[TheForge]magnet Q.

[Roger Olsen]

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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