Tommy Humphries on fri 8 sep 00
I realize that the original question was about electric kilns, but I have a
suggestion for gas kilns...just cut back on the gas for a second, the slight
decrease in temp. will show up by making the cones darker than the
surrounding pots. Works every time, and does not entail any dangers.
Tommy Humphries
----- Original Message -----
From: "chrisclarke"
To:
Sent: Friday, September 08, 2000 3:05 PM
Subject: Re: Seeing Witness Cones
> My ceramics teacher always told us to blow gently into the spy hole (it
does work),
> but now I have a special pair of glasses from an isulation company that
protect my
> eyes. Be careful not to blow too hard, I had dust burn my cornea.
> chris of ccpots
>
> Susan Wallace wrote:
>
> > Dear Clayarters,
> > Once the pots in my electric kiln heat up to orange color, I can't see
the
> > witness cones. Does anyone have any suggestions for making these easier
to
> > see? So far my kiln setter works just fine, but I like to have a back-up
in
> > case one day it fails.
> > Susan in Grand Junction, CO
> >
> >
_________________________________________________________________________
> > Get Your Private, Free E-mail from MSN Hotmail at
http://www.hotmail.com.
> >
> > Share information about yourself, create your own public profile at
> > http://profiles.msn.com.
> >
> >
____________________________________________________________________________
__
> > 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.
>
>
____________________________________________________________________________
__
> 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.
>
Susan Wallace on fri 8 sep 00
Dear Clayarters,
Once the pots in my electric kiln heat up to orange color, I can't see the
witness cones. Does anyone have any suggestions for making these easier to
see? So far my kiln setter works just fine, but I like to have a back-up in
case one day it fails.
Susan in Grand Junction, CO
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
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Anne Hunt on fri 8 sep 00
Hi, Susan --
Same thing happens with me in ^10 gas. I try to place the cones so that
there's no pot directly behind them in my line of view, but can't always do
that. Wearing UV glsses doesn't help, either. Thanks for reminding me and
bringing it up. Thought it was just my "advancing years eyeballs".
Suggestions, anyone?
anne & the cats, who's made the mistake of feeding 5 baby raccoons.
Wade Blocker on fri 8 sep 00
Susan,
CM suggested painting one side of the cones with a strong solution of water
and black stain. I do this in all my firings. Mia in cloudy ABQ
WHC228@AOL.COM on fri 8 sep 00
Susan
First have the cones close enough to the spy hole. Have the spy hole free of
any crumbs. When you want to check the cones, remove the plug and blow gently
through the hole. This will cool the cones enough to see them more easily.
CAUTION Protect your eyes while doing the blowing. Being that close to the
spy hole, could bring your eyes into the heat. I have done it many times and
this works for me. I usually try to stay lower than the plume of heat that
comes from that spy hole.
Bill
DeLana Hornbeck on fri 8 sep 00
Someone helped me with this problem long ago......... the suggestion was to
place the cone pack in front of the coils opposite the peephole you would
use to check them. Of course you have to stack so you can see them and it's
easy to check as you stack, with the lid up and peephole plug removed. When
the kiln is at peak temp, you will see a silouette of the pack in front of
the brighter coils. Hopes this makes sense.
DeLana
----- Original Message -----
From: Susan Wallace
To:
Sent: Friday, September 08, 2000 10:08 AM
Subject: Seeing Witness Cones
> Dear Clayarters,
> Once the pots in my electric kiln heat up to orange color, I can't see
the
> witness cones. Does anyone have any suggestions for making these easier to
> see? So far my kiln setter works just fine, but I like to have a back-up
in
> case one day it fails.
> Susan in Grand Junction, CO
>
> _________________________________________________________________________
> Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
>
> Share information about yourself, create your own public profile at
> http://profiles.msn.com.
>
>
____________________________________________________________________________
__
> 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.
>
chrisclarke on fri 8 sep 00
My ceramics teacher always told us to blow gently into the spy hole (it does work),
but now I have a special pair of glasses from an isulation company that protect my
eyes. Be careful not to blow too hard, I had dust burn my cornea.
chris of ccpots
Susan Wallace wrote:
> Dear Clayarters,
> Once the pots in my electric kiln heat up to orange color, I can't see the
> witness cones. Does anyone have any suggestions for making these easier to
> see? So far my kiln setter works just fine, but I like to have a back-up in
> case one day it fails.
