What kind of glue to make a magnet adhere to wood?

Question

I've had these two small wooden heart magnets given to me a year ago, but over time, both hearts have fallen off their magnets. They seem to be attached by a thing sheet of some kind of clear glue that obviously can't hold in the long run (it's taken them both several months to fall off).

If there a particular kind of glue I can use to make the magnets hold together for good?

Answer 1

Magnets are notoriously glue-resistant.

There are sticky soft magnets used e.g. for refrigerator magnets, which would kinda work on the glue front, but they are pathetically weak.

You could try two-ingredient epoxy for other magnets; it tends to stick really well to pretty much everything and if it won't, you can practically encase anything with it.

But I believe the best solution would be to forgo the glues and obtain some tiny neodymium magnets with a hole:

These are very strong, so even a tiny one can support your heart, and they can be affixed to a surface with a nail or a screw, making a very strong connection.

Answer 2

Over at Lifehacks SE I was recently introduced to Sugru, a play-dough-like silicone clay that sticks to virtually everything, hardens to a kind of rubber and is intended for small hacks, repairs and similar tasks.

They have a whole collection of projects with magnets on their website and your hearts would fit in nicely.

Answer 3

If there a particular kind of glue I can use to make the magnets hold together for good?

For good could be tough sell but like Joel Huebner says super/crazy glues would work just fine for this. For something this small that would be bearing much stress of weight it should be fine.

If you really wanted to you could use some 2 part epoxy from an applicator but I don't think that is necessary.

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One thing to keep in mind is that some of the wood you might be using would have a finish on it. If you intend to use glue for any surface you might get a better bond if you sand off the finish and get to bare wood. Smooth it off and then glue it. The glue should soak into the grain of the wood.

Answer 4

I use either Elmer's wood glue, it takes 12~ hours to dry. Or I use one of the thicker "super glues"

Answer 5

It isn't clear whether the idea of the magnets was to hold the two hearts together, or these were two cute "refrigerator" magnets. But it sounds like the magnets, themselves, were adequately strong to do their job; the only problem was keeping them attached to the wood.

Those magnets are molded as a flat strip. They're a bit flexible in a long strip, much less so in a short piece, and they want to return to flat. Whether they were attracted to each other or a metal surface, the magnets were flat when in contact (it's the only way they have enough attraction to hold any weight).

They were attached to the wood with double-sided tape designed for attachment to a flat surface. The hearts aren't flat. So the magnets were always trying to pull away, and the tape stuck to the wood better than it stuck to the magnet.

If you glue the magnets tightly to the wood, they won't hold the weight because the whole magnet won't be in contact with the other surface. Attaching the magnet to the wood needs to be done with the magnet flat and something filling the gaps and contours between the magnet and the wood.

If you do it that way, the adhesive will need to bond to both surfaces enough to support the weight of the wood (not much), and tugging on it to pull the magnet off the metal surface it's stuck to, but it won't need insane, super strength. An adhesive that's a bit flexible will do better than one that dries hard, and it won't need as much adhesive strength.

• Elmer's wood glue (Joel Huebner's suggestion), won't stick well to the magnet long term, but it might be a strong enough bond for this lightweight purpose. But it would probably suffer from the same problem as the original sticky tape. A thick layer could fill the gaps, but it shrinks a lot when it dries, so either it would distort the magnet or pull away from it.
• Thick super glue, also suggested by Joel, will fill small gaps, but is brittle, so it would be susceptible to breaking again. There are rubberized super glues that fill small gaps and remain a bit flexible. They would probably work but they're expensive, and overkill for a lightweight requirement.
• Epoxy, mentioned by SF and Matt would probably work, but is overkill for a lightweight requirement.
• Sugru, mentioned by Stephie, would probably be a good solution, but the stuff is expensive.
• A cheap alternative would be a layer of silicone caulk thick enough to fill any gaps when the magnet is flat.
• Going back to how the magnets were originally mounted, they really just used the wrong tape. There is heavy-duty mounting tape that consists of a thick foam ribbon with aggressive adhesive on both sides. The adhesive will stay stuck, and the foam adjusts to the irregularities in the contour.
• Of course, SF's suggestion of attaching a strong, small magnet with a screw won't come off. If you're going to drill a pilot hole for the screw, just drill a larger diameter, shallow hole, and glue in a small, strong magnet for fancier appearance.

Answer 6

If you want to glue a strong round magnet to something with some thickness, it helps enormously to partially recess the magnet. Drill a hole into which the magnet fits quite snugly, slightly shallower than the thickness of the magnet. Then you can use epoxy, or PVA wood glue (or many other glues). This helps because glues in general are far stronger in shear than under tension.

Note that if the surface of the magnet is below the surface of the host material (your wood) it will hold far less effectively. You can use this to your advantage if you only have too-strong magnets but it's hard to tune the effect.