Had color go bad in the cup

[mrex]

I have two IR thermometers, The one from Harbor frieght reads 20 to 25 degrees lower than the craftsman. Believe the one from Harbor frieght is the one that is off. Was burning plastic trying to get it to 350. The one from Harbor frieght is easier to use so I just adjusted to 325 as a target. Guess I need to buy a thrid one from wally world and double check this.

[andrewlamberson]

There are a number of threads on thermometers and why you should NOT use an IR thermometer. There is no way you are going to get a good reading using an IR...not the least being they measure only surface temperature (and the center of the liquid is MUCH hotter) and IR thermometers are for measure temperature on a solid...NOT a liquid and the "temperature" will vary based upon the color of the material, it's composition (metal and wood will read differently) and a host of other factors.

I would not surprise me in the least that your IR thermometer would read 320 (surface temp) while the center is burning at 375+ on a good digital thermometer.

At work, we only use IR thermometers to measure the temperature of equipment...and they are calibrated using a digital thermometer. Any liquid is measured with a digital probe thermometer.  As I've mentioned before, my Daughter is a Microbiologist and she can ONLY use digital thermometers are work. In a couple of my posts I've mentioned the one she uses...that you can but from Amazon for under $20 !

Here's the link: http://www.caneycreekmolds.net/index.php?topic=1182.msg7170#msg7170

Put digital thermometer into the search box (just below the CCM logo on the top right) and there are a bunch of threads that talk about plastic burning, digital thermometers, plastic continuing to cook for up to 1 minute after it comes out of the microwave etc.

[Billmo]

Andrew,
I never got around to thanking you for recommending that thermometer.  I got mine a couple weeks ago and have to say I am very pleased with it.. I like the fact you can calibrate it and give yourself a pretty accurate readong every time you take the temp of the plastic..

Thanks Again..
Bill Mo

[hawgthumper]

Here's something else to think about. When you first pull the cup from the microwave check the temp, then stir, then check it again. I promise you that second reading will be higher every time. Your initial heating was just a little off is all that happened. This is honestly why I despise using a microwave to heat plastic. It is the absolute easiest way to burn plastic. I'll use the presto every time if I can. Much more consistent heat even if you're hand stirring and you can adjust the temp much easier. I know the micro is easier especially for smaller batches, but I still don't like it much. JMHO

[412BaitCo]

Here's something else to think about. When you first pull the cup from the microwave check the temp, then stir, then check it again. I promise you that second reading will be higher every time. Your initial heating was just a little off is all that happened. This is honestly why I despise using a microwave to heat plastic. It is the absolute easiest way to burn plastic. I'll use the presto every time if I can. Much more consistent heat even if you're hand stirring and you can adjust the temp much easier. I know the micro is easier especially for smaller batches, but I still don't like it much. JMHO

X2
I generally see at least 20-30 degree difference after stirring.