> Susan in Grand Junction, CO
>
> _________________________________________________________________________
> Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
>
> Share information about yourself, create your own public profile at
> http://profiles.msn.com.
>
> ______________________________________________________________________________
> 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.
Dannon Rhudy on fri 8 sep 00
Using a hair dryer to blow a stream of air into the hole also works
very well, in both electric and other kilns. Hold the dryer back
far enough so you don't melt the plastic, and just aim it at the
hole. Works a treat. And you don't have to get close enough to melt
your eyelashes.
regards
Dannon Rhudy
--On Fri, Sep 8, 2000 4:10 PM +0000 WHC228@AOL.COM wrote:
> Susan
> First have the cones close enough to the spy hole. Have the spy hole free
> of any crumbs. When you want to check the cones, remove the plug and blow
> gently through the hole. This will cool the cones enough to see them more
> easily. CAUTION Protect your eyes
Earl Brunner on fri 8 sep 00
paint the side nearest to you with a dark degussa stain like
the red.
Susan Wallace wrote:
>
> Dear Clayarters,
> Once the pots in my electric kiln heat up to orange color, I can't see the
> witness cones. Does anyone have any suggestions for making these easier to
> see? So far my kiln setter works just fine, but I like to have a back-up in
> case one day it fails.
> Susan in Grand Junction, CO
>
> _________________________________________________________________________
> Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
>
> Share information about yourself, create your own public profile at
> http://profiles.msn.com.
>
> ______________________________________________________________________________
> 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.
--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Edward Cowell on sat 9 sep 00
I have a kiln with 3 peepholes and I always fire with the top hole open. When it comes to checking the witness cones, I find it really helps to unplug another hole - the air seems to clear up in a few seconds. Of course, I also use dark goggles.
Laurie Cowell,
Waterloo, Ontario, Canada
Dale A. Neese on sun 10 sep 00
What works for me is the combination of brushing the edge of a cone with
iron oxide. Not the full flat edge, but the sharp edge. If you do it
sparingly you won't affect the cone temp. Place the cones at an angle so
that all can be seen clearly from the peep. Second, pull the damper in a gas
kiln allowing momentary clearing of the atmosphere. Then if you still can't
see the cones, blow with a small diameter pipe directly at the cones. Then
return the damper to the marked reduction position.
Yes, I do wear my protective darkened glasses. There have been times in the
past in teaching situations when the students were making up the cone packs
have misplaced the cones as to temperature and direction of fall. I go back
after making dozens myself for firings and recheck to see if they are
correct.
Firing is the most important part of the process. I try not to have any
interruptions. I try to fire during the day. Used to be able to fire late at
night when I was younger and cutting deadlines close, but getting too
comfortable on the couch after loading can lead me to nod off. One time
missing the reduction cone or sleeping past cone 11 one time will cure you
of that. Whole nuther sad story.
I ask that visitors please come back when the firing is finished if they
can. If you don't explain to the people that the kiln area is off limits,
they are usually trying to put their eye up to the peep hole or their
wandering kids can get burned. Never had it happen but not much the kiln god
can do to protect them. Never leave the kiln when it is firing. Electric or
gas. How many posts to the list I have seen about peoples gas going off or
kiln sitters not cutting off when they are absent. Full scale disaster. I
don't think factory warranties cover carelessness. One kiln suppliers show
room I know of has an electric kiln with a whole load of pots and shelves
melted into a mass in the bottom of it. Frightening example.
Dale Tex
ferenc jakab on sun 10 sep 00
> Susan,
> CM suggested painting one side of the cones with a strong solution of
water
> and black stain. I do this in all my firings. Mia in cloudy ABQ
Mia,
this is risky as it might change the melting point of the cone.
Never having fired an electric kiln until recently (I like to see the
flame) I was surprised at how cloudy this supposedly neutral firing was. I
too would be interested in why this cloudiness occurs in an electric kiln.
Feri.
pedresel on sun 10 sep 00
Hmmm,
I thought the cloudiness was due to black body radiation of the air
itself so you in effect have light coming at you from between you and
the object -- thus you get haze. So you aren't cooling the cones by
blowing on them but cooling the air so it actually is clearer.
Can't say where I got this idea so it could be a crock. Let's send a
kiln up on the next space shuttle and see what happens in a vacuum.
-- Evan in W Richland WA where it rained again.
