Kurt Wild on fri 4 may 01
Joseph Herbert wrote:
>Following that logic, lye would provide fewer possible
>combinations than washing soda and so might be more
>effective at supplying sodium without the problem of the
>accompanying chlorine gas.
I question the notion that salt firings emit chlorine gas It is my
understanding that the by product is hydrochloric acid mist/fumes - not
chlorine gas.
Kurt
vince pitelka on fri 4 may 01
> I question the notion that salt firings emit chlorine gas It is my
> understanding that the by product is hydrochloric acid mist/fumes - no=
t
> chlorine gas.
Kurt -
That is correct. Salt firings produce hydrochloric acid fumes, which mak=
e
metals corrode like crazy, but are benign to humans.
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
vince pitelka on sat 5 may 01
> While that might not be the most dangerous situation we encounter as
> potters, that is NOT benign! No one should ever walk through or breathe
the
> cloud coming off a salt kiln for several minutes after salting. Stay well
> upwind.
Sorry John, but unless a potter is breathing the fumes straight from the
stack or ports, there is no danger at all. I have been around a great deal
of salt firings, and the fumes rise straight up from the ports and stack,
and it would be very difficult to breath those vapors under any
circumstance. I agree that no one should be sucking those fumes, but we
need to maintain a realistic perspective. As you probably know, the
historical record shows that in salt-firing factory situations the workers
used to breath the salt fumes eminating from the kiln in order to open
clogged sinuses and nasal passages, with no record of ill effect at all.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://www.craftcenter.tntech.edu/
John Hesselberth on sat 5 may 01
> From: vince pitelka
>
> Salt firings produce hydrochloric acid fumes, which make
> metals corrode like crazy, but are benign to humans.
Vince,
The following is a quote from Sax "Dangerous Properties of Industrial
Materials".
Hydrochloric acid: Hydrochloric acid is an irritant to the mucous membra=
nes
of the eyes and respiratory tract, and a concentration of 35 ppm causes
irritation of the throat after short exposure. Concentrations of 50-100 =
are
tolerable for 1 hour. More severe exposures result in pulmonary endema, =
and
often laryngeal spasm. Concentrations of 1000-2000 ppm are dangerous eve=
n
for brief exposures.
While that might not be the most dangerous situation we encounter as
potters, that is NOT benign! No one should ever walk through or breathe =
the
cloud coming off a salt kiln for several minutes after salting. Stay wel=
l
upwind.
Regards,
John
Web site: http://www.frogpondpottery.com Email: john@frogpondpottery.co=
m
"The life so short, the craft so long to learn." Chaucer's translation of
Hippocrates, 5th cent. B.C.
Charles on sun 6 may 01
We are having a lot of back and forth on this one...has anyone done any
emissions testing? If so, what specifically does the data say? I have heard
so many people arguing on this subject and no one has ever cited studies.
-C
>
>
iandol on sun 6 may 01
Dear John,
Thank you for reinforcing that safety message.
I would not participate in a salt firing without wearing a respirator =
with acid adsorbent and particulate collecting cartridges.
There is no evidence that Hydrochloric acid is a primary product but is =
can form when some of the solid particles which discharge from the stack =
mix with water. Which is what they would do in the nasal and bronchial =
tracts.
Best regards,
Ivor
John Hesselberth on sun 6 may 01
Sorry also Vince, but I think your position is less than responsible here.
I have been around salt firings on a still day when the cloud settled down
right on the kiln and immediately surrounding area. Just because factory
workers used to breathe the fumes to clear their sinuses hardly proves that
it is a safe thing to do. I know people that smoke and still live to be 100
too. I'll let Sax be my guide on what safe exposures are vs. "but he did it
and didn't get hurt" type stories.
Go ahead and breathe them if you like, but I don't think teaching students
that these fumes are "benign" is a good thing to do.
John
Web site: http://www.frogpondpottery.com Email: john@frogpondpottery.com
"The life so short, the craft so long to learn." Chaucer's translation of
Hippocrates, 5th cent. B.C.
> From: vince pitelka
>
> Sorry John, but unless a potter is breathing the fumes straight from the
> stack or ports, there is no danger at all. I have been around a great deal
> of salt firings, and the fumes rise straight up from the ports and stack,
> and it would be very difficult to breath those vapors under any
> circumstance. I agree that no one should be sucking those fumes, but we
> need to maintain a realistic perspective. As you probably know, the
> historical record shows that in salt-firing factory situations the workers
> used to breath the salt fumes eminating from the kiln in order to open
> clogged sinuses and nasal passages, with no record of ill effect at all.
Edouard Bastarache on sun 6 may 01
Well guys,
it is a matter of level of exposure.
"1 shot of gin a day has never killed anyone,
but 40 may in the long run."
