IR temperature measurement

[OMEEiron]

I am looking for a way to measure the temperature of my steel in the forge and wanted to see if anyone in the forums has experience with an IR temperature sensor.

 

In particular, this is the current listing on Amazon.com that I am considering:

 

http://www.amazon.com/Handheld-Non-Contact-Infrared-Thermometer-Targeting/dp/B007EYX0TS/ref=sr_1_17?s=hi&ie=UTF8&qid=1395934068&sr=1-17&keywords=high+temperature+type+k

 

The temperature measurement range is -58-3002F and also has a thermocouple input channel.

 

If anyone has experience with this unit, please let provide some feedback.

[clinton]

I have used a similar one less expensive and it works good on metal that is not shiny. If you grind or polish the metal it was not accurate

If you are pointing it in the forge I am not sure that will tell you how hot the metal is or how hot the forge is

[brianc]

I use those same guns at work and have wondered about checking steel temps as well. I know ours have to be adjusted for a certain emmisivity depending on the surface you are measuring. They will give a different reading if you shoot a black paint spot on an aluminum valve body vs the unpainted silver body right next to the spot. Maybe the newer temp guns dont have this error, ours are several years old.

 

Be curious to hear others comments

 

Brian

[timgunn1962]

The emissivity issue is pretty restrictive. It's fundamental physics, so the newer units are no better. The usual way of dealing with it is to shoot a workpiece at a known temperature, then adjust the emissivity setting until it reads correctly. As long as the emissivity of the workpiece doesn't change after that, the instrument will give accurate readings.

 

Because the thickness of the oxide layer changes the emissivity, it has limited value in "our" applications; soak at temperature and the Oxide layer gets thicker, hammer it and the oxide layer (scale) comes off.

 

I had a 1650 degC (2912 degF) IR unit and found it pretty close to useless. I passed it on to a smith who makes a lot of SanMai and Damascus. He seems to find it useful, though I think he uses it mainly to check that his billets are withinin the working temperature range, rather than for any sort of accurate measurement. I think he finds it "better" than judging by eye due to changing light levels in his shop.

 

My feeling is that buying/building a burner with good control of atmosphere/temperature and using a thermocouple/pyrometer to set it up, will give more repeatable results for less money. However, judging on the basis of the the work he produces, his method certainly seems to have something going for it. 

[gearhartironwerks]

Hi,
The point and shoot guns are not accurate in the forge. As such, I have and have used one. A thermocouple and a digital reader are much more accurate.
John

[the iron dwarf]

are there thermocouples that go high enough?

I melted one at 1980 degrees C before getting it into the middle of the fire and the forge was not even turned up very high

I know the IR ones would be flooded by the amount of IR produced

[rocketman]

Has anyone had any experience using a non contact infrared thermometer to harden steel?? 

How about tempering steel.

Seems like a good way to get a close to real time temperature, and the ranges of these 

devices are really good enough to use, but, how accurate are they in knife and blacksmithing.

Does anyone have a recommendation for emmisivity settings??

Looking forward to thoughts and advice.

Thanks

Bill