Larry Phillips wrote:
>
> ferenc jakab wrote:
>
> > Never having fired an electric kiln until recently (I like to see the
> > flame) I was surprised at how cloudy this supposedly neutral firing was. I
> > too would be interested in why this cloudiness occurs in an electric kiln.
>
> I don't think it is 'cloudiness', which is to say I don't think it's the
> result of airborne particles.
>
.....
>
> When you blow into the spyhole to see a cone, it looks a lot like you
> are
> clearing the air in the kiln, because all of a sudden, you see the cone.
> This, though, is not the reason you see the cone. You see it because you
> have cooled it a little bit, and it is now a different temperature than
> the
> objects behind it. This changes the spectrum of the light it is
> radiating,
> and you now have more contrast, allowing you to distinguish it from the
> rest of the kiln and objects in it.
>
> In the case of a wood or gas kiln, you have two problems. The first is
> that
> there are airborne particles, which must be cleared before you can see,
> and the other is the same as above, which is true for any kiln,
> regardless
> of what made it hot.
>
> If you want to know more about this subject, the place to start is with
> a
> web search for the phrase 'black body radiation'.
>
> --
> Hukt on fonix werkt fer me!
>
> http://cr347197-a.surrey1.bc.wave.home.com/larry/
>
> ______________________________________________________________________________
> 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.
Coolpots@AOL.COM on sun 10 sep 00
The easiest and safe way to see your witness cones is to brush them with red
iron oxide mixed with a little water. Someone mentioned it on Clayart several
months ago and it works like a charm!
Vicki in Cool, CA
Larry Phillips on sun 10 sep 00
ferenc jakab wrote:
> Never having fired an electric kiln until recently (I like to see the
> flame) I was surprised at how cloudy this supposedly neutral firing was. I
> too would be interested in why this cloudiness occurs in an electric kiln.
I don't think it is 'cloudiness', which is to say I don't think it's the
result of airborne particles.
The problem is one of contrast. The reason we can visually distinguish
one
object from another is that different objects are different colours, or
different intensities of the same colour (which effectively makes it a
different colour). If an object's colour matches its background
perfectly,
you will not be able to distinguish object from background.
The reason objects are different colours is because light reflects off
them
differently, each reflecting a particular set of light frequencies, in a
particular set of intensities.
In a kiln that is hot enough to glow orange, red, yellow, or white, you
are
no longer looking primarily at the light reflected from the objects (or
kiln),
but are looking at light _produced_ by the objects themselves, as a
direct
result of the heat (energy of its molecules). Each object is radiating a
set
of frequencies that is mostly dependent on its temperature, rather than
on the
qualities of its surface. Thus, there is little contrast between
objects, and
the result is what you perceive as 'cloudiness'. Any contrast you do see
is
mostly a result of the thermal characteristics of the objects, some of
which
will pick up or lose heat at different rates as the temperature changes
within
the kiln.
When you blow into the spyhole to see a cone, it looks a lot like you
are
clearing the air in the kiln, because all of a sudden, you see the cone.
This, though, is not the reason you see the cone. You see it because you
have cooled it a little bit, and it is now a different temperature than
the
objects behind it. This changes the spectrum of the light it is
radiating,
and you now have more contrast, allowing you to distinguish it from the
rest of the kiln and objects in it.
In the case of a wood or gas kiln, you have two problems. The first is
that
there are airborne particles, which must be cleared before you can see,
and the other is the same as above, which is true for any kiln,
regardless
of what made it hot.
If you want to know more about this subject, the place to start is with
a
web search for the phrase 'black body radiation'.
--
Hukt on fonix werkt fer me!
http://cr347197-a.surrey1.bc.wave.home.com/larry/
GSM_ENT on sun 10 sep 00
Hi!
With a proper base test firing you do not need to watch your witness cones.
As a matter of fact watching your cones throught the peepholes has been
proven to harm your eyes, not to mention the risk of burning yourself.
If you want the instructions on base test firing please contact me at my
private E-Mail address as attachments here are not allowed or recommended.
If you would rather get a "hard copy" please send your postal address to my
E-Mail address.
Tony
----- Original Message -----
From: Wade Blocker
To:
Sent: Friday, September 08, 2000 12:08 PM
Subject: seeing witness cones
> Susan,
> CM suggested painting one side of the cones with a strong solution of
water
> and black stain. I do this in all my firings. Mia in cloudy ABQ
>
>
____________________________________________________________________________
__
> 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.
