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dumb_password_loser t1_j5opqcs wrote

Reply to comment by Appaulingly in Why does hot air cool? by AspGuy25

Yes, he just sees a colder environment (assuming door is open) reflected on the metal.

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Detectorbloke t1_j5oq3uv wrote

In addition: There's special paint to measure the temperature of normally reflective surfaces.

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AbnormalMapStudio t1_j5pl9jf wrote

Even easier, you can buy emissivity labels (also called IR labels) and just slap a sticker on.

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dr_reverend t1_j5rb0ol wrote

Even easier. Just use some masking tape.

Recommended up to 100c but I doubt 105c would be a problem.

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Lampshader t1_j5rzle5 wrote

The FLIR sales rep recommended black electrical tape when I asked about this.

I dunno what its melting point is but 98% of electronics workbenches will have it within arm's reach already so it's got that going for it

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bella_68 t1_j5s8tpz wrote

Idk how hot a car gets when sitting in the sun but it was hot enough to melt the glue on the electrical tape covering my steering wheel. Interestingly, the glue was liquid and the liquid was everywhere but the tape was still on the steering wheel because the way it was wrapped and the fact that the glue was also still there to some extent.

Unfortunately for me, I get a rash anytime I touch glue

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ArchitectOfFate t1_j5u5knj wrote

The tape itself has NEC standards regarding when it melts and burns, and is designed primarily to melt unless exposed to really extreme temperatures. There’s usually a rubberized or vinyl part of the tape that can turn it into a sticky mess. Good electrical tape shouldn’t have problems at “normal” temps, but on a hot day in the south/southwest a car can get upwards of 150 degrees F, which is pushing it even for the good stuff.

Humidity also doesn’t help and can cause some glues to break down faster.

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VoilaVoilaWashington t1_j5vaa02 wrote

> The tape itself has NEC standards

Which is probably not true of random black tape people buy at the dollar store.

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ArchitectOfFate t1_j5vfsry wrote

Exactly. I didn’t want to accuse OP of buying cheap tape, but proper electrical tape will be clearly labeled as electrical or electrician’s tape, will have the NEC standard on it, and costs $3-$5 a roll unless you’re buying in bulk.

And even then the minimum is 170 degrees. 3M and a couple other companies certify their vinyl tapes above that, but one that’s barely compliant could still get hot enough in a hot car for the glue to start to soften.

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BeetsMe666 t1_j5ug11a wrote

I am a refrigeration mechanic and have had to inform far too many restaurant operators about this fact.

They log the temps in the equipment taken by an ir gun, and they are all over the map. The most consistent recording is done with a probe thermometer in a bottle of water.

Too many employees don't question the reading and just log the number that is far out of range.

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SXTY82 t1_j5p8cb0 wrote

The first time I took a look at a window with my thermal camera I could see the reflection of myself in the thermal image but not in the window itself.

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ThisTooWillEnd t1_j5ppwaq wrote

I've been playing with a thermal camera and not only do I observe what you're describing, I also clearly saw my reflection in a tile wall with the thermal camera.

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Dusty923 t1_j5pj1j7 wrote

Glass reflects different wavelengths of light differently. House windows may also have an infrared-reflective composition or coating (for more efficient cooling in warm sunny weather).

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Denamic t1_j5rocnx wrote

Thermal cameras use IR. IR, being light, bounces off reflective surfaces.

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zebediah49 t1_j5s0zx3 wrote

The relevant point is that visible light will happily go through a normal glass window, whereas long-IR will not. Windows are opaque (and pretty reflective) to thermal cameras.

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