Talbott on sat 17 jan 98
I always use an oxy-probe to tell me what my reduction rate is. In
a glaze fire I usually am firing for brillant metallic cobalt blues and
copper reds, etc. Prior to 800 Celsius I stay in oxidation. I usually go
into reduction around ^015 to ^010 and stay in reduction until ^9/10. The
oxyprobe reads around .55 from 800 Celsius thru 950 Celsius and then the
probe reading goes to .67 from 950 C until shut down at cone 9/10, which I
maintain by controlling the burner psi and the damper. On shut down I
close up the kiln tight and allow for a slow cool down.. usually 60 hrs
required for cooling prior to opening and unloading the kiln.
...Marshall
101 CLAYART MUGS (Summer 1998)
2ND ANNUAL CLAYARTERS' GALLERY - NAPLES, MAINE (Summer 1998)
E-MAIL ME FOR APPLICATIONS
http://fmc.utm.edu/~dmcbeth/cag/naples.htm
Celia & Marshall Talbott, Pottery By Celia, Route 114, P O Box 4116,
Naples, Maine 04055-4116,(207)693-6100 voice and fax,(call first)
Clayarters' Live Chat Room, Fri & Sat Nites at 10 PM EDT & Sun at 1 PM EDT
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---------------------------------------------------------------------
Dan Tarro on tue 29 jun 99
Marshall,
I have been saving old posts from Clay Art on the subject of O2 probes in
anticipation of going down that path soon. Well, I feel that I am at that
point now and would appreciate any help you could send my way on this
issue.
I have done some checking on a few of the probes that are on the market
and would like to know what you are using, how durable you feel it to be,
and if you think that there would be a better tool on the market rather
than the one you are using. If you could tell me about how many firings
you have seen so far with yours and how it is standing up to them with
depletion of life expectancy would be important.
I have seen the one that Axner is marketing (seen only in his ads) and
have compared to commercial ones sold to heat treaters and there seems to
be some big differences. If I am correct on these points what I found was
that the unit sold to us potters at a more reasonable rate has an alumina
tube with a zirconium plug(which is the actual sensing device) at the end
of it. The plug is glued to the tube with a type of high temp glue which
forms a weak spot for failure(air infiltration). The commercial probe is
a one piece, slip-cast tube with a dome end, all being of the same cast
made up of a zirconium alloy. Much the same way that the mulite sheaths
that we use around our thermocouples. The claim is that this does away
with the possible breach between reference air within the probe and the
air of the kiln, no seams.
Another difference I seem to be seeing is that the commercial units have
a reference air supply that is constantly being pumped into the interior
of the tube to refresh and give a more accurate reading. Do you know if
this is how those from Axner and other potter suppliers' operate? What I
have seen in ads is that no mention of air supply pumps are mentioned.
Price is a difference between the two types. Axners for the probe alone
will run $660 for a 12" where a 18" commercial probe from SSi out of
Cincinnati, OH runs about $1800.
Warranties, I talked with Jim from Axner and he said that he stood behind
his for 90 days. Expected to get at least 60 firing out of it before any
problems showed up if the tube was handled very carefully. SSi warranties
the high temp probes (3000 deg.) for six months. I would think that a
commercial probe that is installed in a batch furnace that was cycling 24
hours 365 days a year would be subjected to much more abuse than what a
studio potter would be doing.
What are your feelings?
Let me know, I will be looking forward to find out what your thoughts on
this are
Dan Tarro
Oak Tree Stoneware
Ham Lake, Mn.
On Sat, 17 Jan 1998 09:34:20 EST Talbott writes:
>----------------------------Original
>message----------------------------
> I always use an oxy-probe to tell me what my reduction rate
>is. In
>a glaze fire I usually am firing for brillant metallic cobalt blues
>and
>copper reds, etc. Prior to 800 Celsius I stay in oxidation. I
>usually go
>into reduction around ^015 to ^010 and stay in reduction until ^9/10.
>The
>oxyprobe reads around .55 from 800 Celsius thru 950 Celsius and then
>the
>probe reading goes to .67 from 950 C until shut down at cone 9/10,
>which I
>maintain by controlling the burner psi and the damper. On shut down
>I
>close up the kiln tight and allow for a slow cool down.. usually 60
>hrs
>required for cooling prior to opening and unloading the kiln.