Steve Mills on sun 10 sep 00
Some of our customers tell us that laying a cone on its side over the
edge of a piece of shelf or similar makes them easier to see, when they
hang vertical they're done!.
Steve
Bath
UK
In message , Anne Hunt writes
>Hi, Susan --
> Same thing happens with me in ^10 gas. I try to place the cones so that
>there's no pot directly behind them in my line of view, but can't always do
>that. Wearing UV glsses doesn't help, either. Thanks for reminding me and
>bringing it up. Thought it was just my "advancing years eyeballs".
> Suggestions, anyone?
>
>anne & the cats, who's made the mistake of feeding 5 baby raccoons.
>
--
Steve Mills
Bath
UK
ed on sun 10 sep 00
-----Original Message-----
From: GSM_ENT
To: CLAYART@LSV.CERAMICS.ORG
Date: Sunday, September 10, 2000 3:05 PM
Subject:GSM_ENT seeing witness cones
>
>With aWHAT DOES "proper base test firing" MEAN???? HOW ELSE CAN I KNOW THAT
MY KILN FIRING HAS GONE TO CONE 06 UNLESS I LOOK AT THE CONES AND SEE THEM
BEND???
Jennifer F Boyer on mon 11 sep 00
Hi Tony,
When you talk about calibrating the kiln to the cones, are you
talking about using an electronic device to fire the kiln? Your
statement doesn't pertain to any of the kilns I own, since I
don't use electronic pyrometers. Maybe the group would get more
out of your point of view if you explain what kind of equipment
you are using.....Clayart is worldwide, and there are many kinds
of kilns and levels of technological sophistication represented.
Also I would love to know the source material you used for your
research in eye damage. I've never heard of this point of view
that welding glass isn't safe. Can you point me towards any articles/books?
Thanks so much
Jennifer
GSM_ENT wrote:
>
> Hi!
>
> There is a relationship between firing cone and witness cones. The kiln
> needs to be "calibrated" for the firing cone being fired. Once this is done
> you do not need to be watching the cone.
>
> Looking into the hot kiln is harmfull to your eyes. If you "must" take a
> piece of mirror and positione it so that you can look at the mirron and see
> inside the kiln.
>
> Tony
> ----- Original Message -----
> From: ed
> To:
> Sent: Sunday, September 10, 2000 4:27 PM
> Subject: Re: seeing witness cones
>
> > -----Original Message-----
> > From: GSM_ENT
> > To: CLAYART@LSV.CERAMICS.ORG
> > Date: Sunday, September 10, 2000 3:05 PM
> > Subject:GSM_ENT seeing witness cones
> >
> >
> >
> > >
> > >With aWHAT DOES "proper base test firing" MEAN???? HOW ELSE CAN I KNOW
> THAT
> > MY KILN FIRING HAS GONE TO CONE 06 UNLESS I LOOK AT THE CONES AND SEE THEM
> > BEND???
> >
> >
> ____________________________________________________________________________
> __
> > 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.
>
> ______________________________________________________________________________
> 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.
--
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Jennifer Boyer jboyer@adelphia.net
Thistle Hill Pottery
Vermont USA
http://www.thistlehillpottery.com/
Check out this searchable sites about web hoaxes:
http://urbanlegends.about.com/science/urbanlegends/library/blhoax.htm
~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
Larry Phillips on mon 11 sep 00
pedresel wrote:
>
> Hmmm,
>
> I thought the cloudiness was due to black body radiation of the air
> itself so you in effect have light coming at you from between you and
> the object -- thus you get haze. So you aren't cooling the cones by
> blowing on them but cooling the air so it actually is clearer.
Well, if you cool the air, it just radiates slightly differently.
If you look at a spectrum chart that shows temperature vs. radiation,
you'll see that what you are actually looking at is the higher frequency
part of a sort of a 'stretched bell curve'. At lower frequencies, this
is more like a bell curve, and is entirely below the visible light
frequencies. As the temperature rises the top end of the curve (the
higher frequency end) moves more and more into the visible spectrum.
So, you may be right, in that you reduce the amount of visible radiation
coming from the air, and this, make it 'clearer' by reducing the amount
of radiation coming from the air between you and the cones.
That having been said, I know that when I blow into the kiln, the cones
definitely cool slightly, and I know this because I see the edges go a
lot darker than the flat parts. Of course, with my small kiln, the cones
may be closer than you are used to. I set them up about 5-6" from the
spyhole.
