Weird magnetic thermo question

[eclecticcottage]

Any idea what would make one lose it's magnatism?? I went to clean up the stove top last night and found that at some point the thermometer has stopped being magnetic! It's not like we took it off the stove or anything over the summer...I'm baffled. Is that going to effect the temp readings? I can't see how, but...I also can't see how it suddenly demagnatized itself sitting untouched on the stove top.

 

[begreen]

High heat?

 

[corey21]

Like begreen said high heat maybe.

 

[eclecticcottage]

It happened over the summer though...I know it was still well stuck on there at the end of the last burning season, and some time over the summer when I cleaned it...DH said it was like that (not magnetic) when he cleaned off the dust before firing it up the first time this season. As far as I'm aware, we only had one overfire and it was near the beginning to middle of last burning season. And that wasn't all that severe, just a faint glow next to the thermo, and we had it under control within half an hour. Now I'm trying to think if I might have set it next to something that might have done it when I cleaned it over the summer.

 

[ikessky]

It happened over the summer though...I know it was still well stuck on there at the end of the last burning season, and some time over the summer when I cleaned it...DH said it was like that (not magnetic) when he cleaned off the dust before firing it up the first time this season. As far as I'm aware, we only had one overfire and it was near the beginning to middle of last burning season. And that wasn't all that severe, just a faint glow next to the thermo, and we had it under control within half an hour. Now I'm trying to think if I might have set it next to something that might have done it when I cleaned it over the summer.

There are lots of times that things happen at home and I tell my wife, "I dunno. I found it like that." I'm just saying.......

 

[pgmr]

See http://www.physlink.com/education/askexperts/ae472.cfm for attractive answers to this repulsive problem.

 

[eclecticcottage]

Well...I am thinking there's NO way heat did it after reading the heat needed to demagnatize it. The stove would be a mess if we overheated it like that.

 

[Sprinter]

Have you seen any strange lights in the sky lately? Any crop circles in your area?

I believe that some materials that can be used in neodymium magnets can have Curie Points in the 300-400° C range. I wouldn't think that a stove top thermometer maker would use them, though... anyway, when such a material cools, it usually regains the magnetic property.

A sharp mechanical blow can demagnetize some magnets depending on the material. Have you been banging on it with a hammer mercilessly?

 

[corey21]

If it was not the heat then higher powers are at work here.

 

[oldogy]

HPFM========Hocus Pocus Fancy Magic going on there. Some may have heard it a bit differently but the magic is the same.

 

[Sprinter]

It happened over the summer though...I know it was still well stuck on there at the end of the last burning season, and some time over the summer when I cleaned it...DH said it was like that (not magnetic) when he cleaned off the dust before firing it up the first time this season. As far as I'm aware, we only had one overfire and it was near the beginning to middle of last burning season. And that wasn't all that severe, just a faint glow next to the thermo, and we had it under control within half an hour. Now I'm trying to think if I might have set it next to something that might have done it when I cleaned it over the summer.

You know, it is possible to lose magnetism if it were exposed to an AC magnetic field. I don't want to hazard a guess about what that may have been, but it's a possibility. For example, if you are familiar with Weller soldering guns, we used to demagnetize stuff (as kids just messing around) by running them through the loop. there are also commercial devices for magnetizing and demagnetizing tools like screwdrivers like this http://www.amazon.com/Magic-Cube-Magnetizer-Demagnetizer-Tools/dp/B003RY6YYM/ref=sr_1_2?s=hi&ie=UTF8&qid=1352506114&sr=1-2&keywords=magnetizer demagnetizer

Edit: Here's a possibility. If you have an older CRT-type TV or a CRT type computer monitor, they have built-in degaussers, which are literally demagnetizers, for the CRT. I really don't know how close you would have to get a magnet to affect it that much, but it's another possibility.