What adhesive should I use on rare earth magnets?

Discussion in 'Replica Props' started by jason1976, Apr 29, 2012.

  1. jason1976

    jason1976 Sr Member

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    Well it's pretty much like the title says. I have some very strong, smooth, rare earth magnets I would like to use on some of my projects. (mostly resin kits, but some metal bits too) and before I waist a lot of time ,and money on the rong glue, epoxy, I thought I would ask here.

    I mean, they are smooth, so most adhesives wont stick will to them without ruffling them up a bit, but I don't know who that will effect them.

    Their quite strong, so I'm also afraid repeatedly pulling them apart would put too much stress on the adhesive.

    Anyway's, and info, would be great.


     
  2. Rebelscum

    Rebelscum Sr Member

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    I can't think of any adhesive that you can use for this purpose. Eventually, they all give it up.

    This is why magnets are generally embedded or a magnet with a countersunk hole is used to mechanically attach it.
     
  3. CynderBloc

    CynderBloc Active Member

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    Wait, I'm doing a project at the minute where I used Neodymium magnets. I countersunk them, leaving them about 3mm below the surface, glued them in with epoxy and skimmed bondo over the top

    Is there something I don't know? Like rare earth magnets and epoxy causing some sort of reaction, because they seem fine to me....
     
  4. JBReplicas

    JBReplicas Sr Member RPF PREMIUM MEMBER

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    when I fitted magnets to my War Machine helmet I drilled into the pieces with a drill bit that was roughly the same diameter as the magnet, then test fitted the magnet by dropping it into the drilled hole to see if it sat 'flush' or flat with the contact surface, once I was happy with that I simply used a small amount of P38 or Bondo filler in the hole and then pressed the magnet in, once the bondo cured it was solid and not going anywhere, I guess epoxy resin would work the same, also remember that rare earth magnets are strong and they dont have to be 100% touching to get a good solid 'contact' Good luck
     
  5. Michael Bergeron

    Michael Bergeron Legendary Member RPF PREMIUM MEMBER

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    I used gorilla glue on my restraining bolts and they've held up fine for a couple years now.
     
  6. CynderBloc

    CynderBloc Active Member

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    That's very true, with mine they're approximately 10mm apart and still have enough force to hold on a piece that weighs about 2kg, yet still easy enough to be separated
     
  7. exoray

    exoray Master Member

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    That is the best answer, they all will fail generally, but this page gives a few suggestions that work OK

    K&J Magnetics Blog
     
  8. jason1976

    jason1976 Sr Member

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    I actually did do the bit, with drilling a hole, gluing the rare earth magnet in, and covering it with bondo, a few years ago. It looked great, and the magnet is never coming out of there, but I must have put it just a little too deep, or something because the pull I'm getting from it, when I put another magnet, or a piece of metal over that spot, is really week. :(

    The other issue is. One of the projects I'm working on, has too pieces of sheet brass. I need to mount a magnet to on piece, and a piece of sheet stainless steel to the other. I certainly can't counter sink that, and cover it with dondo, the brass is like 2mm or 3 mm thick. and the out side of it when it's close has to be pristine.

    The gorilla glue is a good idea though. I have heard a lot of good things about that stuff, and I have been wanting to try it.
     
  9. Rebelscum

    Rebelscum Sr Member

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    K&J is a great resource. The have a newsletter that's always full of interesting magnet uses, tests, and general information.

    How your application uses the attraction during separation, and the number of cycles can have a great impact on its success.

    Pulling the magnet straight away from what it's attracted to requires the most effort. If they are touching, it's the strongest bond. Farther away, it's less, by a lot. If you can separate them across the axis, the effort goes down very fast.

    They also come in a magnificent number of sizes, which affects strength. Something I try to do in applications is never use more magnet than needed for the job.
     

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