Quick heads up, Maplin have an infrared non contact thermometer on sale
for 19.99, reduced from 35. ISTR some people were wanting them for
balancing CH systems and other DIY stuff?
--
Clint Sharp

Clint Sharp laid this down on his screen :
Quick heads up, Maplin have an infrared non contact thermometer on sale for
19.99, reduced from 35. ISTR some people were wanting them for balancing CH
systems and other DIY stuff?

If it is the orange and grey plastic cased unit, they have been that
price for a good six months. I bought one to replace a more substantial
(and expensive) one after I dropped it and the display shattered. The
new one is good and accurate, but the display is not so large. It
compared well against a £100 Fluke unit, as in correct to the last
digit.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:

Clint Sharp laid this down on his screen :
Quick heads up, Maplin have an infrared non contact thermometer on sale for
19.99, reduced from 35. ISTR some people were wanting them for balancing CH
systems and other DIY stuff?

If it is the orange and grey plastic cased unit, they have been that
price for a good six months. I bought one to replace a more substantial
(and expensive) one after I dropped it and the display shattered. The
new one is good and accurate, but the display is not so large. It
compared well against a £100 Fluke unit, as in correct to the last
digit.

SNAP. I droped mine as well and it just would not work afterward.
Now while it was a great toy and I guess I will pick up another one
I was always confused by the way it utterly failed to properly report
the temperature when upto bare copper pipe.

It seemed good when pointed at most other things, it was just copper
it failed on!!

Any ideas?

Fergus McMenemie submitted this idea :
Harry Bloomfield wrote:

Clint Sharp laid this down on his screen :
Quick heads up, Maplin have an infrared non contact thermometer on sale for
19.99, reduced from 35. ISTR some people were wanting them for balancing CH
systems and other DIY stuff?

If it is the orange and grey plastic cased unit, they have been that
price for a good six months. I bought one to replace a more substantial
(and expensive) one after I dropped it and the display shattered. The
new one is good and accurate, but the display is not so large. It
compared well against a £100 Fluke unit, as in correct to the last
digit.

SNAP. I droped mine as well and it just would not work afterward.
Now while it was a great toy and I guess I will pick up another one
I was always confused by the way it utterly failed to properly report
the temperature when upto bare copper pipe.

It seemed good when pointed at most other things, it was just copper
it failed on!!

Any ideas?

I have the same problem. I have not tried it, but what about wrapping
some black tape around the pipe?

Odd how they work on some surfaces, but not others. They seem to half
work on a stream of water, or even better water run over a stainless
surface. I would not be without mine, certainly beats climbing to check
a/c output and pipe temperatures.


It wasn't the orange one I broke BTW, but it more expensive
predecessor.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

In an earlier contribution to this discussion,
Fergus McMenemie wrote:

Now while it was a great toy and I guess I will pick up another one
I was always confused by the way it utterly failed to properly report
the temperature when upto bare copper pipe.

The reading you get does depend on the reflectivity of the surface.

For consistency, I've fixed little squares of black tape near the inlet and
outlet of each radiator, and on every pipe whose temperature I want to
measure.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

In article ,
(Fergus McMenemie) writes:
SNAP. I droped mine as well and it just would not work afterward.
Now while it was a great toy and I guess I will pick up another one
I was always confused by the way it utterly failed to properly report
the temperature when upto bare copper pipe.

It seemed good when pointed at most other things, it was just copper
it failed on!!

They are normally calibrated for surfaces with an emissivity of
about 0.95 and that's not far off what most surfaces are.
Polished copper (as in a piece of new pipe) has an emissivity of
about 0.04 -- that means that the infrared emitted by it is
simply far too dim for the thermometer to be able to see anything.

Copper sheet is used as thermal wrap for telecommunications and
other space satelites because it's so good at shielding against
both absorbing and emitting infrared. Most polished bare metals
will behave similarly, but most of them don't last more than
that a few hours before they've tarnished enough not to be bare
metal anymore (even if the tarnished coating may not be obvious
to you). Copper takes much longer.

