Fredrick Paget on fri 20 jan 06
Now take a look at:
http://lectureonline.cl.msu.edu/~mmp/applist/blackbody/black.htm
Once there you can slide the Kelvin temperature scale up and down
with the mouse on the thermometer figure and the other two graphs
move. At usual kiln temperature there is very little UV If you
advance the temperature way beyond what we work at you see the curve
range upward in the UV. The UV is over at the left on the graph with
the rainbow.
A black body radiator is a sort of idealized thing that approximates
a kiln. We can look at the blackbody radiation versus temperature
which obeys a law of physics and get a pretty good idea of the
radiation that comes out of a kiln.
The temperature is expressed in degrees Kelvin which is a scale that
starts from absolute zero but the degrees are the same size as
centigrade degrees. so just subtract 273 from degrees Kelvin and you
have centigrade.
--
From Fred Paget,
Marin County, CA, USA
fredrick@well.com
http://homepage.mac.com/fredrick/FileSharing1.html
Charter Member Potters Council
Marcia Selsor on fri 20 jan 06
All this talk about firing by color is fine BUT here is a story.
Remember Adelaide Robineau of the Thousand Hour vase?
Her sweet helpful husband, Samuel Robineau, fired her crystalline
glazes by eye.
He judged the soaking periods, etc without protecting his eyes.
He went blind.
Just remember, our bodies are our best tools. Take care of them..eyes
included.
Use goggles for UV protaction. Sorry but you can't judge color
through them very well.
Marcia Selsor
2ley on fri 20 jan 06
From: "Marcia Selsor"
> Use goggles for UV protaction. Sorry but you can't judge color
> through them very well.
I wonder a bit at this. According to the manufacturer of my eyeglasses, I
have 100% blocking of UV A and B. The lenses are not tinted. Is it
possible to get untinted, but fully protective, goggles?
Philip Tuley
Jody on fri 20 jan 06
Does this include Raku firing?
Jody Rath
----- Original Message -----
From: "Marcia Selsor"
To:
Sent: Friday, January 20, 2006 12:24 PM
Subject: Re: firing by color/remember your eyes!
> All this talk about firing by color is fine BUT here is a story.
> Remember Adelaide Robineau of the Thousand Hour vase?
> Her sweet helpful husband, Samuel Robineau, fired her crystalline
> glazes by eye.
> He judged the soaking periods, etc without protecting his eyes.
> He went blind.
> Just remember, our bodies are our best tools. Take care of them..eyes
> included.
> Use goggles for UV protaction. Sorry but you can't judge color
> through them very well.
>
> Marcia Selsor
>
> ______________________________________________________________________________
> 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.
>
Fredrick Paget on fri 20 jan 06
There is very little or no UV coming out of a hot kiln.
What you have is a lot of infared and visible light that is in the
red end of the spectrum.
Number 3 welding lenses will stop the infared. Plain glass absorbs a
lot of the UV end of the spectrum .
--
From Fred Paget,
Marin County, CA, USA
fredrick@well.com
http://homepage.mac.com/fredrick/FileSharing1.html
Charter Member Potters Council
Marcia Selsor on fri 20 jan 06
Phillip,
Interesting idea. I don't know! But you have an excellent point.
Marcia
On Jan 20, 2006, at 2:18 PM, 2ley wrote:
> From: "Marcia Selsor"
>> Use goggles for UV protaction. Sorry but you can't judge color
>> through them very well.
>
> I wonder a bit at this. According to the manufacturer of my
> eyeglasses, I
> have 100% blocking of UV A and B. The lenses are not tinted. Is it
> possible to get untinted, but fully protective, goggles?
>
> Philip Tuley
Jennifer Buckner on fri 20 jan 06
At 04:18 PM 1/20/2006, Phil Tuley wrote:
According to the manufacturer of my eyeglasses, I
>have 100% blocking of UV A and B. The lenses are not tinted. Is it
>possible to get untinted, but fully protective, goggles?
Phil,
Would you mind sharing the brand name of these goggles?
Jennifer (Northern VT)
Jennifer G. Buckner jennifer@buckner.cc
Marcia Selsor on fri 20 jan 06
Yes.
The higher the temperature especially intense heat, the more high
energy photons are emitted.
If you think about warnings for watching the sun in an eclipse, this
is the reason.
I have fired raku by color for many years. But I use a pyrometer now.
I think age brings a certain wisdom of taking care of yourself.
Marcia in Montana
On Jan 20, 2006, at 3:35 PM, Jody wrote:
> Does this include Raku firing?
>
> Jody Rath
> ----- Original Message -----
> From: "Marcia Selsor"
> To:
> Sent: Friday, January 20, 2006 12:24 PM
> Subject: Re: firing by color/remember your eyes!
>
>
>> All this talk about firing by color is fine BUT here is a story.
>> Remember Adelaide Robineau of the Thousand Hour vase?
>> Her sweet helpful husband, Samuel Robineau, fired her crystalline
>> glazes by eye.