> ...Marshall
>
> 101 CLAYART MUGS (Summer 1998)
> 2ND ANNUAL CLAYARTERS' GALLERY - NAPLES, MAINE (Summer
>1998)
> E-MAIL ME FOR APPLICATIONS
> http://fmc.utm.edu/~dmcbeth/cag/naples.htm
>
> Celia & Marshall Talbott, Pottery By Celia, Route 114, P O Box
>4116,
> Naples, Maine 04055-4116,(207)693-6100 voice and fax,(call
>first)
> Clayarters' Live Chat Room, Fri & Sat Nites at 10 PM EDT & Sun at 1
>PM EDT
> http://webchat12.wbs.net/webchat3.so?Room=PRIVATE_Clayarters
>
>---------------------------------------------------------------------
>
Dan Tarro
Oak Tree Stoneware
Ham Lake, Minnesota
___________________________________________________________________
Get the Internet just the way you want it.
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Nils Lou on wed 30 jun 99
One correction in your statement about the sensor "plug" in the potter's
version. It is not cemented in with high temp glue. The seal, which is not
a weak point, is created by eutectic welding--essentially fusing one
surface to the other. The "weak" point is actually the exterior platinum
wire which is weakened by successive firings becoming brittle. It is,
however, easily replaceable. If treated with care these probes can easily
handle 100 and more C10 reduction firings. At $660, not cheap, but for
some an indispensible tool. Watch for significant reductions in price from
Axner with an improved meter reading out directly in degrees centigrade
rather than mv needing to be converted. For those interested in digital
pyrometers, my sources say Axner will soon have one available for under
$65!
nils lou
On Tue, 29 Jun 1999, Dan Tarro wrote:
> ----------------------------Original message----------------------------
> Marshall,
>
> I have been saving old posts from Clay Art on the subject of O2 probes in
> anticipation of going down that path soon. Well, I feel that I am at that
> point now and would appreciate any help you could send my way on this
> issue.
>
> I have done some checking on a few of the probes that are on the market
> and would like to know what you are using, how durable you feel it to be,
> and if you think that there would be a better tool on the market rather
> than the one you are using. If you could tell me about how many firings
> you have seen so far with yours and how it is standing up to them with
> depletion of life expectancy would be important.
>
> I have seen the one that Axner is marketing (seen only in his ads) and
> have compared to commercial ones sold to heat treaters and there seems to
> be some big differences. If I am correct on these points what I found was
> that the unit sold to us potters at a more reasonable rate has an alumina
> tube with a zirconium plug(which is the actual sensing device) at the end
> of it. The plug is glued to the tube with a type of high temp glue which
> forms a weak spot for failure(air infiltration). The commercial probe is
> a one piece, slip-cast tube with a dome end, all being of the same cast
> made up of a zirconium alloy. Much the same way that the mulite sheaths
> that we use around our thermocouples. The claim is that this does away
> with the possible breach between reference air within the probe and the
> air of the kiln, no seams.
>
> Another difference I seem to be seeing is that the commercial units have
> a reference air supply that is constantly being pumped into the interior
> of the tube to refresh and give a more accurate reading. Do you know if
> this is how those from Axner and other potter suppliers' operate? What I
> have seen in ads is that no mention of air supply pumps are mentioned.
>
> Price is a difference between the two types. Axners for the probe alone
> will run $660 for a 12" where a 18" commercial probe from SSi out of
> Cincinnati, OH runs about $1800.
>
> Warranties, I talked with Jim from Axner and he said that he stood behind
> his for 90 days. Expected to get at least 60 firing out of it before any
> problems showed up if the tube was handled very carefully. SSi warranties
> the high temp probes (3000 deg.) for six months. I would think that a
> commercial probe that is installed in a batch furnace that was cycling 24
> hours 365 days a year would be subjected to much more abuse than what a
> studio potter would be doing.
>
> What are your feelings?
>
> Let me know, I will be looking forward to find out what your thoughts on
> this are
>
> Dan Tarro
> Oak Tree Stoneware
> Ham Lake, Mn.
