Kiln Temp verification

[KNelson]

hey folks, just curious as I’ve been thinking about it.. How do you all ensure your kiln is operating properly at the right temps? I have an older paragon 36D and am waiting for the day it needs maintenance..

Do you run a separate temperature probe? Use the firing cones or just rely on a newer controller?

The controller on my kiln is an older sentry and I bought the kiln of someone that knows nothing about knifemakeing so I know no history on it. It has been working great for me with good results though.

 

[Kevin McGovern]

I got one of these: https://www.amazon.com/Signstek-The...DCN0K5XXZFZ&psc=1&refRID=CH5DZCYVHDCN0K5XXZFZ

The main description is wrong, it goes up to over 2300 F. I also bought a K type probe thermocouple from aurberins. The same one my oven uses. I have an extra probe hole next to my primary one on my oven. I can double check the temp anytime. I also use this to make sure my tempering oven is correct, and when I grill a whole turkey.

 

[Keith Nix]

That^, and plain sodium chloride melts at 1474F.

 

[MBB]

Realistically, the actual temperature is not what you are controlling for. You're controlling for HRC. So the temperature is important but not critical. If you do a range of hardening temperatures with a set tempering temperature for a certain steel, you will end up with maximum hardness for your oven for that particular steel. For example, I did a range of AEB-L from 1900 to 1975 F in 25 degree steps, and found that 1975 F yielded max HRC for my oven.

If you do a range of different steels and find a trend where they all vary from established recipes in a certain direction (say 20 degrees off), then your oven is probably running hot/cold by that much.

This assumes that your oven temperatures are repeatable. If they're not, you have an entirely different problem and probably need to service either the probe or controller.

 

[KNelson]

Realistically, the actual temperature is not what you are controlling for. You're controlling for HRC. So the temperature is important but not critical. If you do a range of hardening temperatures with a set tempering temperature for a certain steel, you will end up with maximum hardness for your oven for that particular steel. For example, I did a range of AEB-L from 1900 to 1975 F in 25 degree steps, and found that 1975 F yielded max HRC for my oven.

If you do a range of different steels and find a trend where they all vary from established recipes in a certain direction (say 20 degrees off), then your oven is probably running hot/cold by that much.

This assumes that your oven temperatures are repeatable. If they're not, you have an entirely different problem and probably need to service either the probe or controller.

That’s a great point! I guess my biggest concern is the worry of my thermocouple going bad. Say, I set the oven for 1950 and assuming it’s at 1950 but in reality it’s only 1800.. I’m wondering a way like above, how to check to make sure the setting is what the temp is at.

 

[KNelson]

I got one of these: https://www.amazon.com/Signstek-Thermometer-58°F-1022°F-50-1300°C-Thermocouple/dp/B00FFYEPVQ/ref=pd_day0_hl_328_3/146-0675965-8810849?_encoding=UTF8&pd_rd_i=B00FFYEPVQ&pd_rd_r=5b832a24-1437-11e9-8a93-4f521d08b72b&pd_rd_w=JbrSq&pd_rd_wg=GfSn2&pf_rd_p=ad07871c-e646-4161-82c7-5ed0d4c85b07&pf_rd_r=CH5DZCYVHDCN0K5XXZFZ&psc=1&refRID=CH5DZCYVHDCN0K5XXZFZ

The main description is wrong, it goes up to over 2300 F. I also bought a K type probe thermocouple from aurberins. The same one my oven uses. I have an extra probe hole next to my primary one on my oven. I can double check the temp anytime. I also use this to make sure my tempering oven is correct, and when I grill a whole turkey.

Awesome thanks! The extra hole, do you plug it when not using it? Also does the TC plug right into the meter or did you have to wire it together?

 

[kc custom]

I have a friend that works for a fairly large electrical outfit. The first time he told me to set a temp I did, we let
it cycle at temp and then took a reading right next to the thermocouple. It was dead nuts "on". A year later he
was over one day and we did it again--same result. FLIR camera. I couldn't be happier for an oven with 20+
years on it.
Ken.

 

[KNelson]

I have a friend that works for a fairly large electrical outfit. The first time he told me to set a temp I did, we let
it cycle at temp and then took a reading right next to the thermocouple. It was dead nuts "on". A year later he
was over one day and we did it again--same result. FLIR camera. I couldn't be happier for an oven with 20+
years on it.
Ken.

Nice! My oven is from the 90’s so I’m hoping the same haha. I have a feeling mine is right on because a few blades I had hardness test done on when I first got the oven and it was spot on to what I was shooting for. According to some online recipes and what they said the hardness should be, is what I got also.

 

[Kevin McGovern]

Awesome thanks! The extra hole, do you plug it when not using it? Also does the TC plug right into the meter or did you have to wire it together?

I cover the hole with a brick.
It Plugs right in if you buy the thermocouple with the yellow plug .