A good experiment to try (and I may do it the next time I bisque fire),
would be to use a small stainless steel tube to direct some air onto a
cone. The cone will darken where the air hits it, of course, but it
should be instructive to note whether or not it becomes just as visible
as when you blow into the entire spyhole, or whether it still looks
'cloudy'.
--
Hukt on fonix werkt fer me!
http://cr347197-a.surrey1.bc.wave.home.com/larry/
Earl Brunner on mon 11 sep 00
That's why I suggested painting a strip of Dark Degussa
Stain on them, encapsulated zirconium stains should not
affect the melt of the cone.
Dave Finkelnburg wrote:
>
> Tim,
> I suspect yuo may have answered this question before. If so, please
> bear with me. How does Orton feel about the suggestion which has been made
> a few times to the list to paint a stripe of oxide on the cone intself to
> improve its visibility? Thanks!
> Dave Finkelnburg
>
> -----Original Message-----
> From: Frederich, Tim
> Date: Monday, September 11, 2000 7:51 AM
> Subject: Re: Seeing Witness Cones
>
> >To all concerned,
> > When you blow air into the kiln to view the cones you may freeze
> the
> >cones if they have started to go into any kind of melt phase. This will
> >change the reading of the cone and could change it to a large extent. We do
> >not reccomend blowing into the kiln chamber at all.
> >Tim Frederich, Orton Ceramic Foundation
>
> ______________________________________________________________________________
> 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.
--
Earl Brunner
http://coyote.accessnv.com/bruec
mailto:bruec@anv.net
Suzanne Wolfe on mon 11 sep 00
Tim,
Thanks very much for your input on this situation. As you can see, there
are many ceramics people out here who do have the same problem, so it
would be very important, from my point of view, for you to share more
information here. I have also heard that blowing into the kiln could
freeze the cones (didn't know why, however), and it would stand to reason
that spraying water into the kiln could cause similar problems. I would
like to know what the recommendations (and admonitions) from Orton are.
Thanks.
Suzanne Wolfe
On Mon, 11 Sep 2000, Frederich, Tim wrote:
> To all concerned,
> When you blow air into the kiln to view the cones you may freeze the
> cones if they have started to go into any kind of melt phase. This will
> change the reading of the cone and could change it to a large extent. We do
> not reccomend blowing into the kiln chamber at all.
>
> Tim Frederich, Orton Ceramic Foundation
>
> -----Original Message-----
> From: Dannon Rhudy [mailto:drhudy@LINFIELD.EDU]
> Sent: Friday, September 08, 2000 9:19 PM
> To: CLAYART@LSV.CERAMICS.ORG
> Subject: Re: Seeing Witness Cones
>
>
> Using a hair dryer to blow a stream of air into the hole also works
> very well, in both electric and other kilns. Hold the dryer back
> far enough so you don't melt the plastic, and just aim it at the
> hole. Works a treat. And you don't have to get close enough to melt
> your eyelashes.
>
> regards
>
> Dannon Rhudy
>
>
>
> --On Fri, Sep 8, 2000 4:10 PM +0000 WHC228@AOL.COM wrote:
>
> > Susan
> > First have the cones close enough to the spy hole. Have the spy hole free
> > of any crumbs. When you want to check the cones, remove the plug and blow
> > gently through the hole. This will cool the cones enough to see them more
> > easily. CAUTION Protect your eyes
>
> ____________________________________________________________________________
> __
> 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.
>
> ______________________________________________________________________________
> 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.
>
Frederich, Tim on mon 11 sep 00
Susan,
The best way to see the cones inside the kiln is to use a pair of
safety glasses with a shade 3 or darker lens to protect your eyes. You can
also place a piece of insulation brick about 3/4 inch behind the cones with
some lines of Red Iron Oxide drawn on the brick. This makes a good
background to view the cones. It is always a good idea to use witness cones
so I hope this helps you.
Tim Frederich, Orton Ceramic Foundation
-----Original Message-----
From: Susan Wallace [mailto:suewallace48@HOTMAIL.COM]
Sent: Friday, September 08, 2000 11:08 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Seeing Witness Cones
Dear Clayarters,
Once the pots in my electric kiln heat up to orange color, I can't see the
witness cones. Does anyone have any suggestions for making these easier to
see? So far my kiln setter works just fine, but I like to have a back-up in
case one day it fails.
