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I Forge Iron

Non-contact infrared thermometer


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...troubleshooting on engines...I've seen mechanics use comparative temperature measurements of each cylinder can help quickly diagnose some problems.

One made the short-list for Christmas presents last year but for now I stick to tempil-sticks and spitting on the work :) spit sizzles nicely = 250 degree preheat...spit bounces off = 450 preheat. It's more accurate than you might think.

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No
But a good shop tool. I check electrical breaker, ballast and wire temps in trouble shooting.
Also in the shop, bearing, platen temps on the grinder.

A diesel mechanic gave me mine, he was having a new HVAC system installed in his home and used it to check the hot air at the registers.

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I use process thermometers for photographic chemistry. The chemistry has 1*F latitude and the thermometer can handle that very well. One order of 3 glass process thermometers had all three giving a different reading (almost 4*F total difference). All were sent back and I insisted on 3 thermometers that MATCHED in temps. I now prefer the dial thermometers that have been calibrated back to my glass thermometers as a standard. Even very good mercury thermometers do not agree with each other.

The hand-held infrared thermometers I use show accuracy to 0.1*F on the scale but have an accuracy of 3*F in the literature. Go figure that one out with a pencil and paper. For what I use it for, 5-10*F is close enough and it works for that purpose.

I see no reason why the hand-held infrared thermometers could not be used to gauge drawing temp if used properly, that is used within the thermometers temp range, used within the measurement field of view, and on a non-reflective surface, etc.

This thermometer is a device that registers the last temp sampled and will always register behind the true reading. Add to that the time to move to the quench tank, the time to actually start the quench, and adjust as needed to get repeatable results.

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the real story on ir thermometers.

they are work by measuring the infrared radiation given off by what you what to measure.

every different colored object and different surface texture change its emissivity. the emissivity is a measure of how much IR is radiated by a given object.

to be accurate you need to know the emissivity of the object you want to measure. one way to get this is to measure the temperature of the object and set the IR thermometer to match.

for higher temperatures ( forging) the cheap ones dont work and the better ones measure a different wavelength of light and are $1000 and up....and you still need to know the emissivity.

the IR thermometers are easiest for looking for hot spots where the absolute temperature doesnt matter or in a production setting where each part measured is the same..........

sorry to be long winded..maybe 3 cents worth:)

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Your right about the higher priced/quality one's, the one I have was $1500, we compared it with the cheap one's in the $100-$500 range and the accuracy and even consistency was clearly not there in the cheaper one's.
One thing to keep in mind with infared temp measuring is that they do not read accuratly if the surface is reflective.

welder19

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The higher priced units are more reliable over time. The higher priced units can be lab calibrated whereas the lower proced units are generally not sent out to service centers for calibration. the cost of calibration is often greatert than the cost of replacement. In the field, most sample points for IR readings are predetermined (same place every time) and they are coated to be non-reflective. Reflective surfaces give erronious readings. In the higher Temp ranges (forging) the low price units are usualy well out of range. The IR hand held units are great for maintenance troubleshooting (hot spots) such as would be found on loose electrical feeder terminations, faulty line shaft bearings or insulation failures on uptakes or HVAC distribution systems.

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Using a dual wave length IR pyro will eliminate the emissivity issue...and a lot of money from your wallet. Go down to the welding supply store and buy a few Tempil Stix. These are temperature indicating crayons that are 1% instuments, meaning they melt at a temperature within 1% of the actual temperature. At 1000F, they would melt roughly between 990F and 1010F. The IR pyros are usually 3% instuments. I used a Tempil Stix to check the calibration on my $2000 IR pyro. Tempil Stix are about $10 for each temperature.

Edited by mod07
math error corrected
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