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Infrared thermometer instead of thermocouples for manual kiln?


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I have an old manual L&L kiln that has an analog pyrometer, 3 thermocouples attached to a central gauge, which recently pooped out on me. I came to realize that I don't need to have them in at all times, since I only need to check the temperatures occasionally in order to turn the switches up or down. They were never really accurate anyway, since I could fiddle with the dial and the needle would fluctuate wildly, but gave me a general sense of where the kiln was. 

At first I looked for a digital version of the thing I was using, but then since I couldn't  find one, I thought that I may not even need that. From what I'm reading, they shouldn't stay in all the time anyway if they're not connected to the control panel, right? And then I won't have little piles of flaky black crust landing on my shelves. So in looking for a pyrometer that I could just insert into the 3 zones, get the readings and remove it, I saw an infrared thermometer that goes well beyond the temperature I'd need. Does anyone use something like this to measure inside your kiln up to cone 6? Is a regular digital pyrometer with a thermocouple better? I just want to have a way to see where I am with my firing, to know when to turn up the settings and watch for cones to start dropping. I'm not doing anything fancy at all with my glazing, and with bisque I pretty much turn the dials at set times and then let the kiln sitter drop on its own. 

I plan to get a new kiln at some point in the future, and relegate this to bisque only, so this doesn't need to be an expensive or high tech option!

https://www.amazon.com/Infrared-Thermometer-Non-Contact-Flashlight-Temperature/dp/B079HHSHLQ/ref=sr_1_4?dchild=1&keywords=digital%2Bceramic%2Bpyrometer&qid=1584029731&s=hi&sr=1-4&th=1

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I think part of the problem with using the IR thermometers is that they're hard to focus in through a kiln peephole. It's a small hole, so you'd have to be pretty close to it to keep it from reading the surface of the kiln around the hole.

Analog pyrometers are terrible. If you want to track track of climb over a period of a few minutes or do manual holds, they're pretty much worthless. Get an inexpensive digital pyrometer and you'll be much happier. If your thermocouples are shedding, put them in protection tubes.

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Thanks, I think I won't go for an infrared then. As to the thermocouple flaking, I was thinking that I'd just insert the thermocouple in the peep holes when I wanted to get a reading, instead of leaving it in all the time. That would help slow down its decomposing and it wouldn't flake so much, I hope.

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So then I'd need to find a pyrometer that reads 3 thermocouples at a time, right? So far it looks like they do 2 at a time at most. Or would I just leave one dangling while I'm reading the others? 

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Just leave them in. The repeated rapid heating and cooling isn't necessarily good for them. Protection tubes are worth every dime.

I'd just use two thermocouple unless you're doing some fancy work with the switches to do a soak or something like that. Even then, if you put them at the junctions of the rings you'd be way more accurate compared to having just one. If they're just there to see approximate temp or rate of climb, there's no need for 3.

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Okay, that makes sense. I guess I will put them in the bottom and middle rings where they already were, since the top ring is closer to what the middle ring usually is and the bottom runs cooler. Thanks for your help with this.

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34 minutes ago, kswan said:

Okay, that makes sense. I guess I will put them in the bottom and middle rings where they already were, since the top ring is closer to what the middle ring usually is and the bottom runs cooler. Thanks for your help with this.

You could always use an economical display with as many channels as you like and budget allows. The cool thing about thermocouples is they are fairly precise by definition so you can find relatively inexpensive displays that are reasonably accurate. 
 

Just another option.

 

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Edited by Bill Kielb
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I wonder how to tell how well something like that is going to work, though.  Are there any brands of pyrometers that measure at least 2 at a time you're familiar with that you'd trust? Or does it come down more to how reliable the thermocouple itself is? I'd always rather get something I think will be more reliable!

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43 minutes ago, kswan said:

I wonder how to tell how well something like that is going to work, though.  Are there any brands of pyrometers that measure at least 2 at a time you're familiar with that you'd trust? Or does it come down more to how reliable the thermocouple itself is? I'd always rather get something I think will be more reliable!

Thermo couples are calibrated in mv output. Every thermocouple is basically self calibrating and puts out an exact voltage at a given temperature. Are they perfect? No, but usually very close . The circuits used to read them these days are on a chip complete with what’s called cold junction compensation, etc.  The discrete components surrounding them are probably common tolerance instead of high tolerance. In all likelihood for ceramics kiln use it’s probably fine. A common way to check ANY pyrometer is to swap thermocouples during observation and look for large differences.. 

There are many of these units at varying prices and of course NIST certified units at ten times the cost. Like voltmeters,  not many need a certified one, and even the cheap ones are reasonable for most ordinary use. Google K type thermocouple and look at the table. Basically you could do the same thing with a 4 channel voltmeter and a table in hand. Of course most people don’t have certified voltmeters.

My guess, it’s likely fine for Kiln work. Swap inputs around and see the difference if you suspect it’s way off.

Edited by Bill Kielb
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  • 3 weeks later...

IR thermometer is really hard to focus on through a kiln peephole but it is still possible.

When I was choosing my own one (ennoLogic eT1050D), I relied on features such as accuracy and distance spot ratio. These features play for me the main role when I choose the IR unit. In fact, mine has +-1% accuracy (it is cool for IR thermometers) and a 10:1 distance spot ratio, and this is pretty good for my works. In this article, it takes 2nd place but I'd give it the first one.

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1 hour ago, Dalectia said:

IR thermometer is really hard to focus on through a kiln peephole but it is still possible.

When I was choosing my own one (ennoLogic eT1050D), I relied on features such as accuracy and distance spot ratio. These features play for me the main role when I choose the IR unit. In fact, mine has +-1% accuracy (it is cool for IR thermometers) and a 10:1 distance spot ratio, and this is pretty good for my works. In this article, it takes 2nd place but I'd give it the first one.

It only measures to cone 05, so not particularly useful unless you're low firing

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1 hour ago, liambesaw said:

It only measures to cone 05, so not particularly useful unless you're low firing

The recommended (Editors choice) one has a precision of 2% and goes beyond cone ten  and is 30:1 and is  a bit cheaper as well than ennologic IRT. On the other hand K thermocouples are just handy, accurate  and cheap. Pretty amazing actually.

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I'm actually using a digital pyrometer right now, giving it a test run. It has 2 inputs but unfortunately I only received one cable so I've got it in the middle ring section. I think an IR thermometer could come in handy in other situations though, like checking the temperature of your lid or rings for leaks, vent piping, sick people... :)

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52 minutes ago, kswan said:

I'm actually using a digital pyrometer right now, giving it a test run. It has 2 inputs but unfortunately I only received one cable so I've got it in the middle ring section. I think an IR thermometer could come in handy in other situations though, like checking the temperature of your lid or rings for leaks, vent piping, sick people... :)

IR definitely work well in other situations. I keep one in my tool kit for testing relays and outlets that may be overheating. I also know a lot of people who use them for cooking

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I have a few of these IR thermometers myself -mainly for trailer bearings on the boat axles while towing-good for spot checks but as Neil said a fixed gauge is so easy to read just using your eyes . no need to hold up or put away anything.

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Ok, but it's a cone measuring the temperature of the bowl.

I want the IR and the 4way, and the ice cream.

Mine is good until 1000F, and it pretty accurate in the peep.

Cat people just gotta be careful they don't send the cat jumping into the kiln.

Sorce

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