Michael juengling on sat 2 aug 03
I recently purchased a pyrometer with the K type thermocouple and a
protective ceramic cover. My question is what is the best method of
mounting the thermocouple in the kiln. I have a Skutt 1027 kiln which has a
spot in the side where a hole in the metal jacket has been left for this for
this purpose. However, the hole is too small to accommodate the ceramic
cover. I considered using a peephole but they are too wide at the outside
and too narrow on the inside. I am also wondering at the best way to drill
and cut the insulating brick. Any help would be much appreciated.
Thanks,
Mike J.
Hollis Engley on sat 2 aug 03
I'd appreciate the same information as Michael Juengling. My Olympic DD17
was ordered with an analog pyro, but no particular place to put it. Was
considering the upper right rear spot, which seemed reasonable to me, though
I'm not sure why. Will have to drill through galvanized steel and the
ceramic fiber to insert it. Now, after the recent thread about digital
pyros, I'm considering just buying one and not using the other.
Hollis Engley
Hatchville Pottery
Falmouth, Mass.
hengley@cape.com
John Rodgers on sat 2 aug 03
I just got a new analog pyrometer with K-type thermocouple and ceramic
cover and was faced with the same situation. Hole was too small.
My thermocouple cover was too long and had to be shortened, so I used a
dremel tool to cut it off. Then I took the short piece that I cut off
and ground it to a bit of a chisel point. Being that the cover is a
tube, that made a couple of teeth on the end of the tube so that I had
what was like a hollow ceramic drill bit. I pressed that into the brick
on the inside of the kiln into the existing hole, rotating it by hand at
the same time. I kept turning it, pulling it back every now and then to
brush and blow out the brick particles. In a while, the "Drill Bit"
contacted the staninless kiln cover and the hole was done. I then used a
dremel tool and a grinding bit to open up the hole in the stainless
jacket for a tight fit for the homemade ceramic bit. I then turned the
bit a little more pushing it out through the stainles jacket. The hole
was done. It was a nice, very close fit for the ceramic cover tube, and
it works great.
The only thing I have found different with the new pyrometer is that my
temperature vs cone drop are off. Pyrometer reads 150 degrees low when
the 06 cone goes down, and about 50 degrees low when the 5 cone goes
down. Not a real biggie, since I have now noted the differences, but a
bit of a PITA because I have to watch it closer.
Regards,
John Rodgers
Birmingham, AL
Michael juengling wrote:
>I recently purchased a pyrometer with the K type thermocouple and a
>protective ceramic cover. My question is what is the best method of
>mounting the thermocouple in the kiln. I have a Skutt 1027 kiln which has a
>spot in the side where a hole in the metal jacket has been left for this for
>this purpose. However, the hole is too small to accommodate the ceramic
>cover. I considered using a peephole but they are too wide at the outside
>and too narrow on the inside. I am also wondering at the best way to drill
>and cut the insulating brick. Any help would be much appreciated.
>
>Thanks,
>Mike J.
>
>______________________________________________________________________________
>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.
>
>
>
Michael juengling on sun 3 aug 03
Thanks for the reply. That's a great idea using the tube for a drill bit.
Again my situation is similar in that the tube is too long for the
thermocouple. I will try using the leftover. Thanks again.
Mike Juengling
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of John Rodgers
Sent: Saturday, August 02, 2003 6:28 PM
To: CLAYART@LSV.CERAMICS.ORG
Subject: Re: Another Pyrometer Question
Bill Buckner on sun 3 aug 03
Mike,
You probably do not need the porcelain protective tube for the thermocouple
in an electric kiln. There is no atmosphere (reduction, salt, etc.) from
which to protect the thermocouple. Simply drill the proper size hole
(1/2", perhaps?) through the hole provided in the stainless steel jacket
(DO THIS WITH THE KILN POWER DISCONNECTED, OF COURSE!). Just leave space
as you load the kiln for the thermocouple to be inserted into the kiln
interior 3-4" without touching anything. Removing the thermocouple at the
conclusion of the fire seems to prolong its life.
-Bill
Atlanta
At 09:06 AM 8/2/2003 -0400, you wrote:
>I recently purchased a pyrometer with the K type thermocouple and a
>protective ceramic cover. My question is what is the best method of
>mounting the thermocouple in the kiln. I have a Skutt 1027 kiln which has a
>spot in the side where a hole in the metal jacket has been left for this for
>this purpose. However, the hole is too small to accommodate the ceramic
>cover. I considered using a peephole but they are too wide at the outside
>and too narrow on the inside. I am also wondering at the best way to drill
>and cut the insulating brick. Any help would be much appreciated.
