Thought a brake was hanging up. Got out, and dig the laser aimed
IR thermometer out of my tool box. Go around and check the temps
of the brakes, to find the one running hot.

Other use -- read a thermostat on top of the motor. Find what
temp the thermostat maintains.

--

Christopher A. Young
You can't shout down a troll.
You have to starve them.
..

Stormin Mormon wrote:
Thought a brake was hanging up. Got out, and dig the laser aimed
IR thermometer out of my tool box. Go around and check the temps
of the brakes, to find the one running hot.

Other use -- read a thermostat on top of the motor. Find what
temp the thermostat maintains.


ayup, they are very nice when you have a car with an uncalibrated
temperature gauge. Turns out 3/4 scale on a '55 Studebaker converted to
12V with the gauges running off a 6V "Runtz" voltage dropper (probably
not a configuration the factory anticipated G) is about 180 degrees -
a little warm for the stock 160 degree thermostat, but not so bad for a
'63 Avanti engine with a factory 170 degree 'stat, actually running a
180 stat because you can't get a 170 anymore.

Had I not had the IR thermometer, I might have ASSumed that I had an
overheating problem when in fact it was a gauge calibration issue.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

On Thu, 18 Jan 2007 17:46:27 -0500, "Stormin Mormon"
wrote:

Thought a brake was hanging up. Got out, and dig the laser aimed
IR thermometer out of my tool box. Go around and check the temps
of the brakes, to find the one running hot.

Other use -- read a thermostat on top of the motor. Find what
temp the thermostat maintains.

I don't have a thermal camera, but I did a 'scan' of some walls and
ceilings, and found I had cold spots. I found my IR thermometer very
useful.

tom @ www.MedJobSite.com

Stormin Mormon wrote:

Thought a brake was hanging up. Got out, and dig the laser aimed
IR thermometer out of my tool box. Go around and check the temps
of the brakes, to find the one running hot.

Other use -- read a thermostat on top of the motor. Find what
temp the thermostat maintains.

--

Christopher A. Young
You can't shout down a troll.
You have to starve them.
.

Yep, they're so useful I keep one in the shop and one in the kitchen.

Pete C.

On Thu, 18 Jan 2007 17:46:27 -0500, "Stormin Mormon"
wrote:

Thought a brake was hanging up. Got out, and dig the laser aimed
IR thermometer out of my tool box. Go around and check the temps
of the brakes, to find the one running hot.

Other use -- read a thermostat on top of the motor. Find what
temp the thermostat maintains.

Does it work for finding cold leaks into the house, or heat leaks out
of the house? I mean, can you point it at the edges of the door or
window or pipe and get a temp reading off of air that is blowing in or
out, or do only solid things radiate IR?

Point it up at the zenith of a clear, dark sky on a warm night. Brrr!

"Stormin Mormon" wrote:

Does it work for finding cold leaks into the house, or heat leaks out
of the house? I mean, can you point it at the edges of the door or
window or pipe and get a temp reading off of air that is blowing in or
out, or do only solid things radiate IR?

Gases don't radiate, generally, but you might sense lower-temp wood trim.
Or feel around the door with your hands on a cold day, with a large window
exhaust fan running. You can find which rooms have the largest air leaks
and measure airsealing progress with a $70 Kestrel 1000 wind velocity meter
in another partially open window. When you open a door to a leaky room,
the air velocity will decrease. As you airseal, it will increase.

Richard J Kinch wrote:

Point it up at the zenith of a clear, dark sky on a warm night. Brrr!

Inexpensive IR thermometers ignore water vapor (so people can use them in
boiler rooms full of steam), so this might also work on a warm summer day.

Nick

Stormin Mormon wrote:
Thought a brake was hanging up. Got out, and dig the laser aimed
IR thermometer out of my tool box. Go around and check the temps
of the brakes, to find the one running hot.

Other use -- read a thermostat on top of the motor. Find what
temp the thermostat maintains.

--

Christopher A. Young
You can't shout down a troll.
You have to starve them.
.

Check breakers and wiring.

Dave

wrote:
"Stormin Mormon" wrote:

Does it work for finding cold leaks into the house, or heat leaks out
of the house? I mean, can you point it at the edges of the door or
window or pipe and get a temp reading off of air that is blowing in or
out, or do only solid things radiate IR?

Gases don't radiate, generally, but you might sense lower-temp wood trim.

My house inspector just pointed his at the registers of the furnace/AC
to see how well the air was distributing. I assume after a short time
the solid material equilibrates to the temp of the air going through.

z wrote:

wrote:

Gases don't radiate, generally, but you might sense lower-temp wood trim.

My house inspector just pointed his at the registers of the furnace/AC
to see how well the air was distributing. I assume after a short time
the solid material equilibrates to the temp of the air going through.

