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On Oct 5, 2015, at 7:17 PM, John Clement <clement@hal-pc.org> wrote:
I have seen that old bar magnets tend to be weak the next year and need some
refreshment. We didn't have new bar magnets. The commercial magnetisers
worked well.
John M. Clement
Houston, TX
-----Original Message-----
From: Phys-l [mailto:phys-l-bounces@www.phys-l.org] On Behalf
Of Bernard Cleyet
Sent: Monday, October 05, 2015 4:03 PM
To: Phys-L@Phys-L.org
Subject: Re: [Phys-L] magnetic field reversals
On 2015, Oct 05, , at 13:13, John Clement <clement@hal-pc.org> wrote:
Old bar magnets do not hold theirfrequently
magnetism very well, so you have to use a magnetizer fairly
on them. I would say that mususe of the magnetizer may bea real possibility.
I did not always have access to a magnetizer so I wouldcarefully use
ceramic magnets to "refresh" the bar magnets.
antique bars softer than alnico?
Ceramics very approximately 5X alnico.
https://en.wikipedia.org/wiki/Coercivity
https://en.wikipedia.org/wiki/Coercivity
bc
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