>
>Thanks,
>Mike J.
billBUCKNER
www.sodaglaze.com
Life is too important to be taken seriously.
-Oscar Wilde
Cindi Anderson on sun 3 aug 03
Need? No. But the thermocouples will last longer in protection tubes.
Here is some data from testing L&L did. They were able to do 139 Cone 10
firings with the protection tube compared to 100 firings without. There is
still carbon and sulfur coming out of clay even when fired at oxidation.
The other info about the temperature lag is interesting too.
http://www.hotkilns.com/tc-protect.pdf
Cindi
----- Original Message -----
From: "Bill Buckner"
To:
Sent: Sunday, August 03, 2003 7:27 AM
Subject: Re: Another Pyrometer Question
> Mike,
>
> You probably do not need the porcelain protective tube for the
thermocouple
> in an electric kiln. There is no atmosphere (reduction, salt, etc.) from
> which to protect the thermocouple. Simply drill the proper size hole
> (1/2", perhaps?) through the hole provided in the stainless steel jacket
> (DO THIS WITH THE KILN POWER DISCONNECTED, OF COURSE!). Just leave space
> as you load the kiln for the thermocouple to be inserted into the kiln
> interior 3-4" without touching anything. Removing the thermocouple at the
> conclusion of the fire seems to prolong its life.
>
> -Bill
> Atlanta
>
> At 09:06 AM 8/2/2003 -0400, you wrote:
> >I recently purchased a pyrometer with the K type thermocouple and a
> >protective ceramic cover. My question is what is the best method of
> >mounting the thermocouple in the kiln. I have a Skutt 1027 kiln which
has a
> >spot in the side where a hole in the metal jacket has been left for this
for
> >this purpose. However, the hole is too small to accommodate the ceramic
> >cover. I considered using a peephole but they are too wide at the
outside
> >and too narrow on the inside. I am also wondering at the best way to
drill
> >and cut the insulating brick. Any help would be much appreciated.
> >
> >Thanks,
> >Mike J.
>
> billBUCKNER
> www.sodaglaze.com
>
> Life is too important to be taken seriously.
> -Oscar Wilde
>
>
____________________________________________________________________________
__
> 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 harrison on sun 3 aug 03
Hi Mike J,
You can drill the soft firebrick with any kind of drill, even a wood
drill bit will do. the brick is very soft.
alternatively you might file it out with a round file.
regards
Steve Harrison
On Saturday, August 2, 2003, at 11:06 PM, Michael juengling wrote:
> I recently purchased a pyrometer with the K type thermocouple
> I am also wondering at the best way to drill
> and cut the insulating brick.
> Mike J.
>
karen gringhuis on sun 3 aug 03
To Michael and Hollis -
As Rogers and Harrison have said, drilling thru the
kiln side is not that big a deal - but yes, I DID have
a pro do it for me.
BUT BEFORE YOU DO THAT, Michael, you with the Skutt &
small hole already open....read on.
My L & L had only the small hole imprint on the metal
shell which I had drilled out. Only later did I get
the ceramic cover for the probe which, yes was too lg.
for small hole. So I had about 4 - 6" of the TIP of
the cover cut off and I simply use it INSIDE the kiln
covering only the tip of the probe which is inside the
kiln. This leaves the back end of the naked probe
still fitting through the small hole, no enlargement
needed.
Please forgive this analogy but it's very clear: the
chopped off cover works exactly like a condom on the
business end of the probe - and that is why I got the
cover - because as the metal tip of the probe
oxidized/degraded, it shed tiny metal bits which I
thought were falling onto glazed pots. I had the cover
cut by a pro I think with a brick saw.
Even with a cover, I replace the probe every so often
for this reason.
Hope this helps.
=====
Karen Gringhuis
KG Pottery
Box 607 Alfred NY 14802
__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
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Bill Buckner on sun 3 aug 03
Okay. L&L is in the *business* of *selling* those porcelain tubes. So, is
that reliable data? Or, is it marketing hype? Generally, those porcelain
tubes cost about as much as a thermocouple. If you put your money into two
thermocouples instead of a thermocouple and a tube, you could get 200
firings instead of 139 for the same price (based on the L&L data)!
Don't get me wrong. I use those tubes in my reduction and soda
kilns. But, not in the electric. And I have nothing against L&L. I used
to own one of their kilns. But, I don't bite at everything that is offered
to me in a magazine or on the Web, either!
-Bill Buckner
Atlanta
At 11:39 AM 8/3/2003 -0700, you wrote:
>Need? No. But the thermocouples will last longer in protection tubes.