>> He judged the soaking periods, etc without protecting his eyes.
>> He went blind.
>> Just remember, our bodies are our best tools. Take care of them..eyes
>> included.
>> Use goggles for UV protaction. Sorry but you can't judge color
>> through them very well.
>>
>> Marcia Selsor
>>
>> _____________________________________________________________________
>> _________
>> 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.
>
Lori Doty on fri 20 jan 06
Yes. Just remember what your mother told you (or should have) don't
stare at the sun, nor anything else that can melt the skin off your
hands in an instant. (Liquid cleansers not withstanding)
Lori Doty
Nurse/Potter
Slowly turning the tide.
On Jan 20, 2006, at 4:35 PM, Jody wrote:
> Does this include Raku firing?
>
> Jody Rath
> ----- Original Message -----
> From: "Marcia Selsor"
> To:
> Sent: Friday, January 20, 2006 12:24 PM
> Subject: Re: firing by color/remember your eyes!
>
>
>> All this talk about firing by color is fine BUT here is a story.
>> Remember Adelaide Robineau of the Thousand Hour vase?
>> Her sweet helpful husband, Samuel Robineau, fired her crystalline
>> glazes by eye.
>> He judged the soaking periods, etc without protecting his eyes.
>> He went blind.
>> Just remember, our bodies are our best tools. Take care of them..eyes
>> included.
>> Use goggles for UV protaction. Sorry but you can't judge color
>> through them very well.
>>
>> Marcia Selsor
>>
>> ______________________________________________________________________
>> ________
>> 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.
>
Edouard Bastarache Inc. on fri 20 jan 06
Read my article on Eye Injuries Due to Radiation
http://perso.wanadoo.fr/smart2000/Lesions_yeux.htm#English%20version
Kilns do not emit UV but Infra-Reds, these
decrease in energy following this function
1/d², where "d" stands for distance.
So 3 feet away from the peephole of a kiln,
such as a fossil kiln, the energy recieved is very low.
You can test this with your hand in an electric kiln also,
in a top-loader electric kiln, put your hand as close as
you can to a red element and then move it away slowly
and you will see that 3 feet away you nearly do not feel
anything at all. I recently made this demonstration to a
construction worker I was arguing with.
I presume the same thing could be tested in a front-loader.
Also, we recently had a lady-clayarter by the name of Julie
who worked many years for a group of eye-specialists and
their opinion was that the trade of potter was not one in which
we could encounter cataracts which is what I wrote in the
conclusion of my article.
Later,
"Ils sont fous ces quebecois"
"They are insane these quebekers"
"Están locos estos quebequeses"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
www.sorel-tracy.qc.ca/~edouardb/Welcome.html
http://retrodemonstration.blogspot.com/
http://www.flickr.com/photos/potier/
http://stainlessfre.blogspot.com/
http://perso.wanadoo.fr/smart2000/index.htm
mtigges@NOSPAM.SHAW.CA on fri 20 jan 06
On Fri, Jan 20, 2006 at 01:18:05PM -0800, 2ley wrote:
> From: "Marcia Selsor"
> >Use goggles for UV protaction. Sorry but you can't judge color
> >through them very well.
>
> I wonder a bit at this. According to the manufacturer of my eyeglasses, I
> have 100% blocking of UV A and B. The lenses are not tinted. Is it
> possible to get untinted, but fully protective, goggles?
>
You should be able to judge just fine. The goggles filter out a
portion of the spectrum which is invisible, and merely reduce the
amplitude of the visible. So, the information is there, it's just
different. I agree with Marcia. USE GOGGLES.
The first time I checked witness cones I did it without protection,
and my eyes hurt for the next 24 hours.
Best regards,
Mark.
Marcia Selsor on fri 20 jan 06
Right Fred. Thanks. Infra Red...I always get those two mixed up.
Marcia
On Jan 20, 2006, at 6:36 PM, Fredrick Paget wrote:
> There is very little or no UV coming out of a hot kiln.
> What you have is a lot of infared and visible light that is in the
> red end of the spectrum.
> Number 3 welding lenses will stop the infared. Plain glass absorbs a
> lot of the UV end of the spectrum .
> --
> From Fred Paget,
> Marin County, CA, USA
> fredrick@well.com
> http://homepage.mac.com/fredrick/FileSharing1.html
> Charter Member Potters Council
>
> ______________________________________________________________________
> ________
> 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.
>
Hank Murrow on fri 20 jan 06
On Jan 20, 2006, at 5:36 PM, Fredrick Paget wrote:
> There is very little or no UV coming out of a hot kiln.
> What you have is a lot of infared and visible light that is in the
> red end of the spectrum.
> Number 3 welding lenses will stop the infared. Plain glass absorbs a
> lot of the UV end of the spectrum .
