Demagnetizer experiment. Seiko 7005 pre & post.

[camrok]

So following a recent discussion about demagnetization I checked out my collection.
Most of my bigger watches gave the compass a bit of a nudge from magnetic north- but the 7005 spun the needle 180 deg.
I resurected a cheap demagnetizer and here are the results.

www.youtube.com/watch?v=QSnVL7n1lwA

[Mr.Jones]

Huh, I guess not all magnetized watches run faster, then?

[bklake]

Can't tell from video but make sure you remove the watch on your wrist next to demagnetizer or you will have to run it through a cycle next.  Learned that one the hard way. 

[3Pedals6Speeds]

Now I really miss my 7005-8052.  I should have never sold that thing.

[camrok]

Apr 26, 2017 6:23:57 GMT -8 bklake said:

Can't tell from video but make sure you remove the watch on your wrist next to demagnetizer or you will have to run it through a cycle next.  Learned that one the hard way. 

I'm pretty sure I purposefully wore Quartz. I did think of that but wasn't sure how far the magnetic field extended. Good advice.

[tritto]

I thought you used a demagnetiser by holding the watch next (or above it) then slowly drawing it away. This sitting the watch on top of the demagnetiser is different. Are there different types of demagnetiser that need different techniques?

[camrok]

Apr 26, 2017 12:51:18 GMT -8 tritto said:

I thought you used a demagnetiser by holding the watch next (or above it) then slowly drawing it away. This sitting the watch on top of the demagnetiser is different. Are there different types of demagnetiser that need different techniques?

Some guy on you tube told me to leave it there for 10 sec then pull it away whilst the magnetized was still on before you let go of the button.
I've seen this replicated on a few vids. I'll look at the science behind it tonight.

[tritto]

Nah, you're probably right. I thought you turned it off before you lifted it away.

[camrok]

Apr 26, 2017 5:09:46 GMT -8 Mr.Jones said:

Huh, I guess not all magnetized watches run faster, then?

I noticed that too.
The 7005 was a pretty extreme example of a magnetized case.
The interesting test would have been to drop the movement out and test the magnetic field.
The other interesting thing was the watch had definite poles. From memory north was closer to 6 o'clock.
So I guess if the case was magnetized beyond the hair spring the watch would run fast or slow depending on which way it was pulling the leaves of the spring? If that makes any sense.

[HiBeat]

Thank you for posting that video. I found it extremely enlightening. The other day I had a 6309 stem that was super magnetized, so I de-mag'd it.

Somehow it ran well despite that.

[Adrian-VTA]

That's the correct process, if you turn it off suddenly the watch will still be magnetised.

Apr 26, 2017 13:19:27 GMT -8 camrok said:

Apr 26, 2017 12:51:18 GMT -8 tritto said:

I thought you used a demagnetiser by holding the watch next (or above it) then slowly drawing it away. This sitting the watch on top of the demagnetiser is different. Are there different types of demagnetiser that need different techniques?

Some guy on you tube told me to leave it there for 10 sec then pull it away whilst the magnetized was still on before you let go of the button.
I've seen this replicated on a few vids. I'll look at the science behind it tonight.

[tritto]

I got a cheap one and tried it on that Silverwave that was suddenly losing time (to no effect). I was surprised to hear the rotor spinning when it was over the demagnetiser.

[Adrian-VTA]

The weight is usually steel, so will be spun around if the main force of the magnet is off to the side.

Apr 26, 2017 17:59:24 GMT -8 tritto said:

I got a cheap one and tried it on that Silverwave that was suddenly losing time (to no effect). I was surprised to hear the rotor spinning when it was over the demagnetiser.