As others have said, a bit of sticky tape or dab of paint will
do. I sometimes point the thermometer at the radiator boss where
the inlet/outlet pipes connect - the enamel coating works fine.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Clint Sharp wrote:
Quick heads up, Maplin have an infrared non contact thermometer on sale
for 19.99, reduced from 35. ISTR some people were wanting them for
balancing CH systems and other DIY stuff?

Anyway of modding this as a poor man's thermal imager? Say, some control
mechanism to make the unit step over specified small incremental
distances, and then do a lovely false colour plot from data read?

(Nope, not the radio controlled helicopter again...)

--
Adrian C

In article ,
Adrian C writes:
Clint Sharp wrote:
Quick heads up, Maplin have an infrared non contact thermometer on sale
for 19.99, reduced from 35. ISTR some people were wanting them for
balancing CH systems and other DIY stuff?

Anyway of modding this as a poor man's thermal imager? Say, some control
mechanism to make the unit step over specified small incremental
distances, and then do a lovely false colour plot from data read?

(Nope, not the radio controlled helicopter again...)

Probably much easier to take a cheap B/W security camera, most of which
operate down into the infrared anyway and often even have a filter to
prevent them seeing in the infrared. Take out any such filter, and
replace it with a filter to block the visible light.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Fergus McMenemie" wrote in message
...
Harry Bloomfield wrote:

Clint Sharp laid this down on his screen :
Quick heads up, Maplin have an infrared non contact thermometer on sale
for
19.99, reduced from 35. ISTR some people were wanting them for
balancing CH
systems and other DIY stuff?

If it is the orange and grey plastic cased unit, they have been that
price for a good six months. I bought one to replace a more substantial
(and expensive) one after I dropped it and the display shattered. The
new one is good and accurate, but the display is not so large. It
compared well against a £100 Fluke unit, as in correct to the last
digit.

SNAP. I droped mine as well and it just would not work afterward.
Now while it was a great toy and I guess I will pick up another one
I was always confused by the way it utterly failed to properly report
the temperature when upto bare copper pipe.

It seemed good when pointed at most other things, it was just copper
it failed on!!

It needs a surface with a high emissivity apparently after speaking to
someone from Fluke. The surface doesn't have to be black, but needs to have
a matt or slightly rough finish. These thermometers give false readings on
other surfaces. It was suggested to me that painting a surface with tippex
would be good enough to get an accurate reading.

"Mr Benn" %%%@%.%% wrote:

It needs a surface with a high emissivity apparently after speaking to
someone from Fluke. The surface doesn't have to be black, but needs to have
a matt or slightly rough finish.


Will human skin do?

In article ,
Bruce writes:
"Mr Benn" %%%@%.%% wrote:

It needs a surface with a high emissivity apparently after speaking to
someone from Fluke. The surface doesn't have to be black, but needs to have
a matt or slightly rough finish.


Will human skin do?

Yes. Almost anything except polished metal surfaces will do.
Avoid pointing the laser in someone's eye though!
(Suggest turning the laser off if you can - it's not very useful.)

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 5 Mar, 23:25, Adrian C wrote:

Anyway of modding this as a poor man's thermal imager?

Why not just buy one?

http://www.abex.co.uk

Andrew Gabriel submitted this idea :
Yes. Almost anything except polished metal surfaces will do.
Avoid pointing the laser in someone's eye though!
(Suggest turning the laser off if you can - it's not very useful.)

I find the laser spot very useful - with it you can 'hit' a spot from
way across a room or an high ceiling to get the temperature of a
distant object. They make them very much easier to aim.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

In article ,
Harry Bloomfield writes:
Andrew Gabriel submitted this idea :
Yes. Almost anything except polished metal surfaces will do.
Avoid pointing the laser in someone's eye though!
(Suggest turning the laser off if you can - it's not very useful.)

I find the laser spot very useful - with it you can 'hit' a spot from
way across a room or an high ceiling to get the temperature of a
distant object. They make them very much easier to aim.

