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Dry Compass Needle Making Answered

Hello.  I've been working on a project that I foolishly thought would be fairly simple.  It's a decorative compass, kind of.  The body was simple enough to make, but now I'm stuck on the needle.  I had researched the making of a permanent magnet and thought  the process was definitely do-able, but found out that with such a small piece of metal it's actually very difficult.  Then I did a little more research into compasses and learned that dry compasses do not work the same as wet compasses, mine is a dry compass.                 My question to all of you physicists and engineers is:  is it possible for someone to make a dry compass needle at home and, if so, how?                  I realize I could find a cheapish compass and pirate the needle, and will if I have to, but what fun is that? 

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Kiteman (author)2013-12-30

First, fashion your needle. Say, cut the shape from the metal of a mint tin, including a dent in the middle that will take the point upon which it balances.

Then find yourself a very strong magnet.

Heat the needle with a blowtorch until it glows red, then leave it to cool next to the strong magnet. As the needle cools, its magnetic domains will conform to the field of the strong magnet, giving you a magnetised needle.

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thematthatter (author)Kiteman2013-12-30

cant you just rub the metal against the magnet?

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user

Way back when, you would just bang on steel helmets to make them go the right way.

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Who the compass or the LT holding it?

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The green turtle with the stripes.

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Kiteman (author)thematthatter2013-12-30

It wouldn't create as strong a magnet.

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Attmos (author)Kiteman2013-12-30

Sounds easy enough, thanks. I'll let you know how it turns out.

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caitlinsdad (author)2013-12-30

I haven't tried but a flat steel strip that you run through one of those tool/screwdriver magnetizer/demagnetizers? How big did you need the needle? http://www.sears.com/craftsman-magnetizer-magnet-and-demagnetizer/p-00945021000P

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Attmos (author)caitlinsdad2013-12-30

Cool idea but I don't think it will make a permanent magnet. Thanks for showing it to me though, I've never heard of these and now I might just have to get one.

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Kiteman (author)2013-12-30

First, fashion your needle. Say, cut the shape from the metal of a mint tin, including a dent in the middle that will take the point upon which it balances.

Then find yourself a very strong magnet.

Heat the needle with a blowtorch until it glows red, then leave it to cool next to the strong magnet. As the needle cools, its magnetic domains will conform to the field of the strong magnet, giving you a magnetised needle.

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