Cheap thermometer calibration technique?

Ok, he is AlwaysWrong. But when a sensible person asks a sensible question, and the GreatBlunderer gives him advice that is flat preposterous, he ought to be corrected.
John
Reply to
John Larkin
Loading thread data ...
Both are about 2:1 better than aluminum. The factor is even higher compared to common aluminum alloys; hardly anybody wants to machine pure aluminum, and the alloying wrecks both the electrical and thermal conductivity.
You fuck with yourself. Or job is to laugh.
John
Reply to
John Larkin
Yes, I can see your point.
Perhaps someone as a service to the public could write a little bot that puts a follow up on his posts pointing his out.
Reply to
MooseFET
On May 9, 7:56 am, John Larkin [......]
In all metals, the thermal and electrical conductivity track each other quite nicely. Copper alloys such as brass are way less conductive. The atomic clock folks use a copper alloy that is very resistive to make heaters.
Reply to
MooseFET
The "expert source" I'm referring to is the document you pointed to several times.
Reply to
DaveC
True. But this may not be the last temperature measurement he'll ever make. -- John
Reply to
John O'Flaherty
So, you need a "Garbage bot"? ;-)
Reply to
Michael A. Terrell
Hhat can I say but WrongAgain?
Look into a mirror that's reflecting the sky into your eyes. You see the color of the sky. Now take off your glasses or equivalent to defocus the scene. You still see the color of the sky.
If defocussing means you are averaging unwanted objects into the image with the desired target, sure you need to focus. But no amount of focussing, from any distance, will make the emissivity of shiny copper any better, or improve the temperature measuring accurscy.
If you poke the germanium lens one inch away from the copper, and focus perfectly, you'll be measuring mostly the reflection, namely the temperature of the lens itself, not the temp of the copper. Try it.
OK, common sense: look in a mirror. You see your face, not the mirror. Get closer; you still see your face, not the mirror.
Try it.
John
Reply to
John Larkin
OK, positively the last time:
IF THE EMISSIVITY IS 0.98, IT CAN'T BE REFLECTIVE IN THE THERMAL IR.
And while you're at it, check your own link for the emissivity of glass. And smooth ice.
John
Reply to
John Larkin
Most pure metals run right around 150,000 k/w per ohm. Brass seems to be higher, something like 250,000.
John
Reply to
John Larkin
I mentioned the flat side because I wanted the sensors to be close to, and so at the same temperature, as the surface. The fins could easily be at a different average temperature.
Thanks for the interesting link. I note that it shows a very common, inexpensive material, black cloth, with an uncommonly high emissivity: 0.98. With this information, I'd change my suggestion to using a flattish copper block (highest possible thermal conductivity) of a size to take up the viewing area of the IR meter, holes and sensors as before, and with a piece of black cloth glued to the surface. I think the whole thing would be inexpensive and fairly accurate. -- John
Reply to
John O'Flaherty
You just made one, fuckhead.
Reply to
The Great Attractor
You don't get it. If the surface (read that word carefully, idiot) is prepared correctly, a 0.98 emissivity is achieved, and AL makes an EXCELLENT black body source, and it is used in the industry EVERY DAY.
So fuck off, you goddamned retard.
Reply to
The Great Attractor
Yet you complimented HIM for posting it.
Nice reply to me. I really enjoy helping someone out, and then seeing them complimenting someone else for it. Thanks.
Reply to
The Great Attractor
Similar to imagery. One should always take the highest resolution shot possible, so that it can be used in any circumstance form a low res paste to a hi res utilization.
Calibrating an instrument should always involve a known source that is of a HIGHER resolution that the instrument itself is.
If a source that equals the instrument's accuracy is used the error level in the two can chain together. In fact, it is termed as "chaining error".
Reply to
The Great Attractor
It wasn't for me personally. I was concerned about anyone who may not have seen his posts before. Since he seems to specialize in lame insults and counterfactual statements, I don't read his posts much anymore. When someone replies to him, I may read the reply. Someone new to the group, however, may not know this about him.
Reply to
MooseFET
How about a simple warning post, once a week about the losers who spread false and dangerous info?
Reply to
Michael A. Terrell
One of the local news groups I used to frequent had a monthly FAQ posting. There was an unoffical "keeper of the FAQ" who would edit it from time to time and post it about once a month unless it was raining or too sunny that week.
It worked moderately well. From time to time a newby would jump in with a post before reading it and get gently roasted over the open flames. When spam ads were posted we would have a little competition to see who could write the best parody of it.
Reply to
MooseFET
You really need a set of temperature standards. Temperature standard equipment is expensive.
On a laser temperature reader, there is the EMS "emisivity) factor. You must set the EMS of the reader to be proper for the type of object you are measuring. If the EMS is not adjustable on your reader, then the reference object must be of the correct colour and type of material to be referenced.
If your reader is expensive to replace, I would suggest you send it to a calibration lab that can check these types of units.
A crude way of checking the temperature accuracy is to use ice water with crushed ice, and measure the water. This should read within about 0.5 C under ideal conditions. You can boil some water, but the borametric pressure facture must be considered. This should be able to reference to within about 0.5 C. The water must be purified water. Tap water will have minerals in it, and its boiling point will be effected.
Jerry G =====
Reply to
Jerry G.
That is your specialty, you retarded fuckhead.
Reply to
The Great Attractor

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.