Susan in Grand Junction, CO
_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
Share information about yourself, create your own public profile at
http://profiles.msn.com.
____________________________________________________________________________
__
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.
Frederich, Tim on mon 11 sep 00
To all concerned,
When you blow air into the kiln to view the cones you may freeze the
cones if they have started to go into any kind of melt phase. This will
change the reading of the cone and could change it to a large extent. We do
not reccomend blowing into the kiln chamber at all.
Tim Frederich, Orton Ceramic Foundation
-----Original Message-----
From: Dannon Rhudy [mailto:drhudy@LINFIELD.EDU]
Sent: Friday, September 08, 2000 9:19 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Seeing Witness Cones
Using a hair dryer to blow a stream of air into the hole also works
very well, in both electric and other kilns. Hold the dryer back
far enough so you don't melt the plastic, and just aim it at the
hole. Works a treat. And you don't have to get close enough to melt
your eyelashes.
regards
Dannon Rhudy
--On Fri, Sep 8, 2000 4:10 PM +0000 WHC228@AOL.COM wrote:
> Susan
> First have the cones close enough to the spy hole. Have the spy hole free
> of any crumbs. When you want to check the cones, remove the plug and blow
> gently through the hole. This will cool the cones enough to see them more
> easily. CAUTION Protect your eyes
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GSM_ENT on mon 11 sep 00
Hi!
There is a relationship between firing cone and witness cones. The kiln
needs to be "calibrated" for the firing cone being fired. Once this is done
you do not need to be watching the cone.
Looking into the hot kiln is harmfull to your eyes. If you "must" take a
piece of mirror and positione it so that you can look at the mirron and see
inside the kiln.
Tony
----- Original Message -----
From: ed
To:
Sent: Sunday, September 10, 2000 4:27 PM
Subject: Re: seeing witness cones
> -----Original Message-----
> From: GSM_ENT
> To: CLAYART@LSV.CERAMICS.ORG
> Date: Sunday, September 10, 2000 3:05 PM
> Subject:GSM_ENT seeing witness cones
>
>
>
> >
> >With aWHAT DOES "proper base test firing" MEAN???? HOW ELSE CAN I KNOW
THAT
> MY KILN FIRING HAS GONE TO CONE 06 UNLESS I LOOK AT THE CONES AND SEE THEM
> BEND???
>
>
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Ray Aldridge on mon 11 sep 00
At 08:07 AM 9/11/00 -0400, you wrote:
>To all concerned,
> When you blow air into the kiln to view the cones you may freeze the
>cones if they have started to go into any kind of melt phase. This will
>change the reading of the cone and could change it to a large extent. We do
>not reccomend blowing into the kiln chamber at all.
>
>Tim Frederich, Orton Ceramic Foundation
I hate to argue with folks who know more about the subject than I do, but
this seems very unlikely to me. The effect is momentary, and obviously
involves only the surface of the cone-- one would have to run air over the
cone for an awfully long time to "freeze" it to the core. It's obvious
from observation that the effect of blowing air into the kiln lasts only a
second or so, after which the temperature on the surface of the cone again
rises to match that of the surrounding ware. Also, since the cone measures
not temperature but work heat, it's hard to see how a few seconds of
slightly reduced temperatures over the course of a firing that last many
hours could have much effect on the endpoint of the cones. As anyone who's
fired a wood kiln can tell you, the fluctuations in temperature as you
stoke are far greater than fluctuations caused by a little cool air hitting
the cones.
I'd have to see actual data derived from realworld experimentation before I
could take this warning very seriously.
Ray
http://goodpots.com/
Dave Finkelnburg on mon 11 sep 00
Tim,
I suspect yuo may have answered this question before. If so, please
bear with me. How does Orton feel about the suggestion which has been made
a few times to the list to paint a stripe of oxide on the cone intself to
improve its visibility? Thanks!
Dave Finkelnburg
-----Original Message-----
From: Frederich, Tim
Date: Monday, September 11, 2000 7:51 AM
Subject: Re: Seeing Witness Cones
>To all concerned,
> When you blow air into the kiln to view the cones you may freeze
the
>cones if they have started to go into any kind of melt phase. This will
>change the reading of the cone and could change it to a large extent. We do
>not reccomend blowing into the kiln chamber at all.