> On Sat, 17 Jan 1998 09:34:20 EST Talbott writes:
> >----------------------------Original
> >message----------------------------
> > I always use an oxy-probe to tell me what my reduction rate
> >is. In
> >a glaze fire I usually am firing for brillant metallic cobalt blues
> >and
> >copper reds, etc. Prior to 800 Celsius I stay in oxidation. I
> >usually go
> >into reduction around ^015 to ^010 and stay in reduction until ^9/10.
> >The
> >oxyprobe reads around .55 from 800 Celsius thru 950 Celsius and then
> >the
> >probe reading goes to .67 from 950 C until shut down at cone 9/10,
> >which I
> >maintain by controlling the burner psi and the damper. On shut down
> >I
> >close up the kiln tight and allow for a slow cool down.. usually 60
> >hrs
> >required for cooling prior to opening and unloading the kiln.
> > ...Marshall
> >
> > 101 CLAYART MUGS (Summer 1998)
> > 2ND ANNUAL CLAYARTERS' GALLERY - NAPLES, MAINE (Summer
> >1998)
> > E-MAIL ME FOR APPLICATIONS
> > http://fmc.utm.edu/~dmcbeth/cag/naples.htm
> >
> > Celia & Marshall Talbott, Pottery By Celia, Route 114, P O Box
> >4116,
> > Naples, Maine 04055-4116,(207)693-6100 voice and fax,(call
> >first)
> > Clayarters' Live Chat Room, Fri & Sat Nites at 10 PM EDT & Sun at 1
> >PM EDT
> > http://webchat12.wbs.net/webchat3.so?Room=PRIVATE_Clayarters
> >
> >---------------------------------------------------------------------
> >
>
> Dan Tarro
> Oak Tree Stoneware
> Ham Lake, Minnesota
>
> ___________________________________________________________________
> Get the Internet just the way you want it.
> Free software, free e-mail, and free Internet access for a month!
> Try Juno Web: http://dl.www.juno.com/dynoget/tagj.
>
David Coggins on wed 30 jun 99
Dan,
If I may add my 2 cents worth here, I suggest that you look at
http://www.cof.com.au/dlprobe.htm http://www.cof.com.au/useoxy.htm and
http://www.cof.com.au/aicmeter.htm for all you need to know about the AIC
oxprobe.
I repair kilns and pyrometers, including some of these AIC oxyprobes (my
page is http://web.one.net.au/~dercoggins) and have never found any leakage
at the plug - this would be obvious because the platinum wires inside the
sheath would be affected by the reducing kiln atmosphere - none of the units
I have seen have had this problem.
There is one problem however with the oxyprobe. The connection to the
zirconia tip is made by a 0.5mm platinum wire down the outside the sheath.
This stretches during firing, and droops down. If disturbed when hot (eg.
the probe is moved for some reason) this wire can break. It is also subject
to decay from the reducing atmosphere in the kiln. Therefore, this wire will
need replacing from time to time, which is the only job I have ever done on
these probes - this is relatively easy, as a new piece of platinum wire can
be rewound around the zirconia plug and grafted onto the broken stub.
One way to reduce the above problem is to fit a pythagoras tube over the
sheath and platinum wire, with just the end showing out, in fact the
manufacturer offers this as an option.
The air supply to these units can be provided by a rubber bulb puffer, or a
small aquarium pump, connected to the small tube fitted to the head of the
thermocouple. In practice, users of these units have reported little
difference in atmosphere readings whether there is fresh air pumped in or
not! Purists may still prefer to fit a pump.
Regards
Dave
David & Elaine Coggins
dercoggins@one.net.au
http://web.one.net.au/~dercoggins
-----Original Message-----
From: Dan Tarro
To: CLAYART@LSV.UKY.EDU
Date: Tuesday, 29 June 1999 11:27
Subject: Re: Reduction and Oxy-probes
>----------------------------Original message----------------------------
>Marshall,
>
>I have been saving old posts from Clay Art on the subject of O2 probes in
>anticipation of going down that path soon. Well, I feel that I am at that
>point now and would appreciate any help you could send my way on this
>issue.
