Ferrous nitrate or Potassium chromate. If a clay is suspected of
containing Sulphides, Hydrogen sulphide would be generated if a sample of
clay were treated by adding dilute Hydrochloric acid to the powder.
Metallic sulphides decompose when heated strongly and form oxides in an
oxidising atmosphere discharging Sulphur dioxide, a gas which dissolves in
water to form Sulphurous Acid..From memory, a catalyst is necessary to
generate Sulphur trioxide and hence, Sulphuric acid.
Regards,
Ivor Lewis,
Redhill,
South Australia
ivor & olive lewis on thu 18 mar 10
Dear Linda White,
You ask...t
does, and that's one reason I don't use it. And, I do have venting.>
It would be unusual for a clay to contain elemental Sulphur unless it
originated in a volcanic region.
However, Iron Sulphide, Pyrites is often found in sediments. The presence o=
f
Pyrites or of other metallic sulphide minerals could be established with
simple spot tests. If you are wondering about the cloy you buy, ask for a
data sheet.
I have some fire bricks whose clay was originally contaminated with some
form of sulphide mineral. I know this because they contain dark blotches of
Iron oxide.
Regards,
Ivor Lewis,
Redhill,
South Australia
ivor & olive lewis on fri 19 mar 10
Dear Jonathan Byler,
In answer to your suggestion I suppose a good way to find out about any
native clay would be to extract the denser mineral fractions which include
the sulphide group.
This is done by repeatedly washing a suspension of suspect clay in a clean
grease free Gold Pan and retaining the heavy and denser fraction. It would
be unusual for a native clay not to leave behind a residue which can be
examined in several ways.
A strong hand lens will reveal colours and minute crystals whose colour and
shape can be informative. A strong magnet will discriminate the oxides of
Iron. A few drops of weak Hydrochloric acid will release Hydrogen sulphide,
enough to experience the rotten egg smell but insufficient to be harmful.
Pyrites and Chalcopyrites will dissolve in that acid, Gold will not.
Even an clean grease free aluminium fry pan is good enough to test clay in
this way.
Porcelain, by definition, is compounded from purified ingredients that have
been treated to remove all the accessory minerals from the original mine ru=
n
feedstock.
But native clay, including the Terra Cotta versions, can give a rich deposi=
t
of interesting minerals when levigated.
The Elementary Skills of Prospecting might profitably be introduced into th=
e
curriculum of courses for would be potters and ceramic artists.
Ivor Lewis,
Redhill,
South Australia
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