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Demagnetizer Recommendations


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@Endeavor: -Yes, but your version takes a bit of "skill" to get to work! :)

The versions with coils work with distance attenuation - the field gets weaker as you move the part/movement away from the coil.

The automatic ones often use current attenuation, the field gets weaker around the part/movement  so the part can be still.

 

img_02.jpg

 

(picture from: https://www.j-ndk.co.jp/en/product/index_datsuji.html)

 

In my version a capacitor is charged (takes abt .3s) and is then then is used in a parallel LC-circuit that takes abt. 50ms for the field to go  from fully charged to zero. (depending on capacitor values, voltage and size of coil).

The biggest plus is that you do not need to lift/move the movement in the coil/field and the results are equal time and time again! :)

Edited by RCDesign
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Thank you for the additional information :)

I now also understand again how the coil / capacitor circuitry works. Where I was initially a bit puzzled about was what kind of capacitor was used and therefor whether the AC was first converted to DC. Now knowing the L/C principle again, it may be wise to put up a schematic of your system with the details of the components. We don't want somebody to grab an electrolytic capacitor and "blows the place" or seriously harm himself....... The modern electrolytic capacitors do rupture, or have a relief-valve, but the old ones don't, and they take off like a rocket when connected to AC or hooked up wrongly to DC. (don't ask me how I know :biggrin:)

So if you have a simple schematic of your system with the components details, then at least that part is covered ;)

Thanks again!

 

Edited by Endeavor
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The other thing that is needed when playing with magnets and watches is a way of figuring out if your watch really is magnetized or not.

So there's the old-fashioned way with a compass image attached for how to do that. then a link to a free app for your phone from a company that wants to sell a really expensive demagnetizer.

https://www.lepsi.ch/watch-demagnetizer/

 

Check the magnetic field.JPG

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  • 2 years later...
On 5/19/2016 at 7:17 AM, oldhippy said:

Link doesn’t work. Could you get a pic?

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  • 1 month later...
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  • 11 months later...

I have an old (1940?) demagnetizer. I’ve read about how some of these old ones are maybe too strong to put complete watches through, but never had an issue until yesterday: I put a complete cased watch in the hole, pushed the button and then slowly pulled it out, like I have 100’s of times. This time, the roller jewel actually got knocked out! When I took the back off the watch to see what happened I found it (luckily) on the ledge of the case! Looks like these strong demagnetizers can be too much sometimes?

I better buy a less aggressive one for complete watches. Anyone else ever see such a thing?

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1 hour ago, Woolshire said:

I better buy a less aggressive one for complete watches. Anyone else ever see such a thing?

No need to buy another one, just start a bit more far away from the object. However it's also true some demagnatizers are made for mechanical shop use not watchmaking. 

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4 hours ago, Woolshire said:

This time, the roller jewel actually got knocked out!

You didn't tell us what kind of a watch this is or how old it is? I think you'd find under normal circumstances it would take a heck of the impact to knock a roller jewel out. Very common on older watches that they become loose with time so anytime you're working on older watch your always supposed to check the roller jewel because quite a few times are on the verge of falling out anyway.

Watch companies are interesting for their recommendations. Omega is concerned of having too strong of a magnetic fields but then there are so looking at wristwatches. They don't have to deal with the things we deal with in the field that are often bigger than a wristwatch. Then there also looking for a tool that will tell you if the watches magnetized because compasses really aren't reliable.

I snipped out an image of unacceptable tools strangely enough they don't show ever using the Elma Antimag? Then another image of the important points kinda hinting at the magnetic field for removing magnetism has to somehow be really special and multi-directions. Which is interesting if you look at the instruction sheet for the Horotec Magtest What they show looks exactly like the same kind a magnetic field should get from the Elma Antimag .

https://www.witschi.com/en/products/teslascope-2/

http://horotec.ch/news/MSA19.910/102/lang/2

 

Omega unacceptable tools for magnetism.JPG

Omega important points magnetism.JPG

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  • 1 month later...
On 1/29/2022 at 6:28 AM, JohnR725 said:

You didn't tell us what kind of a watch this is or how old it is? I think you'd find under normal circumstances it would take a heck of the impact to knock a roller jewel out. Very common on older watches that they become loose with time so anytime you're working on older watch your always supposed to check the roller jewel because quite a few times are on the verge of falling out anyway.

Watch companies are interesting for their recommendations. Omega is concerned of having too strong of a magnetic fields but then there are so looking at wristwatches. They don't have to deal with the things we deal with in the field that are often bigger than a wristwatch. Then there also looking for a tool that will tell you if the watches magnetized because compasses really aren't reliable.

I snipped out an image of unacceptable tools strangely enough they don't show ever using the Elma Antimag? Then another image of the important points kinda hinting at the magnetic field for removing magnetism has to somehow be really special and multi-directions. Which is interesting if you look at the instruction sheet for the Horotec Magtest What they show looks exactly like the same kind a magnetic field should get from the Elma Antimag .

https://www.witschi.com/en/products/teslascope-2/

http://horotec.ch/news/MSA19.910/102/lang/2

 

Omega unacceptable tools for magnetism.JPG

Omega important points magnetism.JPG

That’s interesting… Which demagnetizer does Omega recommend then?

I’ve read elsewhere that the Greiner is supposed to be strong enough to demagnetize a cased watch, but wouldn’t have thought it could be too strong…

In your opinion is Omega being overly cautious? Most demagnetizers don’t exactly quantify exactly how powerful they are, so we would have no way of knowing either…

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4 hours ago, ifibrin said:

Which demagnetizer does Omega recommend then?

If you look at the section you quoted there are two links those go to what they recommend. We do get in the image I snipped out hinting remarks of yes it could be too strong for and they don't specify this some watches. I've occasionally see on some wristwatches when they hairspring is jumping around wallets being demagnetized will have it looping part of it over the regulator pins in the F they go in fix that or just do it again that usually sometimes fixes itself. Then I don't know about the silicon hairsprings whether that is a possibility of damaging blows because I have a suspicion that silicon might be brittle even if it is a spring.

That of course there's the other little problem Omega's not dealing with really large watches like pocket watches.

Plus of course they have really deep pockets and they can recommend whatever they feel like because well I can. But I do like the idea of the solid-state detectors at these things have that tell you whether you have a magnetic field are not as I don't think the compass method is really reliable even though it's been around for very long time.

 

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