>
>I have done some checking on a few of the probes that are on the market
>and would like to know what you are using, how durable you feel it to be,
>and if you think that there would be a better tool on the market rather
>than the one you are using. If you could tell me about how many firings
>you have seen so far with yours and how it is standing up to them with
>depletion of life expectancy would be important.
>
>I have seen the one that Axner is marketing (seen only in his ads) and
>have compared to commercial ones sold to heat treaters and there seems to
>be some big differences. If I am correct on these points what I found was
>that the unit sold to us potters at a more reasonable rate has an alumina
>tube with a zirconium plug(which is the actual sensing device) at the end
>of it. The plug is glued to the tube with a type of high temp glue which
>forms a weak spot for failure(air infiltration). The commercial probe is
>a one piece, slip-cast tube with a dome end, all being of the same cast
>made up of a zirconium alloy. Much the same way that the mulite sheaths
>that we use around our thermocouples. The claim is that this does away
>with the possible breach between reference air within the probe and the
>air of the kiln, no seams.
>
>Another difference I seem to be seeing is that the commercial units have
>a reference air supply that is constantly being pumped into the interior
>of the tube to refresh and give a more accurate reading. Do you know if
>this is how those from Axner and other potter suppliers' operate? What I
>have seen in ads is that no mention of air supply pumps are mentioned.
>
>Price is a difference between the two types. Axners for the probe alone
>will run $660 for a 12" where a 18" commercial probe from SSi out of
>Cincinnati, OH runs about $1800.
>
>Warranties, I talked with Jim from Axner and he said that he stood behind
>his for 90 days. Expected to get at least 60 firing out of it before any
>problems showed up if the tube was handled very carefully. SSi warranties
>the high temp probes (3000 deg.) for six months. I would think that a
>commercial probe that is installed in a batch furnace that was cycling 24
>hours 365 days a year would be subjected to much more abuse than what a
>studio potter would be doing.
>
>What are your feelings?
>
>Let me know, I will be looking forward to find out what your thoughts on
>this are
>
>Dan Tarro
>Oak Tree Stoneware
>Ham Lake, Mn.
>On Sat, 17 Jan 1998 09:34:20 EST Talbott writes:
>>----------------------------Original
>>message----------------------------
>> I always use an oxy-probe to tell me what my reduction rate
>>is. In
>>a glaze fire I usually am firing for brillant metallic cobalt blues
>>and
>>copper reds, etc. Prior to 800 Celsius I stay in oxidation. I
>>usually go
>>into reduction around ^015 to ^010 and stay in reduction until ^9/10.
>>The
>>oxyprobe reads around .55 from 800 Celsius thru 950 Celsius and then
>>the
>>probe reading goes to .67 from 950 C until shut down at cone 9/10,
>>which I
>>maintain by controlling the burner psi and the damper. On shut down
>>I
>>close up the kiln tight and allow for a slow cool down.. usually 60
>>hrs
>>required for cooling prior to opening and unloading the kiln.
>> ...Marshall
>>
>> 101 CLAYART MUGS (Summer 1998)
>> 2ND ANNUAL CLAYARTERS' GALLERY - NAPLES, MAINE (Summer
>>1998)
>> E-MAIL ME FOR APPLICATIONS
>> http://fmc.utm.edu/~dmcbeth/cag/naples.htm
>>
>> Celia & Marshall Talbott, Pottery By Celia, Route 114, P O Box
>>4116,
>> Naples, Maine 04055-4116,(207)693-6100 voice and fax,(call
>>first)
>> Clayarters' Live Chat Room, Fri & Sat Nites at 10 PM EDT & Sun at 1
>>PM EDT
>> http://webchat12.wbs.net/webchat3.so?Room=PRIVATE_Clayarters
>>
>>---------------------------------------------------------------------
>>
>
>Dan Tarro
>Oak Tree Stoneware
>Ham Lake, Minnesota
>
>___________________________________________________________________
>Get the Internet just the way you want it.
>Free software, free e-mail, and free Internet access for a month!
>Try Juno Web: http://dl.www.juno.com/dynoget/tagj.