>Here is some data from testing L&L did. They were able to do 139 Cone 10
>firings with the protection tube compared to 100 firings without. There is
>still carbon and sulfur coming out of clay even when fired at oxidation.
>The other info about the temperature lag is interesting too.
>http://www.hotkilns.com/tc-protect.pdf
>
>Cindi
billBUCKNER
www.sodaglaze.com
Life is too important to be taken seriously.
-Oscar Wilde
Bill Buckner on sun 3 aug 03
The devil's advocate here, again!
Let's think about this one, too. The porcelain tube covers the end of the
pyrometer. But, the porcelain tube ends INSIDE the kiln. Ergo, the
interior of the porcelain tube contains the same atmosphere as that INSIDE
the kiln. And so is the thermocouple since it is inside the tube. To use
your analogy, isn't this a bit like pushing the condom in ahead of the
"probe" instead of actually wearing it?
So, how is this protecting the thermocouple??
-Bill Buckner
Atlanta
At 02:45 PM 8/3/2003 -0700, you wrote:
>To Michael and Hollis -
>
>As Rogers and Harrison have said, drilling thru the
>kiln side is not that big a deal - but yes, I DID have
>a pro do it for me.
>
>BUT BEFORE YOU DO THAT, Michael, you with the Skutt &
>small hole already open....read on.
>
>My L & L had only the small hole imprint on the metal
>shell which I had drilled out. Only later did I get
>the ceramic cover for the probe which, yes was too lg.
>for small hole. So I had about 4 - 6" of the TIP of
>the cover cut off and I simply use it INSIDE the kiln
>covering only the tip of the probe which is inside the
>kiln. This leaves the back end of the naked probe
>still fitting through the small hole, no enlargement
>needed.
>
>Please forgive this analogy but it's very clear: the
>chopped off cover works exactly like a condom on the
>business end of the probe - and that is why I got the
>cover - because as the metal tip of the probe
>oxidized/degraded, it shed tiny metal bits which I
>thought were falling onto glazed pots. I had the cover
>cut by a pro I think with a brick saw.
>
>Even with a cover, I replace the probe every so often
>for this reason.
>
>Hope this helps.
billBUCKNER
www.sodaglaze.com
Life is too important to be taken seriously.
-Oscar Wilde
Edouard Bastarache on sun 3 aug 03
Hello all,
So says Smart:
"Pour un four cuisant toujours en oxydation (sans jamais faire d'effets
réducteurs. Ex : fours à faïence ou fours électriques en général) vous
pouvez utiliser votre thermocouple à nu sans canne pyrométrique. Cela vous
permet de vérifier visuellement l'état de la soudure chaude à chaque
enfournement et aussi de limiter l'inertie due à la canne pyrométrique pour
faciliter un pilotage en douceur de votre four. C'est aussi bien moins
encombrant. L'exposition nue du thermocouple dans ces conditions ne le
fragilise aucunement (Sauf en cas de forte réduction : le platine se
volatilise !!)."
In oxidation you may use naked thermocouples i.e. without a protection tube;
it is actually an asset because you may check its integrity before each
firing.( the state of the welded spot) and it reacts more rapidly to changes
in temperature to allow smoother firings, because of the elimination of the
inertia caused by the protection tube.
In the case of strong reduction platinium will volatize so, then you need
the protection tube.
For those who understand french, here is how to repair a broken
thermocouple:
http://perso.wanadoo.fr/smart2000/reparer_thermocouple_casse.htm
Later,
"Ils sont fous ces Quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
Alex Solla on mon 4 aug 03
Couple of questions:
Where did you get the sleeves? Seeing as how you dont need them to be very long, how much do you have exposed inside the kiln? Did you cement it to the soft brick?
How many firings are you getting on the pyrometer thermocouple? Does the sleeve distort the temperature readings much?
Thanks!
Alexander Solla
Cold Springs Studio
4088 Cold Springs Road
Trumansburg, NY 14886
karen gringhuis wrote:
To Michael and Hollis -
As Rogers and Harrison have said, drilling thru the
kiln side is not that big a deal - but yes, I DID have
a pro do it for me.
BUT BEFORE YOU DO THAT, Michael, you with the Skutt &
small hole already open....read on.
My L & L had only the small hole imprint on the metal
shell which I had drilled out. Only later did I get
the ceramic cover for the probe which, yes was too lg.
for small hole. So I had about 4 - 6" of the TIP of
the cover cut off and I simply use it INSIDE the kiln
covering only the tip of the probe which is inside the
kiln. This leaves the back end of the naked probe
still fitting through the small hole, no enlargement
needed.
