Reply With QuoteUnlikely, you take your watch off, put it in the tray and it goes through an X-Ray scanner, not a magnetic scanner that you walk through or body searched with.
A relative just had his timepiece assessed as having been magnetised. It is an IWC Portifino and the watch had been through at least 20 security scanners throughout China on a recent work related trip. I am guessing that this was the problem, but in truth is there a real likely hood of this happening? Has anyone else experienced something similar? I suppose you could ask the security people to inspect it outside the scanner and pass it that way so as to avoid a replication in future - I mean it would be a shame to have such a nice watch that can't be worn overseas.
Unlikely, you take your watch off, put it in the tray and it goes through an X-Ray scanner, not a magnetic scanner that you walk through or body searched with.
Of course - good point. I wonder how else it might have been magnetised? I wonder how strong the magnetic field would need to be to create this issue?Originally Posted by rob-vicar
Last edited by Ozyjohn; 4th February 2015 at 11:46.
Are you using iPad?
As already said, unlikely through an X-Ray machine but if he walked through the magnetic scanner with the watch on his wrist he may well have been stopped, manually scanned with a wand and let through. So possibly scanned twice on each occasion?
I don't know exactly how these magnetic scanners work, but I'd have thought that they function more like a degausser than a magnetising device.
I had a watch get magnetised for not reason I can figure out. Does anyone happen to know some common things that can cause magnetisation?
I'll start with unshielded speakers. Many speakers nowadays are shielded, so this is less of an issue than it was, but a lot of hifi speakers are basically just a big magnet in a wooden cabinet.
Why is that?
Speakers, hi-fi and computers etc. are often the culprits for magnetising mechanicals - far more likely than a security scanner.
Possibly this: link?
I agree that it's much more likely to be something in his home or working environment that has magnetised his watch. Too many people go through airports for a problem to go unnoticed. Unless, that is, the Chinese are using something very different from EU, US etc airports.
Thank you for the link. This is exactly what I meant.
Just couldn't find the thread.
Boody hell I put my watches on my ipad so they don't get scratched on the bedside table. And it has one of those covers on it!!! Thanks for the heads up.
Gah! Server ate my reply, but on the plus side it gave me some time to go ahead and try something out.
I was somewhat sceptical of the claimed strength of iPad cover magnets. Neodymium magnets are indeed extremely powerful, but usually the ones used in clasps/covers are tiny, so the overall field strength isn't all that great. This seems obvious from the fact that it doesn't take a huge amount of strength to open an iPad cover. Anyone that's ever tried to pry apart two neodymium hard drive magnets will attest to the fact that the iPad clearly is not using two large magnets, or even one large magnet against an equally large metal surface. For that matter, I've never seen an iPad cover lurch at a nearby radiator, but I've seen hard drive magnets do that.
But, from the picture it looks like there are lots of those little magnets in the case, so I'm guessing that there's only a tiny part of the iPad itself that's magnetic and these extra magnets are to ensure it lines up correctly. They may also serve to prevent the magnetometers reacting to magnets other than the smart cover, by detecting a specific pattern. The screen also acts as a spacer, which may account for much of the loss of strength.
Anyway, I tried to independently reproduce the iPad stuck to the fridge experiment (in my case with a dishwasher as my fridge has a wooden door cover). It worked, with both an iPad 3 and an iPad mini retina (if you try it yourself, the hinge being at the bottom is important!). Not only that, but getting the cover off the metal plate was much harder than getting it off the iPad itself, which seems to confirm the theory about the cover having more magnets than it apparently needs.
So it seems I may have underestimated the strength of the magnetic field an iPad cover is capable of producing. I'm not sure if it will automatically magnetise anything that gets near it though. In general, to get that effect, you need something to move through a constant field, whereas I presume all the magnets are of alternating polarity. Leaving the watch sitting (running) on top of the cover may produce exactly that worst-case scenario and will magnetise the balance wheel, because that is providing the necessary movement through what is a static field. If you simply move the watch around near the cover it probably won't have the same effect, because the polarity will keep alternating. At least, that's my very loose understanding of induced magnetism, which I should point out is very poor indeed, so anyone here with a physics degree can probably correct me on how things actually get magnetised.
This might explain how my watch got magnetised, and perhaps OP's relative too. I'd say the Jury is still out for now. Needs more research, but it seems feasible.
I doubt it can happen too easily though by the simple fact that I think we'd have heard about many more cases by now. I know I have put more than one watch on top of my iPad cover to avoid putting it on a hard surface, just like adesmith (although it's not something I do regularly). I'm sure we're not the only ones to have done this. And since I know I've done this with several watches and only had one get magnetised, it seems unlikely to have been the cause in that case. It could be something that can only happen if you happen to put the watch in just precisely the wrong spot. I do usually avoid putting the watch head over the magnetic bit, so it's possible I was just a bit careless one time. If anyone wants to give it a try, for science...
Reading this on my ipad - I've shifted it into my right hand for safety!
iPad cover definitely magnetised a Seiko 5 of mine and my ZEX, to prove it I put another Seiko 5 on top then checked it and yes magnetised (using a very sensitive geological field compass as tester)
Key is that they run 15-20 secs/day faster than before, check with compass and sure enough, they are now magnetic.
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