11-09-2005, 11:35 AM
If there are any physicists out there, jump into this one, but I think (I said think, but I'm pretty sure) radiation and emmissivity are not the same. Temp guns measure Infrared emmissivity, which is altered by anodizing colors (read the booklet that came with your gun). Radiation, which deals with heat transfer doesn't care what color the metal is, unless the color process/material somehow acts as an insulator.
If you really get into IR emmissivity as a measurement device, you have to take factors such as ambient temperature into account. Our hobby temp guns are just "rough idea" devices, not precision scientific instruments. You get bigger variation in readings based on the accuracy of where you point it at the engine, and how far away you are from it. It's hard to do it exactly the same every time.
And to Bruce's point about resetting the E factor, which you can do, you do have to consider if all of your engines are (insert your color here). If not the readings will be off on some of your engines. But the real question will be "By how much?"
To learn more, go here: http://www.temperatures.com/eindex.html
or your local ITT geek hangout bar.
If you really get into IR emmissivity as a measurement device, you have to take factors such as ambient temperature into account. Our hobby temp guns are just "rough idea" devices, not precision scientific instruments. You get bigger variation in readings based on the accuracy of where you point it at the engine, and how far away you are from it. It's hard to do it exactly the same every time.
And to Bruce's point about resetting the E factor, which you can do, you do have to consider if all of your engines are (insert your color here). If not the readings will be off on some of your engines. But the real question will be "By how much?"
To learn more, go here: http://www.temperatures.com/eindex.html
or your local ITT geek hangout bar.