Temp guns

[CyFi6]

Im in the seach for an infrared temp gun recently, looking to buy one. The only ones i have used have been Raytek and they seem to work great, but i was wondering if anyone else had any other ones or even if they have a raytek, what do you think of it? I see some of the smaller raytek guns for selling under 50 dollars, iw as wondering how those perform? THanks for the help.

 

[IJ.]

I have a RayTek, you need to get a straight shot at right angles to the surface or the reading can be quite a bit off.

[thumb]http://ij.supramania.com/hcore04.jpg[/thumb]

 

[Kai]

I bought a Rolson one for about £26, pretty good but like IJ said - you have to measure it right.

 

[Supracentral]

I've got a Fluke 62. Most of my metering tools are Fluke. It's not the cheapest stuff out there, but it's damned good stuf.

 

[CyFi6]

About measuring at the right angles and such, are you saying that is specific to the gun or for temp guns in general. I know the one i have used you need to point it right but it wasnt a big deal, just wondering if you are saying the cheaper ones are worse or what.

This is a useful tool that will likely be in my box for many years to come, so i dont mind spending a litle bit more to get something that will last me. I will look into the fluke, ive used their dmm's and such and they seemed quality.


Hmm upon inspection, it looks like this gun is the same exact one between raytek and fluke.

http://www.amazon.com/Fluke-62-Mini-Infrared-Thermometer/dp/B000MX5Y9C
http://www.amazon.com/Raytek-MT6-MiniTemp-Infrared-Thermometer/dp/B000O80B5M

 

[Supracentral]

Wow, I never noticed that. Looks like the same unit.

 

[IJ.]

Ran into this with Heat Guns they all seemed to come out of one factory just with different stickers

 

[MK3Brent]

I'll check what brand we have at work... but it's TERRIBLE... Off by 20-30c.
So don't get it.

 

[jetjock]

Mine is the Raytek ST25 AutoPro. Dual laser focusing, lighted head, ºC or ºF selectable with peak hold, magnetic base, 16:1 spot size. Accuracy ±1%. Does a nice job. Like Mike most of my other test and measurement gear is Fluke but I'm slowly switching over to Agilent.

Btw no surprise on the similarity between those guns. Fluke owns Raytek.

 

[3p141592654]

Unless you know the IR emissivity of the object being measured, its really just a guess.

Off angle measurements are even more unpredictable. For a reflective surface, the measurement is of whatever object is imaged by the reflection off the surface, and for an absorptive surface (true blackbody) you should get an accurate reading assuming the gun is set for an emissivity =1.

highly polished metal e~0.02
black body e~1

so uncertainty is ~17dB on a gun with no emissivity cal.

 

[CyFi6]

so what is the best alternative?

 

[gaboonviper85]

so what is the best alternative?

if it burns you it's hot....if it doesn't than it's not hot...works good!

 

[3p141592654]

If you want accuracy, nothing beats a thermocouple. IR guns are convenient, but they need to be calibrated to the surface you are measuring, if you want accuracy. If, for example, you mostly use it to measure exhaust systems, then an hour spent calibrating the IR gun to a thermocouple reading from exhaust components will allow you to learn the correct emissivity to use for that application. If your gun doesn't have a cal option, then you will just have to accept that the accuracy will vary.

 

[CyFi6]

ah, i see. I have a "thermocouple" (didnt know that word before, thanks for teaching me!) built into my DMM, but its so hard to use as i have to hold it against the part im measuring, and in most cases the part i want to measure is way too hot to touch, so its very hard to use.

 

[Supracentral]

ah, i see. I have a "thermocouple" (didnt know that word before, thanks for teaching me!) built into my DMM, but its so hard to use as i have to hold it against the part im measuring, and in most cases the part i want to measure is way too hot to touch, so its very hard to use.

Welding gloves help for that.

 

[CyFi6]

Ive gone ahead and purchased an infrared temperature gun, but now i will know for the best accuracy i can use my little thermocouple. Good stuff to know thanks again.

 

[jetjock]

All of what 3p says is true but adjustable emissivity doesn't come cheap. A way to get good results is to use a strip of black tape on reflective surfaces. That's what I do for things like the T stat housing and accuracy is then very good when compared to my Type K surface TC. Also accuracy isn't an issue many cases because it's the relative change you're looking for. Catalyst, radiator, and cylinder misfire work are examples. The point is if you understand the limitations of IR it remains a handy tool and in most cases I'll reach for the gun before I'll reach for the Omega kit.

 

[3p141592654]

JJ's black tape trick is well thought out. If you can force the surface to be approximately a black body then you will get better results.

The hardest surfaces to measure are highly reflective ones, as they behave like a mirror, and you end up measuring whatever is being reflected, which might even be yourself if you are pointing the gun normal (90degrees) to a flat surface! This is usually obvious though, as the laser spot will be brightly shining on wherever the reflection originates.