iPhone Compass a reliable way to test for magnetization?

[chicago]

I believe that somehow my Longines Legends Diver got magnetized. When I bring it near my iPhone while the compass app is running, it starts to go crazy... when I move it away, the compass returns to normal. None of my other watches do that. The longines is also running really fast, it picked up several minutes overnight.

So 4 questions for you guys

1) is the iphone method reliable way to see if the watch is magnetized or should i get a real compass?

2) will the cheap blue-box demagnetizers found on amazon do the trick for me? i've never used one before, little confused as to how they work or if they even will work for this

3) could a watch winder be the culprit in causing the magnetization? none of my other watches who went in the same winder are doing the same thing, i tested them all

(edit) 4) Any risk to my other watches from being NEAR the LLD in a watch box while I wait for the demag device to arrive?


Thanks,
Dan

[CFR]

1) Don't know the app so I can't answer
2) You could try, but any watchmaker should be able to demagnitize your watch in less than 10 minutes
3) Higly improbable
4) Your other watches should be fine

I don't know why, but my watchmaker told me that this problem is becoming more and more common. I had a watch magnetized once, but it was - accidentally - placed near a strong magnetic field

[93EXCivic]

I am really curious of the gauss level it takes to magnetize a watch. I would imagine it would take at least a thousand gauss honestly. I work in a magnetics lab every day with magnets ranging for very small to big 3" diameter by .5" thick Neodymiums.

I have never seen a watch be effected except for putting a cheap quartz right on top of one the big magnets and watching it run backwards... I don't wear a watch around the big ones but I have never seen a watch effected by a magnet like you would find in a consumer electronics device.

Compasses in iPhones are very sensitive to magnetic fields so it come be an indication but I wouldn't say that it is proof. I seriously doubt your winder would cause the problem. I imagine if there is a magnetic field from the device it is at way to low to create a magnetic field in the components of the watch and if your watch is magnetized the field is certainly too low to effect your other watches.

I should really do some tests on it. I have access to magnetic scanners and large magnets

Sent from my iPhone using Tapatalk

[CFR]

If you follow the link below, you'll see that Longines will demagnitize your watch for FREE (page6/7), if you take it to a service center

http://www.longines.com/Content/Cust...%202014_en.pdf

[OrangeSport]

I assumed that the app would be GPS based.

I don't think it takes too much for some watches to be affected. I have heard of iPad covers and laptops doing it before.

Washing machines always worry me, and a Rolex AD warned us that some freezers cause problems too.

[93EXCivic]

I assumed that the app would be GPS based.

It isn't. It is a chip that uses magnetic fields. If you take a magnet and put it by the phone you can move the compass around.

[OrangeSport]

Thanks - live and learn..

)

[Nokie]

I have yet to magnetize one of my watches and I can work around alot of stuff that generates decent magnetic fields, so I feel lucky, but not sure why my eyebrows glow at night........

[WWII70]

Yes Dan, this poses a serious risk to your other watches. Send your LLD to me immediately!

4) Any risk to my other watches from being NEAR the LLD in a watch box while I wait for the demag device to arrive?


Thanks,
Dan

[chicago]

So my crappy blue-box demagnetizer came in yesterday and I tried it today on the LLD. Took a bunch of tries but it seemed to eventually reduce the amount of magnetization considerably (at least as measured by my iPhone)

That said, the watch is all of a sudden running slow - its only 5 hours after i demagnetized it and set it, but its already lost 3 (going on 4) seconds after being set against time.gov. That's a loss of about 19 seconds per day if I extrapolate it, which seems to be a lot...

It was running almost a minute/day fast before i demag'd it. So that is an improvement on that front, but losing 20 seconds a day?