Strengthening magnet connections

[Skywrath]

After a while, I noticed that the magnets aren't strong as the used to be. I typically buy 2x2 neodymium magnets, but then eventually they become loose. Is there any way to make the connections strong again? 

[Xenith]

Unless you've somehow heated them to above 570°C, magnets shouldn't be weakening (over a human life span). What grade (N42, N52, etc) magnets are you using? The higher the N value the stronger the magnet. 

 

To 'remangetise' them, with my lack of knowledge you'd have to melt them then let them cool to below aforementioned 570°C while in a strong magnetic field to take on it's properties. Not really pratical at home. 

 

Or dig them out and add a second magnet behind. 

[WarriorFish]

Yes, while I'm far from a magnet expert I don't think any ordinary use should see the magnet strength weakening. It depends on how the magnetising is done but is it possible that some of the strength of the bond is from elsewhere? For example on embedded magnets often some of the plastic and paint on top is what helps keep a tight join, so could this be the difference? Pictures might help

[GreenScorpion]

Traditional magnets can be easily demagnetized, but neodymium one are not easy to weaken and their natural degradation would typically take something like 500 years if I remember correctly. If that is truly what happened you might want to check where you store/transport the model, because it might be a safety hazard.

 

As WarriorFish mentioned it might be the supporting material that is causing issues, rather than the magnets themselves.

[Skywrath]

@Xenith, I wouldn't know. The magnets I got were these ones.. 

https://www.ebay.com.au/itm/Rare-Earth-Strong-Magnet-Disc-Round-Cylinder-Neodymium-N-50-10mm-x-2mm-1mmm/293210104384

 

Says N50, not sure what that means. However, how would you dig a magnet out of a model without completely destroying his arm in the process?

 

@WarriorFish, I'll have some pictures soon.

 

@Greenscorpion, what do you mean by a safety hazard? The hole wasn't drilled in that deep, there is still some of the magnet showing through the inside of the joint.

Edited August 6, 2020 by Skywrath

[Captain Coolpants]

What might have happened, is some glue or paint could have been on the magnet ends/connections, causing a bit of friction, and thus not moving around as easily. Over time, the thin layer of glue/paint had probably worn away and isn't keeping things in place as well maybe?

[GreenScorpion]

@Skywrath: I meant that anything that would demagnetize a neodymium magnet would certainly be hazardous to a person, so safety hazard in that regard, which hopefully shouldn't be the case.

 

As Captain Coolpants mentioned, if it is not the supporting structure it could be glue or debris making it less connected, dust as well, if you stored unconnected might also be an issue. Cleaning it up a bit with a dry cloth should allow you to confirm if that is the case.

[Imren]

 

@Xenith, I wouldn't know. The magnets I got were these ones.. 

https://www.ebay.com.au/itm/Rare-Earth-Strong-Magnet-Disc-Round-Cylinder-Neodymium-N-50-10mm-x-2mm-1mmm/293210104384

 

Says N50, not sure what that means. However, how would you dig a magnet out of a model without completely destroying his arm in the process?

 

@WarriorFish, I'll have some pictures soon.

 

@Greenscorpion, what do you mean by a safety hazard? The hole wasn't drilled in that deep, there is still some of the magnet showing through the inside of the joint.

 

 

I have removed glued in magnets before. The cleanest and neatest way to do it without ruining the piece it is glued into is to use a pillar drill. Assuming you're using cylindrical magnets;

 

1. If you haven't varnished the paint job on the piece I strongly recommend to do so and have it dried completely.
2. Affix the piece in the clamp at the pillar drill "receptacle" so that the magnet to be drilled is facing up vertically, best to clamp the piece with soft rubber sleeves on the clamp faces so that you don't ruin the paint job and deform the piece. Gently, pull a little on the piece to make sure it is affixed in the clamp.
3. Install a drill bit of the same size as the diameter of the magnet to be drilled, also make sure the drill bit is of the type suitable for drilling steel.
4. Without having the drill powered on, pull down the pillar drill arm and do a couple of dry runs to check that the drill bit moves down and touches the magnet in a centered and aligned way.
5. When happy with the alignment, power on the drill and pull gently down and engage the drill bit and drill away the magnet, when doing this, make sure you pull gently, and slowly don't put much pressure on the drill bit, let it drill slowly, otherwise you will heat up the magnet and melt the piece (plastic or resin). I suggest to stop half way and check the drill progress and let the drill bit and what's left of the magnet in the piece to cool off.
6. Drill down to the end of the magnet, you will see this as the drilled out cuttings start to be plastic/resin instead of metal.

I understand that a pillar drill is not easily available everywhere, most mechanics workshops will have one. Another option if you can't access a pillar drill is to get the dremel miniature pillar drill stand that converts your dremel to a pillar drill.

 

 

Makes sure you use safety goggles when drilling magnets with power tools and also make sure you go slow and easy without much pressure on drill bit while drilling to prevent overheating.

 

Good luck! :)