Sure. If you want the room air temp, wave a piece of paper in the air
for a few seconds, then aim at that.

Nick

Point it up at the zenith of a clear, dark sky on a warm night. Brrr!

Inexpensive IR thermometers ignore water vapor (so people can use them
in boiler rooms full of steam), so this might also work on a warm
summer day.

Don't misunderstand. You're reading the near-absolute-zero temperature of
outer space, through a thin veil of warmer air. The integrated temperature
is still below zero even on a warm night. The clear night sky is a cold
window.

"Ignore water vapor" is fantasy. Blackbody radiation is the same whether
it's a gas, liquid, or solid radiator.

Richard J Kinch wrote:

Point it up at the zenith of a clear, dark sky on a warm night. Brrr!

Inexpensive IR thermometers ignore water vapor (so people can use them
in boiler rooms full of steam), so this might also work on a warm
summer day.

Try it.

Don't misunderstand. You're reading the near-absolute-zero temperature of
outer space, through a thin veil of warmer air.

I understand that.

The integrated temperature is still below zero even on a warm night.

What's an "integrated temperature"? :-)

The clear night sky is a cold window.

Clear skies are, but water vapor and clouds absorb IR. So do windows...

"Ignore water vapor" is fantasy. Blackbody radiation is the same whether
it's a gas, liquid, or solid radiator.

Very wrong :-)

Nick

The integrated temperature is still below zero even on a warm night.

What's an "integrated temperature"? :-)

What the radiation thermometer reads, looking at the background of outer
space, overlaid with a transparent but blackbody-radiating layer of
atmosphere. This type of thermometer is performing a digital numerical
integration as part of its analysis of the blackbody spectrum of the
target.

The clear night sky is a cold window.

Clear skies are, but water vapor and clouds absorb IR. So do windows...

No, your understanding is naive. Ceramics emit radiation like anything
else. Nothing absorbs IR from the darkness of outer space, because there's
no IR to absorb. A room temperature skylight window is emitting IR, not
absorbing it, on a clear night.

In article , Richard J Kinch wrote:

No, your understanding is naive. Ceramics emit radiation like anything
else. Nothing absorbs IR from the darkness of outer space, because there's
no IR to absorb. A room temperature skylight window is emitting IR, not
absorbing it, on a clear night.

Actually, it's doing *both*, isn't it? I think Nick's point was that window
glass isn't nearly as transparent to IR as it is to visible light. Emissions
from an IR source inside the building will be mostly absorbed by the skylight,
instead of passing through, no? Meanwhile, the skylight will radiate IR as
well.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Richard J Kinch wrote:

The integrated temperature is still below zero even on a warm night.

What's an "integrated temperature"? :-)

What the radiation thermometer reads, looking at the background of outer
space, overlaid with a transparent but blackbody-radiating layer of
atmosphere...

Which absorbs IR...

The clear night sky is a cold window.

Clear skies are, but water vapor and clouds absorb IR. So do windows...

No, your understanding is naive.

Incorrect.

Nick

Doug Miller wrote:

... Emissions from an IR source inside the building will be mostly absorbed
by the skylight, instead of passing through, no?

I think so, for wavelengths longer than 3 microns.

Meanwhile, the skylight will radiate IR as well.

Sure, but we were talking about sky vs skylights, no? A cheap IR thermometer,
eg Raytek's $99 version, will ignore water vapor absorption and read a lower
sky temp than an expensive one, eg a $1000 Exeltech, which will read a lower
sky temp on a cloudy or humid day.

Nick

Doug Miller writes:

Actually, it's doing *both*, isn't it? I think Nick's point was that
window glass isn't nearly as transparent to IR as it is to visible
light. Emissions from an IR source inside the building will be mostly
absorbed by the skylight, instead of passing through, no?

Yes and no. Yes, it absorbs some incident radiation instead of directly
transmitting it (depending on wavelength). But it re-radiates much of what
it absorbs, which is an indirect transmission.

There is a mythical version of "glass blocks IR" that some people think
makes cars hot on a sunny day. In fact it is the *transmission* of shorter
IR sunlight (many 1000s deg K blackbody) via the glass into the car
interior, where it is absorbed on the interior surfaces, and re-radiated at
longer IR spectra (several 100s deg K blackbody) that is blocked by the
glass.

What the radiation thermometer reads, looking at the background of outer
space, overlaid with a transparent but blackbody-radiating layer of
atmosphere...

Which absorbs IR...

No, like all matter, the atmosphere both emits and absorbs radiation. At
night it emits more than it absorbs (thus cooling itself while keeping us
warm down here, happily), so it is a net emitter, not an absorber. When
you point your Raytek at the clear night sky, you are measuring that
emission. If the atmosphere (net) absorbed IR, the sky would feel
cryogenic like outer space, instead of just somewhat cooler than the
surface, on a warm, clear night.

