[TheForge]magnet Q.

[Steve Smith]

I don't have a clue, Roger. I did find a list of Curie point 
temperatures for different materials. Here are a few (in degrees 
Kelvin--subtract 273 and you have Centigrade):
Iron 1043
Cobalt 1388
Nickle 627
source: http://www.nationmaster.com/encyclopedia/ferromagnetism

etc. So your question is good, how soon do you see effects? It also 
looks like you have a huge effect in the actual temp by what alloy 
you're magnet is made of. I don't think this helps, just more info.

Steve Smith


Roger Olsen wrote:

> So I assume the higher the heat the faster the magnetic loss but when does
> the affect kick in?  100 degrees________300 degrees_________500
> degrees________700 degress?
> 
> Does anyone know the answer to this?
> 
> R. Olsen
> _______________________
> 
> Bruce Freeman wrote:
> 
> 
>>Clearly, when steel goes non-magnetic, if the steel WERE a magnet it
>>wouldn't be afterwards.
>>
>>However, any heating or hammering will reduce or destroy the magnetic
>>properties of a steel magnet.
>>
>>If using a magnet as part of a door latch:
>>
>>First, be aware that those rare earth magnets can be VERY strong.
>>Think pinch-points when using them in a design.
>>
>>Second, you may want to move the magnet itself away from the heat.
>>Imagine, for example, using a horseshoe magnet as the handle on a hot
>>door.  The cooler handle will be less likely to lose its magnetic
>>properties.  But if constructed correctly, this remote handle could be
>>an effective latch for the door, since the magnetic forces will follow
>>the path of the steel.  (Constructed incorrectly, there would be no
>>magnetism to latch the door, however.   Avoid a complete loop.  Think:
>>"horseshoe" shape.)
>>
>>Bruce
>>NJ
>>
>>
>>>>>erik at methow.com 5/13/2004 12:22:50 PM >>>
>>
>>Hey Andy,
>>
>>Ask your friend one other thing about magnets.  I wonder about heat, at
>>what
>>point does it drain a magnet of its magic affects?   I have never used
>>them on
>>fire doors but I know many have.  I have considered using them in the
>>past and
>>I am sure I will again in the future.
>>
>>If I did I would use the 'Rare Earth Magnets' sold by Lee Valley and
>>others as
>>well.  They seem to be about 10 times stronger than the radio shack
>>type
>>magnets.
>>
>>Roger Olsen
>>__________________________________
>>
>>Gladish Family wrote:
>>
>>
>>>>1. I have a number of assorted magnets used for set-ups, mock ups
>>
>>and
>>
>>>>the like...should they be stored separately, carefully aligned
>>>>north/south, to retain max  pull ( suck?) or is it not a problem
>>
>>just to
>>
>>>>toss them in a box with their friends?
>>>
>>>My understanding is that magnets are manufactured by applying
>>
>>overwhelming
>>
>>>magnetic fields (i.e. really really huge!) to a previously neutral
>>
>>chunk of
>>
>>>metal, and that heat or overwhelming magnetic force are the only ways
>>
>>that
>>
>>>magnets lose their pull, other than physical deterioration.
>>>I have a friend who sells magnets for a living- I'll ask him.
>>>Andy G.
>>>
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> 
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