If salt-firing was so hazardous, Germany would not
have had enough soldiers to fight 2 world wars in
Europe.
German potters (factory and studio) have been using
this technique for many centuries without deleterious
effects on their health. There is nothing in NIOSHTIC &
OSHLINE database described pertaining to this
work situation.
In the Westerwald, the heart of the saltglaze
production of Germany, since hundreds of years until today
they produce and you can buy saltglazed dinnerwares.
For a long time this technique was used to
glaze drainage pipes as well as equipment and
containers for the chemical industry, so far as a high durability
against abrasion or chemical attack is requested.
Later,
Edouard Bastarache
Irr=E9ductible Qu=E9becois
Sorel-Tracy
Dans / In "La Belle Province"
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
----- Message d'origine -----
De : John Hesselberth
=C0 :
Envoy=E9 : 6 mai, 2001 08:35
Objet : Re: Lye & chlorine gas
> Sorry also Vince, but I think your position is less than responsible he=
re.
> I have been around salt firings on a still day when the cloud settled d=
own
> right on the kiln and immediately surrounding area. Just because facto=
ry
> workers used to breathe the fumes to clear their sinuses hardly proves
that
> it is a safe thing to do. I know people that smoke and still live to b=
e
100
> too. I'll let Sax be my guide on what safe exposures are vs. "but he d=
id
it
> and didn't get hurt" type stories.
>
> Go ahead and breathe them if you like, but I don't think teaching stude=
nts
> that these fumes are "benign" is a good thing to do.
>
> John
> Web site: http://www.frogpondpottery.com Email: john@frogpondpottery.=
com
>
> "The life so short, the craft so long to learn." Chaucer's translation =
of
> Hippocrates, 5th cent. B.C.
>
> > From: vince pitelka
> >
> > Sorry John, but unless a potter is breathing the fumes straight from =
the
> > stack or ports, there is no danger at all. I have been around a grea=
t
deal
> > of salt firings, and the fumes rise straight up from the ports and
stack,
> > and it would be very difficult to breath those vapors under any
> > circumstance. I agree that no one should be sucking those fumes, but=
we
> > need to maintain a realistic perspective. As you probably know, the
> > historical record shows that in salt-firing factory situations the
workers
> > used to breath the salt fumes eminating from the kiln in order to ope=
n
> > clogged sinuses and nasal passages, with no record of ill effect at a=
ll.
>
>
_________________________________________________________________________=
___
__
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iandol on mon 7 may 01
Dear Vince Pitelka,
Well, I suppose you are right about the record relating to ill health =3D
=66rom Salt Glaze Fumes. But my own experience is that the fumes from suc=
h =3D
a kiln will trigger Asthma and it is not a pleasant experience. I cannot =
=3D
"prove" the attack was caused by breathing salt. But the circumstances =3D
were such that I had done two firings within four days without wearing a =
=3D
mask.
Perhaps the salt glaze kilns you use have been well sealed to prevent =3D
effluent drifting into the atmosphere while you are salting. I have only =
=3D
been able to experience five kilns in action. Two at a nearby community =3D
college, two of my own and that used at a summer school with Jane =3D
Hamlyn.
Firing schedule in all cases was always to close the damper before =3D
placing the salt. This was to ensure there was sufficient time for the =3D
chemical reactions to take place before hot salt was swept out of the =3D
kiln. Even with the gas flow turned down, there was always some fume =3D
backing out of the fire mouths and the cracks round the bricks at the =3D
salt ports. And down draughts can cause contaminated air to circulate =3D
back into the vicinity of people around a kiln.=3D20
I did spend some time visiting most of industrial kilns in England and =3D
Scotland between 1959 and 1969. Whenever I asked managers if I could =3D
observe the salting process, which was usually done at night, I was told =
=3D
"It would be better if you did not breath that stuff" Now their stacks =3D
were far taller than those used in most college kilns. Perhaps their =3D
cumulative experience is of no value in making a safety judgement.
Since industrial salt glazing has been out of fashion for almost half a =3D
century, any deaths which might have occurred would have been treated in =
=3D
the same fashion as many other industrial diseases, such as those cause =3D
by free silica and asbestos. Unless someone is interested enough to make =
=3D
a connection and investigate, and unless there are ways of =3D
discriminating among causes of industrial disease there will be no =3D
record. Though a few breaths of smoke from a salt kiln may have an =3D
effect identical to that of a dose of "Smelling Salts" it is not good =3D
thinking to believe they identical in all other respects? One may be =3D
harmless. The other may lead to a painful death many years after final =3D
exposure (Those German Soldiers died of lead poisoning first. Had there =3D
been no conflict they may have answered the call in another way. Salt =3D
kiln effluent exposure could have contributed fifty years onward)
Put your trust in anecdotes handed down by worked of mouth if you will. =3D
I know what may happen though I could not prove cause, and I will wear a =
=3D
mask the next time I go near a salt glaze kiln.
