Infrared Thermometer Test

[dragon813gt]

deleted

[Artful]

Thanks for testing and posting the results.

[Walter Laich]

dog must be healthy--has a cold nose

[Catshooter]

Good test run. I agree with you, IRs don't work on molten lead nor any other reflective object.


Cat

[454PB]

Did you use a copper penny?

Did you wait until the penny turned black?

[EDG]

Your UEI measured measured 675 lead at 355 and with a penny at about 400?

Are you sure you did not have C and F crossed up?
I have no idea what you were demonstrating with the FLIR.

In any even a thermometer will not measure the temperature of a mold.

[theperfessor]

I measure the temperature of my molds with a thermocouple hooked to a PID controller that controls my hot plate. Been using one that screws into a 1/4-20 threaded hole but just got a few probe types from Auber to try. One of our better mold makers I believe offers the option to have the mold drilled for a TC probe.

I've tried the IR thermometer from HF and got the same general results as the OP. And I came to the same conclusion, for about the same price you can get a good analog thermometer that's accurate enough, and for a few dollars more you can go digital.

IR thermometers are useful in some circumstances, but checking alloy temp isn't one of them, at least in my book. But to each their own, if anyone gets good results and they're happy with it then go right ahead and use it.

[Kull]

I've found the same thing as the op with my Raytek branded IR thermometer. Shiny surfaces just don't work.

[John Boy]

dragon813gt, I sure hope that a Moderator is reading this thread. It is deserving of a Sticky! Don't know the number of times a caster sees a deal on these IR's and here we go again dispelling that they don't work for casting instead of just buy a Tel-Tru bimetal thermometer

Thanks Kindly for Your Tests!

[psychicrhino]

The pup shot was my favorite.

[tom357mag]

I am just getting into casting and was hoping to use my IR but i guess Im beat! Bummer

[Errokk]

It plainly says in the instructions of most IR thermometers that sharply curved and reflective surfaces will NOT read correctly.

I have 3 IR thermometers for different uses being as my job also requires them for quick temp readings. Don't get me wrong, I'd love to get away with using an IR thermometer for molten lead and casting, just not gonna be accurate until they find a way to make them read shiny surfaces.

[FLINTNFIRE]

Thank you for the post , as I was thinking of getting a IR , already have the thermometer from NOE , was just thinking of the IR for hitting the mold temperature , now I see that is a waste , so once more thanks for the information.

[Frozone]

I measure the temperature of my molds with a thermocouple hooked to a PID controller that controls my hot plate. Been using one that screws into a 1/4-20 threaded hole but just got a few probe types from Auber to try. One of our better mold makers I believe offers the option to have the mold drilled for a TC probe.

I've tried the IR thermometer from HF and got the same general results as the OP. And I came to the same conclusion, for about the same price you can get a good analog thermometer that's accurate enough, and for a few dollars more you can go digital.

IR thermometers are useful in some circumstances, but checking alloy temp isn't one of them, at least in my book. But to each their own, if anyone gets good results and they're happy with it then go right ahead and use it.


I have a bunch of custom probes coming in a week or 2.
They are stainless steel, 3mm diameter and 20mm long with a flange and spring strain relief like my thermocouples. It also has a 3 foot long Teflon coated braided SS cable .
The 3mm tip is smaller (by 1mm) than the one from NOE and the whole thing fits nicely under the handles.
I have successfully used one to instrument a MP mold as well.

They are class A RTD pt100 devices good to 400ºC.
Any one interested PM me, Bad news is I didn't buy a lot so I paid a lot. $20 each.

I'm working hard to find a supplier of pyrometers similar to the Auber 1813x - for less than the $50 that Auber wants. Also trying to find one the takes 110 ac not the 12V dc of the Auber unit.

FWIW The NOE unit has a Great probe, But is not compatible with anything except the device it comes with. It's a 100K ohm RTD, a rather rare critter.


Oh yeah, And Dragon where did you get that beautiful PID Unit???

[oldscool]

that dog should have shown cool ears

try a Fluke 66 or 68 or variants, and learn how to set the emissivity and they will surprise you with the results

Is boiling water hotter on the bottom, middle, or top of the pot, and how did you measure the difference???

[Larry D.]

Great post.
I can say without hesitation that I wish I'd seen it before I wasted the money on my IR.

[williamwaco]

Thanks.

Actual test data is always appreciated.


.

[BubbaJon]

I gotta say those FLIR pics were cool as heck!
Outstanding and I think we can definitively put this one to rest.
Thumbs up!

[blikseme300]

Great post.
I can say without hesitation that I wish I'd seen it before I wasted the money on my IR.

I write off such purchases as school fees as learning is seldom free.

[mold maker]

Hmmmmmm. I never thought of it that way. Wonder if my tax advisor will agree.

[Dale in Louisiana]

One word: Emissivity!

It is, roughly speaking, the characteristic that allows a body (or a puddle of lead) to transmit heat energy. The best emissivity is 1.0, a theoretical number. You can come close in the real world with a flat black surface. The shinier the surface, the worse the emissivity.

It works like heat absorption in reverse. You all know how a flat black surface will get much hotter in sunlight than a reflective silver one, right? That's the difference between an emissivity of 0.98 and 0.05.

More expensive thermal imaging equipment has means to change the emissivity numbers it uses to calculate actual temperatures from the infrared energy that the sensor head (or camera) receives.

That said, a decent IR thermometer will give you the same (wrong) number for an observed temperature of that puddle of lead. You can use that information to compare this week's melt versus last week's. If you did a good job of casting last week when your thirty-dollar IR thermometer said 350 degrees, then you'll get the same result this week, even though in both cases the temperature was actually 725 degrees.

That's why one of the common rules in the business of infrared thermography interpretation is to compare like objects. If one reads significantly higher than the one identical to it on the other side of the cabinet chances are really good that it is indeed hotter even though you might not know the absolute temperature.

How do you get around this problem with a cheapo thermometer? Find something dark that's at the same temperature. Float bit of steel that's dark. Or shoot the wall of the crucible.

dale in Louisiana
(who's made quiet a few bucks with IR thermography over the years)