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I'm using two thermometers to check the temperature of a bending iron, made from a large piece of aluminum boat mast. One is a cooking thermometer purchased from John Hall with his silicon blanket and metal slats, for use with my home-built side bender. The other is a laser gun-type unit that I bought early on when I was bending sides just on the bending iron. My question is, why would the two thermometers read drastically differently? The laser unit reads far too low compared to the kitchen thermometer when checking the bending iron. The laser unit, though, does read apparently correctly when pointed at various objects, including steel and aluminum tables on sanders which are at room temperature. I seem to recall some limitations in laser thermometers. Am I expecting too much of it? Bruce W.

Can't tell you
first I assume they are both set on F then one thing I learned on the cooking therm. If the battery is low they won't read well. To check this is easy make a pot of boiling water ( 212F ) and see what temp each are reading
that way you know the one that is closest

On a similar note is the variation in readings between humidity gauges. Humidity is an important consideration for many of us. I have 3 electronic ones, actually now 2 because I threw one away yesterday, and 1 of the typical old clockface type. There is about a 12% difference in readings between these.The only way I know to calibrate the reading is with an sling psycrometer. You can buy them online or cobble one together from online instructions, which is what I plan to do today. Hopefully you bought your Halloween candy early so that you still have time to replace what you have eaten!-Bob

Laser thermometers are limited by reading the surface radiance only. But, they're influenced by surrounding conditions and objects. Thermometers meant to be put directly into or onto the object that it's reading will be more accurate than a laser thermometer, because it's reading the deep temperature of the object which is being measured.

Laser thermometers will give you a good idea of an object's temperature. But if you need an accurate temperature, always use a contact thermometer.