Best regards,
Ivor Lewis, Redhill, South Australia =3D20
scott lykens on mon 7 may 01
>Charles,
when i was in undergrad the smart guys that installed the new air system in
our art building put the air intake next to our 3 story salt kiln chimney,
next thing you know we were all having to debate this very issue, some folks
came over from a lab in your town, checked us for emissions, while firing
the kiln, no significant level of anything toxic or harmful was found, this
was , as you can imagine, disenchanting to all those fussing about sore
throughts, but according to the emmisions test done nothing at all reached
any dangerious level, . I am not saying that fumes didnt burn eyes or
anyhitng like that, just that the epa and osha have levels for whats bad,
and we never reached them, perhaps its on file in the penn state library. i
heard it was the environmental science department or something like that.
It was suggested by the team of testers that if you were to rub salt in your
eyes or nostril or just eat a big spoon of salt, that it would feel pretty
uncomfortable, but that it would still be salt . I was told that no on site
test data showed proof that heating of salt made a seperation even in the
gaseous stage, and basically its solid salt, liquid salt, or gaseous salt,
but always salt.
anyway, no matter what i,we,you, believe about the story, folks came from
penn state and tested for violating levels of anything, and found nothing
and it could be on file in the library if you look.
Just tryin to help. >Scottt
>We are having a lot of back and forth on this one...has anyone done any
>emissions testing? If so, what specifically does the data say? I have heard
>so many people arguing on this subject and no one has ever cited studies.
>
>-C
>
>
> >
> >
>
>______________________________________________________________________________
>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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Joseph Herbert on mon 7 may 01
I suppose I should apologize to the list for setting off this current
chlorine storm. It was an inadvertent comment in a post asking about firing
with lye (sodium hydroxide) instead of salt or soda. That part of the
question seems to have been obscured by the descending cloud of opposing
hydrogen chloride posts. While I enjoy toxic clouds as much as anyone, I am
still wondering if anyone had participated in, seen, or heard of using lye
as the source of sodium ions in a kiln.
Thank you,
Joseph Herbert
Nils Lou on tue 8 may 01
a couple years ago at nceca there was a report of a carefully controlled
experiment with two identical kilns with carefuly measured loads of tiles
fired and weighed before and after with one kiln salted and one kiln
sodiumed with soda ash. flue gases were analyzed and compared.
interestingly, the salt kiln produced no measureable chlorine, and only a
trace of HCL. 99+% salt vapor--what mom said to breathe when your nose is
stopped up. The soda kiln, however, was not so benign, as there were
deposits and vapors of sodium hudroxide (lye), much more corrosive than
salt vapors. in my opinion, salt ing is no more dangerous than ordinary
reduction firing; i would not use soda ash or sodium bicarbonate (or lye)=
,
however. as usual, vince is the moderate and correct voice in this
discussion=3D- imo.nils lou
On Mon, 7 May 2001, Joseph Herbert wrote:
> I suppose I should apologize to the list for setting off this current
> chlorine storm. It was an inadvertent comment in a post asking about f=
iring
> with lye (sodium hydroxide) instead of salt or soda. That part of the
> question seems to have been obscured by the descending cloud of opposin=
g
> hydrogen chloride posts. While I enjoy toxic clouds as much as anyone,=
I am
> still wondering if anyone had participated in, seen, or heard of using =
lye
> as the source of sodium ions in a kiln.
>
> Thank you,
>
> Joseph Herbert
>
> _______________________________________________________________________=
_______
> 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@pcl=
ink.com.
>
Lee Burningham on tue 8 may 01
Howdy,
Check with John Neely at Utah State University or the transcripts of the
presentation done at Las Vegas NCECA for the particulars. I am now a firm
believer and practitioner of salt over soda firing.
a couple years ago at nceca there was a report of a carefully controlled
experiment with two identical kilns with carefuly measured loads of tiles
fired and weighed before and after with one kiln salted and one kiln
sodiumed with soda ash.
Steve Mills on thu 10 may 01
On the subject of salting and the resulting clouds of vapour, I was
taught the my technique by a superb French Potter Yves Crespel (this
is/was also the standard technique with French rural Potters): putting
small pots of salt in the setting. The salt volatilises early on in the
firing and settles on the wares without being blown right through to the
atmosphere, in fact my experience is that virtually all the vapour stays
in the Kiln. Certainly I don't get any visible effluent. Obviously there
must be some, but definitely not on the scale I have seen in many other
salt Kilns. Incidentally I get a very good glaze on my pots this way.
--
Steve Mills
Bath
UK
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