There is this mythology of the atmosphere (glass, etc.) being nothing but a
sink for radiation. Just enough physics to get it wrong. Typical of
global warming advocates.

Richard J Kinch wrote:
What the radiation thermometer reads, looking at the background of outer
space, overlaid with a transparent but blackbody-radiating layer of
atmosphere...

Which absorbs IR...

No, like all matter, the atmosphere both emits and absorbs radiation. At
night it emits more than it absorbs (thus cooling itself while keeping us
warm down here, happily), so it is a net emitter, not an absorber. When
you point your Raytek at the clear night sky, you are measuring that
emission. If the atmosphere (net) absorbed IR, the sky would feel
cryogenic like outer space, instead of just somewhat cooler than the
surface, on a warm, clear night.

There is this mythology of the atmosphere (glass, etc.) being nothing but a
sink for radiation. Just enough physics to get it wrong. Typical of
global warming advocates.


Now that everyone has said how cool IR thermometers are (& they're one
of the few tools I don't have)


any suggestions on mfr / models?

cheers
Bob

Richard J Kinch writes:

There is this mythology of the atmosphere (glass, etc.) being nothing
but a sink for radiation. Just enough physics to get it wrong.
Typical of global warming advocates.

I should specify the "greenhouse effect" in this regard, not global warming
in general.

BobK207 writes:

any suggestions on mfr / models?

My Raytek MiniTemp is dead on:

http://www.grainger.com/Grainger/wwg...mId=1611697546

I haven't tried the Chinese clones that are 1/4 the price:

http://search.harborfreight.com/cpis...rd=thermometer

Richard J Kinch wrote:

What the radiation thermometer reads, looking at the background of outer
space, overlaid with a transparent but blackbody-radiating layer of
atmosphere...

Which absorbs IR...

No, like all matter, the atmosphere both emits and absorbs radiation...

No? This is unusual logic. It both emits and absorbs radiation,
but it doesn't absorb IR? :-)

When you point your Raytek at the clear night sky, you are measuring that
emission...

I don't think so. Try it. I've pointed my Raytek at night skies and daytime
skies, with clouds, and read similar very cold temperatures. When I point
a $1K Exeltech at the same cloudy sky, I read a much higher temp. I think
the Raytek measures emissive power in a narrow wavelength band that excludes
the strong water vapor absorption bands around 1, 1.4, and 1.8 microns, but
the Exeltech looks at more of the spectrum.

Nick

Richard J Kinch wrote:

Doug Miller writes:

Actually, it's doing *both*, isn't it? I think Nick's point was that
window glass isn't nearly as transparent to IR as it is to visible
light. Emissions from an IR source inside the building will be mostly
absorbed by the skylight, instead of passing through, no?

A pane of glass transmits about 90% of the terrestrial solar spectrum
(which has very little power at wavelengths longer than 2.5 microns)
and blocks almost all of the IR spectrum longer than 3 microns. Wien's
displacement law says an 80 F (282K) black body has a spectral peak
at 2897.8/282 = 10 microns... 966K (1279 F) has a 3 micron peak.

Yes and no. Yes, it absorbs some incident radiation instead of directly
transmitting it (depending on wavelength). But it re-radiates much of what
it absorbs, which is an indirect transmission.

Windows transmit a lot more beam sun power than the IR they reradiate,
since houses scatter and absorb incoming sun over a large interior
surface and do not contain IR beam suns of their own.

There is a mythical version of "glass blocks IR" that some people think
makes cars hot on a sunny day. In fact it is the *transmission* of shorter
IR sunlight (many 1000s deg K blackbody) via the glass into the car
interior, where it is absorbed on the interior surfaces, and re-radiated at
longer IR spectra (several 100s deg K blackbody) that is blocked by the
glass.

Glass blocking IR makes cars hot in the sense that without glass, they
would be cooler. Polycarbonate also blocks IR. Polyethylene doesn't.
My sunspace with 256 ft^2 of poly film glazing seldom reaches 100 F
on sunny winter days.

Nick

It both emits and absorbs radiation, but it doesn't absorb IR?

Right, it both emits and absorbs (and transmits as well), but is a net
emitter at certain times.

Richard J Kinch wrote:

It both emits and absorbs radiation, but it doesn't absorb IR?

Right, it both emits and absorbs (and transmits as well), but is a net
emitter at certain times.

When it's also absorbing IR.

Nick

Right, it both emits and absorbs (and transmits as well), but is a net
emitter at certain times.

When it's also absorbing IR.

Right, it both emits and absorbs.