Ir temp gun question

[Dreadfrog]

Do infa red temp guns only read temp of hard surfaces ?
Can you read air temp with them
Can they be used to check enclosure temps or just temp of glass , substrate , plants ,



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[Louis Charles Bruckner]

It can only read non reflective surface temps, not air temps
Edit: Think about it you are reading infra red light being emitted by objects.

I use thermal imagers and IR guns for work.
and if I want to get a ambient room temp I just read the temps of the walls and ceiling and do a average.
But that doesn't work well for small enclosures.

you also have to take in to consideration the target area size vrs the distance from the gun to the target.
it averages the target area.

i.E if you are 15 inches from the target the read area is 1 foot in diameter. (this is just a example) you will need to read the
directions of the IR gun.

[maxQ]

Ill let ya know, I just bought one on Amazon today

[poison]

Yes "Temp guns" only measure surface/basking temps. Its said that you can read the ambient temp of a spot by measuring the water temperature in that area. Not sure if that is true or not. I would try it out but I need a new temp gun.

[Louis Charles Bruckner]

Sorry Daniel but water surface is reflective even muddy water is reflective and you will only read the temp of what eve is around it.
Even a semigloss paint job is reflective enough to fool IR guns.

just a few months back I noticed a grocery store worker using a IR gun to read the temp of food warmer that was lined with aluminum foil.
And she was on the radio calling the store manager that the warmer was broken that it was reading just 68F and it should be reading 120F

I waited for the manager to arrive before offering help.
I explained that she was actually measuring the temp of the ceiling in the store.
Both her and the manager didn't understand.
So I asked her to point it at the celling and see what was the temp was. 68F she said.

I explained what was going on and asked if the manger could get a price sticker from the delli counter.
that was blank. I knew that these stickers were a matt finish and not glossy.
and as soon as I stuck it to the pan of the food warmer the sticker went completely black.
I said ok now from that reaction I know that that surface is over 120F since the thermal paper turned black.
now lets look at that IR gun. it had a diagram on the top of it showing the sensing area size per distance from the gun.
so I showed them that reading a surface from a foot away the seining area is about the same size as the sticker and to aim the laser
at the sticker and you will get a accurate reading.

Then she said I also have to read the containers of food. I said simply just read the price sticker. as long as it is not a sticker that is glossy.
or silver.

So reading the glass of a enclosure is not a good place to get a reading. unless you put a small strip of scotch tape on the glass.
Here is a little demo I did for my technical director that didn't understand that the new parts we got to replace the old could not be thermal
imaged.
The first image of the parts lined up in glasses.
one part was put in the freezer another was put in hot water for a while and one was left in room temp for a few hours.
They all have a pice of scotch tape on them.


This image shows how the areas that don't have scotch tape are the same color or shooing the same temp.
but the areas where the tape is vastly different color shooing the actual temp of each part.


the one to the far left is the warmest of the three and the one in the middle is closer to room temp and the one on the end is the coolest.
you have to read the directions carefully of the IR gun.