Wot “magnetized” and “unmagnetized” magnets?

Discussion in 'Luthier's Corner' started by Atmospherium, Apr 14, 2018.

  1. Atmospherium

    Atmospherium Member

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    Shopping around for replacement magnets for a P90 pickup, I see some sellers offer “magnetized” and “unmagnetized” options. Can someone shed any light on what this means? Surely “magnitised” is the whole point, and I’m guessing that by “unmagnetized” they’re not talking about selling just a flat piece of metal? :)



    Cheers
     
  2. Atmospherium

    Atmospherium Member

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    And while I'm at it, what are the benefits / drawbacks of "unorientated" (I'm guessing this means it doesn't matter which way you insert it into the pickup) and "rough cast"?
     
  3. Relic61

    Relic61 Well-Known Member

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    Unmagnetized is for those who want to magnetize properly prepared magnetizable material themselves. They can then to some extent determine magnetic strength & direction of polarity.

    An Unoriented Magnet is a magnet that can be magnetized in either direction and has less organized molecular makeup.

    An Oriented Magnet has a more organized molecular structure and they are magnetized with a specific polarity orientation. (they magnetize best in one direction)

    Polished magnets are made in large blocks and then cut to size and polished smooth.

    Rough Magnets are cast individually to size and are left looking rough & or bumpy.

    Hope that helps some. Magnetism is an amazing property & an integral part of our technological breakthroughs bringing about invention like the production of electricity.

    Tesla was fascinated by magnetism & felt that fully understanding its potential would bring about even greater invention.
     
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  4. Adavis84

    Adavis84 Member

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    Just to tack on: the typical bar magnets in humbuckers and P90s will be likely be of alnico alloys 2, 3, 4, 5, or 8. There are others, but these are most common. I assume you're looking at alnico 5 given you have the unoriented option. As far as I remember 2, 3, and 4 are "unoriented" or isotropic by definition. It's 5 and 8 that can be sourced either "unoriented" or "oriented" (anisotropic). (someone please jump in here if I'm misremembering somethng!)

    Don't confuse the magnet's polarity with this property. Bar magnets for pickups of either isotropic or anisotropic composition will still be polarized as you'd expect (IE a north and south direction on each side). In a P90 you'd still need to orient the two bar magnets the correct way regardless of the material from which they're composed.

    There are subtle tonal differences between rough-cast and polished magnets as well as further tonal differences between "unoriented" or "oriented" varieties of the same alloy.

    Google "UOA5 magnet" (unoriented alnico 5) and you should come up with a host of threads from other forums about the tonal variations.

    Substituting an UOA5 for stock polished oriented A5 in a bridge humbucker is one of my favorite tone tweaks.
     
  5. AngelDeVille

    AngelDeVille Well-Known Member

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