>Tim Frederich, Orton Ceramic Foundation
Michael Banks on tue 12 sep 00
Red hot air! Of course. And matter when it is incandescent, is
essentially black to incident light. So the red-hot air molecules are
absorbing light coming from behind -in the line of sight and partially
blocking the light. Like a dusty sunset, hazy.
But this raises another point: Those potters who go to the trouble of
painting their cones with dark pigments, could (in theory) be wasting their
time... Because cones glowing with incandescent light (black body
radiation) should all be black anyway!
Michael in NZ,
where Spring has sprung..
----- Original Message -----
Evan in W Richland WA wrote:
> Hmmm,
>
> I thought the cloudiness was due to black body radiation of the air
> itself so you in effect have light coming at you from between you and
> the object -- thus you get haze. So you aren't cooling the cones by
> blowing on them but cooling the air so it actually is clearer.
Frederich, Tim on tue 12 sep 00
Dave,
Orton does not reccomend painting any kind of oxide or stain on a
cone to help see it in the kiln. When you add another chemical to the cone
you can change the melting characteristics when the cone starts to form
glass as it reaches temperature. This can give you a large error in the
reading of the cone. As stated earlier, use good safety glasses and possibly
a target behind the cones to view them agianst. Please go to our web site if
you would like more information.(www.ortonceramic.com)
Tim Frederich, Orton Ceramic Foundation
-----Original Message-----
From: Dave Finkelnburg [mailto:dfinkeln@CYBERHIGHWAY.NET]
Sent: Monday, September 11, 2000 5:51 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Seeing Witness Cones
Tim,
I suspect yuo may have answered this question before. If so, please
bear with me. How does Orton feel about the suggestion which has been made
a few times to the list to paint a stripe of oxide on the cone intself to
improve its visibility? Thanks!
Dave Finkelnburg
-----Original Message-----
From: Frederich, Tim
Date: Monday, September 11, 2000 7:51 AM
Subject: Re: Seeing Witness Cones
>To all concerned,
> When you blow air into the kiln to view the cones you may freeze
the
>cones if they have started to go into any kind of melt phase. This will
>change the reading of the cone and could change it to a large extent. We do
>not reccomend blowing into the kiln chamber at all.
>Tim Frederich, Orton Ceramic Foundation
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Frederich, Tim on tue 12 sep 00
Ray,
It only takes a short blast of air on the outside of the cone to
cause the freezing effect if the cone is at a certain stage of the melt. We
do have examples of this at Orton. The air is affecting the glass crystals
that are being formed. These crystals might take a higher temperature to
melt again if they were stopped during a certain stage. This only happens
over a short period of time for each cone number as it is melting even
though the firing may take many hours. Wood kilns can affect the reading of
the cone from the drafts and the ash flying through the chamber. We
reccomend a shelter over the cones if this becomes a problem for people.
Cones do not always give an accurate indication of heatwork when they are in
an atmosphere such as a wood kiln, but they are still one of the best
methods available.
Tim Frederich, Orton Ceramic Foundation
-----Original Message-----
From: Ray Aldridge [mailto:pbwriter@FWB.GULF.NET]
Sent: Monday, September 11, 2000 2:07 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Seeing Witness Cones
At 08:07 AM 9/11/00 -0400, you wrote:
>To all concerned,
> When you blow air into the kiln to view the cones you may freeze
the
>cones if they have started to go into any kind of melt phase. This will
>change the reading of the cone and could change it to a large extent. We do
>not reccomend blowing into the kiln chamber at all.
>
>Tim Frederich, Orton Ceramic Foundation
I hate to argue with folks who know more about the subject than I do, but
this seems very unlikely to me. The effect is momentary, and obviously
involves only the surface of the cone-- one would have to run air over the
cone for an awfully long time to "freeze" it to the core. It's obvious
from observation that the effect of blowing air into the kiln lasts only a
second or so, after which the temperature on the surface of the cone again
rises to match that of the surrounding ware. Also, since the cone measures
not temperature but work heat, it's hard to see how a few seconds of
slightly reduced temperatures over the course of a firing that last many
hours could have much effect on the endpoint of the cones. As anyone who's
fired a wood kiln can tell you, the fluctuations in temperature as you
stoke are far greater than fluctuations caused by a little cool air hitting
the cones.
I'd have to see actual data derived from realworld experimentation before I
could take this warning very seriously.