Gary Hill on wed 30 jun 99
At 09:27 AM 6/29/99 EDT, you wrote:
>----------------------------Original message----------------------------
>Marshall,
>........I have done some checking on a few of the probes that are on the
market
>and would like to know what you are using, how durable you feel it to be,
>and if you think that there would be a better tool on the market rather
>than the one you are using. If you could tell me about how many firings
>you have seen so far with yours and how it is standing up to them with
>depletion of life expectancy would be important.
I use an oxy probe and find it a great help in conserving fuel and
repeating firings, (most critical for research). For some good information
on probes suitable for potters have a look at http://www.cof.com.au/aos.htm .
Yes you do need to supply air to the probe, I do this by hooking up a fish
tank air pump to the tube from the probe, saves manually pumping. I find
that glaze build up (from vapours) over the tip reduces its efectivness and
is far more of a problem than the adheasive failing. Price for a 300mm
probe is around A$400 ex factory which is a lot less than US$. They
probably have a distributor in the US. One very good point with the
technology used is that the output is in Mv and can be read with a quality
multimetre. There are tables to convert the readings to somthing meaningfull.
Hope this is of some help
Regards
Gary R Hill
g.hill@bendigo.latrobe.edu.au
Ingeborg Foco on thu 1 jul 99
I have had an oxy probe for a number of years and purchased it from Nils Lou
in Oregon. It was made by Architectural & Industrial cermics PTY.LTDin
Australia.I have fired it in reduction ^l0 for at least 75 times. I am very
careful with it and basically remove it from the kiln after the firing (not
moving it around to other locations during the firing which might give more
realistic readings) I had Nils glue on a protective sheath (additional cost)
so only the end is exposed. So far I've not had any problems. I sincerely
hope talking about it doesn't create a problem.
It has been helpful and then on the other hand not!
There are times the probe readings indicate that I will have exquisite reds
beyond my expectations...only to find out that is not the case (The entire
reason I purchased the tool) Other times the indications and results are
reversed.
In general, It gives me something to follow in attempting to emulate a good
firing. I have had better luck with reds and my fuel consumption is pretty
close for each firing. I still go by the other signs i.e. type of flame from
peeps and smell. What the probe did teach me was that black belching smoke
does not necessarily create beautiful red pots. Generally the opposite is
true.
Could I fire without the probe? Yes. Would I like to? Probably not. Is it
worth all of the money? I don"t know. Many other factors come into play
when using the probe the temperature of the day, the type of day..sunny or
rainy windy or calm and so forth. I dea lwith alot of wind and it can play
havoc with reduction firings and the probe will tell you.
It is a nice tool to have but is just that..another tool
Hope my two cents were of some help.
Ingeborg (Pacific NorthWest)
John K Dellow on fri 2 jul 99
>
> In general, It gives me something to follow in attempting to emulate a good
> firing. I have had better luck with reds and my fuel consumption is pretty
> close for each firing. I still go by the other signs i.e. type of flame from
> peeps and smell. What the probe did teach me was that black belching smoke
> does not necessarily create beautiful red pots. Generally the opposite is
> true.
>
> Could I fire without the probe? Yes. Would I like to? Probably not. Is it
> worth all of the money? I don"t know. Many other factors come into play
> when using the probe the temperature of the day, the type of day..sunny or
> rainy windy or calm and so forth. I dea lwith alot of wind and it can play
> havoc with reduction firings and the probe will tell you.
>
> It is a nice tool to have but is just that..another tool
>
> Hope my two cents were of some help.
>
> Ingeborg (Pacific NorthWest)
--
Its worth mentioning that on a hot hot dry day the amount of oxygen
per cu.cm of air is less than on a cold wet day. Hence one will need to
reduce less on the hot day day as opposed to the cold wet day
I also have a barometer and hydrometer near my kiln to use as a
reference when firing.
John Dellow "the flower pot man"
ICQ : #2193986 {jacka}
E-mail : dellowjk@kewl.com.au
25 Hugh Guinea Ct, Worongary Q 4213
Ph:+61-7-55302875 Fax:+61-7-55253585
Home Page http://www.welcome.to/jkdellow
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