Glass blowers lenses mounted in a safety frame will completely block
the IRspectrum. The ones I use are Didymium lenses. Got the lenses at a
weldors' supply, and glass blowing supply houses have them also. Nice
thing is they don't diminish visible light much........ though
providing a rosy view of life...... and the cones.
Cheers, Hank
www.murrow.biz/hank
Snail Scott on sat 21 jan 06
At 01:18 PM 1/20/2006 -0800, you wrote:
>From: "Marcia Selsor"
>> Use goggles for UV protaction. Sorry but you can't judge color
>> through them very well.
>
>I wonder a bit at this. According to the manufacturer of my eyeglasses, I
>have 100% blocking of UV A and B. The lenses are not tinted. Is it
>possible to get untinted, but fully protective, goggles?
Kilns put out very little UV radiation, but
LOTS of IR radiation. Glassblower's goggles
are untinted, and supposedly give a lot of
protection. I use them for judging color,
but stick to the green welder's goggles for
checking cones and most other close-up looking.
To be honest, I don't use the glassblower's
goggles often. Seems to me that if you don't
get too close to the kiln, the color is the
same, but you get a lot less radiation.
Doesn't if fall off as the square of the
distance? I can see the color perfectly
well from across the room.
-Snail
David Berg on sat 21 jan 06
Regular clear glass and plexiglas blocks most of UV radiation but not
infrared. Therefore, you cannot get sunburned easily sitting in your
car behind the window glass but you can still feel the warmth from
the sun. Exception to the no sunburn in cars rule: convertibles ... ha!
Those of you who have the transition lenses in your glasses - the
kind that turn dark in the sun - know this to be true from
experience. The glasses will not turn nearly as dark in the car
because the window glass blocks the UV radiation that is required for
the reaction.
David T. Berg
http://bergstoneware.com
On Jan 20, 2006, at 4:18 PM, 2ley wrote:
> From: "Marcia Selsor"
>> Use goggles for UV protaction. Sorry but you can't judge color
>> through them very well.
>
> I wonder a bit at this. According to the manufacturer of my
> eyeglasses, I
> have 100% blocking of UV A and B. The lenses are not tinted. Is it
> possible to get untinted, but fully protective, goggles?
>
> Philip Tuley
>
> ______________________________________________________________________
> ________
> 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.
David Berg
dberg2@comcast.net
http://bergstoneware.com/
Paul Lewing on sat 21 jan 06
By the way, getting too close to hot peepholes will also warp your hard
contact lenses. This happened to my wife.
Paul Lewing, Seattle
Fredrick Paget on sat 21 jan 06
>
>
>
>Kilns put out very little UV radiation, but
>LOTS of IR radiation. Glassblower's goggles
>are untinted, and supposedly give a lot of
>protection. -Snail
Glass blowers goggles have dydimium lenses. ( A glass that
contains the rare earths neodymium and praseodymium. It has the
unique property of absorbing the yellow flare (Sodium line) that you
get when you heat sodium bearing glass to a melting temperature with
a torch.)
The yellow flare makes it hard to see what is going on. These goggles
offer a clear view of the hot glass. They are mainly used for so
called "lamp work" where the glass is melted in localized spots with
a torch.
Back when I was an engineer at Sylvania Lighting Products, I used a
pair of these so I could watch the glass blowers at work on the glass
lathes.
The plain dydimium lenses are not designed for welding and offer
little Infared protection. Sometimes they are used for brazing
because the flux has sodium in it and makes a lot of yellow flare.
Brazing is a lower temperature operation than welding so the IR is
less.
--
From Fred Paget,
Marin County, CA, USA
fredrick@well.com
http://homepage.mac.com/fredrick/FileSharing1.html
Charter Member Potters Council
Karen Latorre on sat 21 jan 06
>Glass blowers lenses mounted in a safety frame will completely block the
>IRspectrum. The ones I use are Didymium lenses. Got the lenses at a
>weldors' supply,
and glass blowing supply houses have them also.
Hank,
As I understand it (from a few years of hearing full time glassblowers
talk), Didymium lenses block the sodium flare that results from putting
glass into the path of a torch flame. It’s the orange/yellow “tail” that
develops from the glass in the direction away from the torch. When you put
the glasses on, the flare disappears. Lampworkers (the folks that make glass
beads and other items by exposing cold glass rods or tubes to a torch flame)
use these glasses, not glass blowers.
The difference between a glassblower and a lampworker is that in
lampworking, you are not exposed to the infrared that results from the
heated inside of a glass furnace. The furnace and glory hole radiate
infrared heat. They do not “flare”. Didymium, while it may provide a little
protection, will not protect you long term if you are blowing glass (or
staring into the inside of a kiln). You need welders’ #3 glass for that (as
others have already stated).
Also, when you look into the furnace or gloryhole with didymium glasses,
it’s hard to see the glass in there. With welder’s #3 on, you can see it
clear as day.
Karen, Belleville, Ontario
www.karenlatorre.com
- working on a web page of clay related pictures taken on my recent trip to
China. Fantastic trip. I will post when it’s done!
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