Ray
http://goodpots.com/
____________________________________________________________________________
__
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You may look at the archives for the list or change your subscription
settings from http://www.ceramics.org/clayart/
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Bruce Girrell on tue 12 sep 00
Tim Frederich wrote:
> It only takes a short blast of air on the outside of the cone to
>cause the freezing effect if the cone is at a certain stage of the melt. We
>do have examples of this at Orton. The air is affecting the glass crystals
>that are being formed. These crystals might take a higher temperature to
>melt again if they were stopped during a certain stage.
Tim,
Please be careful how you state things when you are providing a technical
answer. The way in which you answered this question casts great doubt on the
veracity of it. Glass is, by definition, not crystalline. I believe I
understand what you are trying to say, but your use of contradictory terms
implies that you don't understand what you're talking about in what should
be an area of expertise for you.
Bruce "Mr. Picky" Girrell
Ray Aldridge on tue 12 sep 00
At 08:14 AM 9/12/00 -0400, you wrote:
>Ray,
> It only takes a short blast of air on the outside of the cone to
>cause the freezing effect if the cone is at a certain stage of the melt. We
>do have examples of this at Orton.
I understand the theory you're putting forward, but I'm still a skeptic-- I
guess because in 30 years I've never observed the effect you're referring to.
I suppose what I need to do is to test the theory for myself. Tell me if
you see any theoretical flaws in this protocol: I'll set up two sets of
cones on the same shelf in a circular electric kiln (using self-supporting
cones to avoid differences in angle.) I'll put one set in front of the
peephole and the other across the shelf, the same distance in from the
elements. I'll protect the latter with a softbrick barrier to avoid any
air impinging on it. Then during the endpoint of the firing, I'll blow
like hell on the cones in front of the peep, and see if there is any
visible difference between the two sets, after the firing.
Ray
http://goodpots.com/
Frederich, Tim on tue 12 sep 00
Ray,
Please try and let me know the results. Thanks.
Tim
-----Original Message-----
From: Ray Aldridge [mailto:pbwriter@FWB.GULF.NET]
Sent: Tuesday, September 12, 2000 2:41 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Seeing Witness Cones
At 08:14 AM 9/12/00 -0400, you wrote:
>Ray,
> It only takes a short blast of air on the outside of the cone to
>cause the freezing effect if the cone is at a certain stage of the melt. We
>do have examples of this at Orton.
I understand the theory you're putting forward, but I'm still a skeptic-- I
guess because in 30 years I've never observed the effect you're referring
to.
I suppose what I need to do is to test the theory for myself. Tell me if
you see any theoretical flaws in this protocol: I'll set up two sets of
cones on the same shelf in a circular electric kiln (using self-supporting
cones to avoid differences in angle.) I'll put one set in front of the
peephole and the other across the shelf, the same distance in from the
elements. I'll protect the latter with a softbrick barrier to avoid any
air impinging on it. Then during the endpoint of the firing, I'll blow
like hell on the cones in front of the peep, and see if there is any
visible difference between the two sets, after the firing.
Ray
http://goodpots.com/
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Frederich, Tim on wed 13 sep 00
Dear Bruce,
Thanks for your reply and analysis. I quickly replied without
proofing my statement and was trying to keep it simple. It is the glass that
is formed during heating that could recrystallize if a sudden cooling effect
takes place. The result could change the composition yielding a higher
melting body. What is formed is dependent on the original composition and
temperature. I hope this explains the problem in a better manner.
Tim Frederich, Orton Ceramic Foundation
-----Original Message-----
From: Bruce Girrell [mailto:bigirrell@MICROLINETC.COM]
Sent: Tuesday, September 12, 2000 12:38 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Seeing Witness Cones
Tim Frederich wrote:
> It only takes a short blast of air on the outside of the cone to
>cause the freezing effect if the cone is at a certain stage of the melt. We
>do have examples of this at Orton. The air is affecting the glass crystals
>that are being formed. These crystals might take a higher temperature to
>melt again if they were stopped during a certain stage.
Tim,
Please be careful how you state things when you are providing a technical
answer. The way in which you answered this question casts great doubt on the
veracity of it. Glass is, by definition, not crystalline. I believe I
understand what you are trying to say, but your use of contradictory terms
implies that you don't understand what you're talking about in what should
be an area of expertise for you.
Bruce "Mr. Picky" Girrell
____________________________________________________________________________
__
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/
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