It's misleading - it doesn't measure the temperature of the spot.
It sees a cone, most of them with a 1:8 ratio, so it measures a
circle of diameter about 1/8th of the distance between the gun
and the target. I don't know what their behaviour is when there
are many different temperatures visible withing the viewing cone.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 6 Mar, 18:07, (Andrew Gabriel) wrote:

I don't know what their behaviour is when there
are many different temperatures visible withing the viewing cone.

Generally they over-read the mean temperature, owing to the Stefan-
Boltzmann law. Especially so when there's a small hotspot in a largely
cooler field, it gets a disproportionate weighting.

Andrew Gabriel submitted this idea :
It's misleading - it doesn't measure the temperature of the spot.
It sees a cone, most of them with a 1:8 ratio, so it measures a
circle of diameter about 1/8th of the distance between the gun
and the target. I don't know what their behaviour is when there
are many different temperatures visible withing the viewing cone.

My own use of one leads me to a conclusion that they indicate a biased
average, of the temperature of the cone. Biased some way towards the
temperature of the hotter object they see.

It is fairly easy to check the accuracy of the spot, by pointing the
unit at a warm radiator and seeing how far off the radiator you have to
aim to get a background temperature.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Andrew Gabriel wrote:

Copper sheet is used as thermal wrap for telecommunications and
other space satelites because it's so good at shielding against
both absorbing and emitting infrared.

I thought they used gold! Beats out thinner (= lighter) and the cost of
the material is nothing to the cost of getting it up there...

Andy

On Fri, 06 Mar 2009 21:00:19 +0000, Andy Champ
wrote:

Andrew Gabriel wrote:

Copper sheet is used as thermal wrap for telecommunications and
other space satelites because it's so good at shielding against
both absorbing and emitting infrared.

I thought they used gold! Beats out thinner (= lighter) and the cost of
the material is nothing to the cost of getting it up there...

They do.

--

On 06 Mar 2009 08:29:01 GMT, Andrew Gabriel wrote:

Probably much easier to take a cheap B/W security camera, most of which
operate down into the infrared anyway and often even have a filter to
prevent them seeing in the infrared. Take out any such filter, and
replace it with a filter to block the visible light.

That'll be near infrared though won't it? The thermal image cameras the
the fire service use to locate hot spots or people in smoke filled
buildings or the police use for spotting hot tyres/engines or hiding
people at night use far infrared.

I have a cheap B&W camera that suffers CCD overload if you point a IR
remote at it and can almost see by the light from a few IR LEDs. It shows
the glowing embers of a fire quite well that my eyes can't see. But these
are all quite bright sources it's no good for pointing out the window at
night to spot prowlers. Or pointing at the house to see where the heat is
being lost.

--
Cheers
Dave.

On 6 Mar, 21:00, Andy Champ wrote:
Andrew Gabriel wrote:

Copper sheet is used as thermal wrap for telecommunications and
other space satelites because it's so good at shielding against
both absorbing and emitting infrared.

I thought they used gold!

Metal foil wraps are used to _heat_ equipment, as it has a high
absorptance / emittance ratio where it absorbs solar radiation in the
visible but has low emittance in the infra red (spacecraft are colder
than the Sun, thus emit at longer wavelengths). Titanium is used, as
it makes a useful foil material, but both gold and copper are used too
as outer foils. White paint is used in the opposite sense, for
cooling, as it has a low absorptance / emittance ratio (emits more IR
than solar gain). This is the coating that has the most trouble with
aging under the harsh UV and vacuum environment.

Plastic (Kapton, Mylar, Teflon) multi-layer foils with a vacuum-
sputtered metal (gold, aluminium, silver) coating on them are for
insulation and thermal stability, not for passive thermal control
through solar radiation.

On 06 Mar 2009 17:26:34 GMT, a certain chimpanzee,
(Andrew Gabriel) randomly hit a keyboard
and produced:

(Suggest turning the laser off if you can - it's not very useful.)

My cat would disagree.
--
Hugo Nebula
"If no one on the Internet wants a piece of this,
just how far from the pack have you strayed?"