Please forgive this analogy but it's very clear: the
chopped off cover works exactly like a condom on the
business end of the probe - and that is why I got the
cover - because as the metal tip of the probe
oxidized/degraded, it shed tiny metal bits which I
thought were falling onto glazed pots. I had the cover
cut by a pro I think with a brick saw.
Even with a cover, I replace the probe every so often
for this reason.
Hope this helps.
=====
Karen Gringhuis
KG Pottery
Box 607 Alfred NY 14802
__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
http://sitebuilder.yahoo.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.
---------------------------------
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
John Baymore on mon 4 aug 03
Bill,
Let's think about this one, too. The porcelain tube covers the end of th=
e
pyrometer. But, the porcelain tube ends INSIDE the kiln. Ergo, the
interior of the porcelain tube contains the same atmosphere as that INSID=
E
the kiln. And so is the thermocouple since it is inside the tube. =
In an electric kiln the atmosphere is not necessarily oxidising. Or
neutral for that matter. The atmosphere can vary all over the place
depending on what is being fired, and how it is being fired, if there is =
a
local pickup kiln vent, and so on. In a bisque, there may be periods of=
reduction. Gases such as oxides of sulphur or stuff like florine are oft=
en
given off. Additionally, in a glaze firing there are traces of many if n=
ot
most of the constituients of the glazes in the atmosphere. All this stuf=
f
can impact the exposed metal of the thermocouple probe. As the metal of
the probe is "changed"....... the signal it generates is changed. So the=
temperature reading slowly changes with use. =
In much of ceramic industry, thermocouples are periodically tested and th=
e
readings on the display devices (usually computers these days) are
calibrated. They know the "passband" of degredation at which point a
thermocouple is considered "shot".......... meaning the reading is gettin=
g
outside the acceptable accuracy range. It gets pulled and a new one goes=
in. Does it still "give a reading"? Yes. But not an accurate enough
reading. =
This is a quite different =
approach from what most handcraft potters use. We tend to use them until=
they just stop sending ANY signal ....... just burn out . Our
tolerances are often wider so we can sort of get away with it. (Sometime=
s
they are not...... but we don't typically KNOW that...and then have some
problems as a result .) Sometime all we really use them for is to kno=
w
if the kiln is still getting hotter . During that long slow path to
thermocouple burn out.... the readings typically get progressively furthe=
r
and further off.
The "porcelain" tube is basically gas impermeable to the stuff that might=
impact the life of the thermocouple. Since the rear end is outside the
kiln and is open to the air.... the gases in it are basically air. So th=
e
thermocouple sees pretty much a constant oxidising condition. So the
exterior of the thermocouple forms a little layer of metal oxide........
similar to the concept about those on kiln elements. This tends to slow
down further oxidation to the layers underneath and keeps degredation to =
a
minimum. And within the tube .......... it does not get impacted by the
other stuff in the kiln atmosphere either. The protection tube might
eventually get a little "vapor glazed" by volatilizing glaze materials
.......... but these do not get thru the tube wall to the thermocouple.
One down side to the protection tubes is that they induce a longer lag in=
response time to what is actually going on in the chamber. The transfer =
of
heat thru the tube to the thermocouple takes a little time. Until the
situation in the chamber reaches stasis...... the thermocouple will likel=
y
always be a tad behind the chamber. This lag factor is also true of real=
ly
thick thermocouples compared to really thin ones..... the mass of the
thermocouple has to be heated. If fast response is what you want....then=
you trade it for some thermocouple life. In my noborigama I usually use
pretty thin thermocouples and leave them completely exposed. Yes.......
they die fast. But they give me fast response and they are cheap relativ=
e
to the volume and value of wares being fired.
You have a bit of a point about looking at the cost effectiveness. If th=
e
cost to protect the thermocouple to extend the life by say 50 % is the sa=
me
as the cost to replace the thermocouple and get 100 more "life"..... then=
it makes more sense to just replace the thermocouple. However, this idea=
does not take into account that as the thermocouple deteriorates over tim=
e,
unless you recalibrate (which most potters do not have the tools to do),
the readings that you are getting degrade. IF... and that is a big
"if"....... you need information that is really accurate as far as
temperature readings go, then extending the "life" of the original
thermocouple is a desireable goal. Other wise you'd have to replce the
thermocouple more often. If you just want to know if you are increasing,=
decreasing, or holding temperature.... then it pretty much matters not wh=
at
the actual temperature readings say.
best,
........................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086-5812 USA
JBaymore@compuserve.com
http://www.JohnBaymore.com
603-654-2752 (studio)
800-900-1110 (studio)
"Earth, Water, and Fire Noborigama Woodfiring Workshop: August 15-24,
2003"
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