Temp sensing heat gun

[Oznog]

I'd like to combine a heat gun and infrared thermometer, so that it heats only up to a particular temperature and then cuts back on the heat. That's got infinite uses, heat guns are rather troublesome in the way they can quickly melt/burn materials.

I have not seen IR thermal sensors for sale outside of those noncontact thermometers. I supposed it wouldn't be unreasonable buy another one just to gut out, but with no spec sheet or even theory of operation, I don't know what I should do with it.

Anybody got a source on parts or information? Maybe one that's meant to hook up to a Fluke, so interfacing is just about reading a straightforward mV value?

 

[Klaus]

For a very low tech solution you could try these heat sensitive labels or crayons on the heated object. Your finger would switch off the heat gun as soon as your eyes tell from the colour changing label that the target temperature had been reached :wink:

The infrared solution sounds expensive by comparism though, if you'd want to *maintain* a certain temperature, it may be your only choice unless you are happy to use this other low tech solution: Use a thermostatic switch on the area to be heated. They are available up to 150 deg C and can switch 10 Amp.
Klaus

 

[Oznog]

Not what I'm looking for. I want to weld plastic foams, for example (I do this all the time). Both sides need to be air heated to a certain temp without totally melting the foam and pressed together. A sensor cannot mechanically be placed on the surface, and the gun needs to wave over a significant area to boot.

Also, warming PCBs for flowing surface mount paste at home. The preheating needs to be as high as possible without burning the board. Fiberglass is a thermal insulator so hot air or infrared is usually the easiest way to heat it evenly, rather than hot plate conduction.

 

[olly_k]

Whats a matter with an adjustable temperature heat gun? I bought a great one which outputs anything from 40C to god knows what (very hot) with a pot to give fine temperature control. I know you don't see them very often but if you look around I am sure one will turn up!
You could use a normal thermostat to check air temp.
The problem with IR thermometers is that they as well as using a PIR type sensor, also have a thermistor which gives them a reference 'room' temperature. this is why you have to let them acclimatise to a specific area before use. I think you would have problems integrating such a device into a hot air heat gun!
I once left my IR probe near the fire in the living room and when I came to use it to check some newly installed door insulators I was rather upset to see a stupid reading, I think about -25C :shock: I thought it was bust!
It took me a while to realise the heat from the fire had drastically altered the reference temp and made my tester look very faulty :roll:

 

[bmcculla]

digikey.com sells thermopile noncontact temp sensors for $12 each. For a bit more you can buy them with all the signal conditioning circuitry and a nice digital output. The company that makes them is Melexis.

Brent