Can a TMP36 as a LPM Meter Sensor?

[Benm]

Stealth aircraft 'paint' actually has very good emissivity for IR, but has a specific structure that prevents it from being reflective in the microwave spectrum.

In general the visible color of paint does not tell you that much about the IR emissivity of it. Radiator paint is usually white in the visible spectrum but black in the IR. Black paint often has a good IR emissivity, but there are exceptions there as well. I suppose the best way to find out it to simply test it - paint somehting of known temperature with it and see how the IR readings turn out.

 

[AngelG]

I didn't take of this paint when I had the opportunity, so the possible candidates are:
1. Heat resistant paint 650°C - Auto-K by Peter Kwasny GmbH - German paint
Pros: forms thin layer - 7um; heat resistant; Obtainable - I can get it for ~ 8 USD;
Cons: no data for thermal emissivity; doesn't cure on room temperature - needs at least 250 C.

2. Rust-Oleum 241169; Pros: heat resistant - 648C; the US eqivalent of the above ?
Cons: no data for thermal emissivity; unavail. in EU;

3. T.B.D.

 

[Benm]

The emmisivity being unclear could be a problem, but it's something you can check using an IR thermometer or temperature sensor quite easily: Just paint part of something of good emissivity with the paint and see if it reads a different temperature from an untreaded part at equal temperature.

If it requires 250 celcius to cure/dry that isn't a huge problem either. Most domestic cooking ovens go up to this temperature when set to about maximum, and it probably will cure if you reach only 225 but just take longer. You could even turn on the grill, though that might get too hot when the material is close to it (good test for thermal handling though).

 

[AngelG]

The emissivity can be software tuned, but it is required to be at least 0.50. With 0.1 we'd get prevalent noise, especially for low temperature differences.

Status: the #1 spray is ordered, because I found it easily obtainable and with thinner layer. If needed, 2 layers of it won't hurt.
I expect it on Monday.

Since we 're going to create a building manual, I'd warn the users, that this thing is going to smell. So if they decide to use the cooking oven, they should be prepared for smelly stuff and the most important - don't do this if you have a wife and she's coming home.
The spray contains petrol products, so I expect that it'll stink during the heating. I'll use a party grill like this: Party grill KP 08 on my balcony. It uses IR emission to heat the things at small distance, so if it's heated to 800-900K (it becomes red), our object will certainly reach lower temperature (under it's maximum of 650°C). Still it's not a good thing to heat it too fast, so in phase#1 - "drying" the grill will be turned on, then off before it gets red.

I negotiated with my colleague / chief of another department to get access to a certified-calibrated "thing" which they'll use to measure the artificial "solar" radiation per square centimeter. To me, this sounds like a bit overpriced LPM. Too bad, that they don't have it yet.

I'm still not so sure in the success of this project, but we'll see

 

[Benm]

Thanks for keeping us posted, it will be nice to find out how well these coating options actually work.

As for ovens, solvents and such: I'm not really sure what they use as a solvent, but it's probably a good idea to have some ventilation going. Doing it outdoors is ideal if you can.

For small surfaces that would be all, if you want to coat larger surfaces there might be a problem if the solvent is flammable. I'm not sure if it is or is not, but it is something to consider before putting a large painted piece into an oven, especially an electrical one with a thermostat that might spark