OT Is there a difference between a magnetic car key holders whose box
portion is made of sheet metal, versus one made of plastic?

That is, the magnet is the same. Will a metal container portion
increase the effective strength of the magnet?

In article , NONONOmisc07
@bigfoot.com says...

OT Is there a difference between a magnetic car key holders whose box
portion is made of sheet metal, versus one made of plastic?

That is, the magnet is the same. Will a metal container portion
increase the effective strength of the magnet?

it could be however.,.. one scenario I can think of and it may have
nothing at all to do with it.. Key fobs have sensitive electronics
and programmable keys could be sensitive to magnets ?

Using a metal container would act like using Mu metal, the magnetic
field (flux) could bend towards the case and not have a high reluctance
to the field.

High reluctance would mean the field would be allowed to permeate
through your keys..

That's just a guess of course. it could be just marketing

Jamie

On Sat, 21 Jun 2014 15:16:54 -0400, micky
wrote:

OT Is there a difference between a magnetic car key holders whose box
portion is made of sheet metal, versus one made of plastic?

That is, the magnet is the same. Will a metal container portion
increase the effective strength of the magnet?

Both use a U shaped piece of steel with a magnet inside the U. That
means that the magnetic field is almost entirely between the poles of
the U. You can confirm this by trying to attach some piece of metal
to the back end of the U, where the plastic or metal can is attached.
It won't stick, meaning there's no magnetic field. Therefore, the can
be made of either magnetic or non-magnetic material without affecting
the field between the poles on the opposite side.

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Jeff Liebermann
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