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Demagnetizer Recommendations

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    yes,  "the old school" one is best.  but you need to learn how to use it.  it has many other uses,  like magnatizing a screw driver.  and then de magnatizing it.  vin

I actually have one of these and needed to rewire the plugs.


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4 hours ago, omx5o said:

If the field appears to be too strong, why not simply start it with the movement farther away? Say a few inches or something like that.

Good idea, and I've tried that, but my compass still behaves exactly the same before and after. I've also tried with screw drivers but they pick up screws just as well as before "demagnitizing". Maybe there's something wrong with my unit, or I just haven't got "the touch" when used with 240V!?

Anyone with any experience of the Elma Antimag?

I'm thinking that I'd be willing to invest in an Elma Antimag. It would certainly eliminate the need for the "right touch", but would it eliminate magnetism, or are these demagnetizers simply snake oil? Sorry for being skeptical, but my experiences so far haven't exactly been brilliant.

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31 minutes ago, VWatchie said:

I'm thinking that I'd be willing to invest in an Elma Antimag. It would certainly eliminate the need for the "right touch", but would it eliminate magnetism, or are these demagnetizers simply snake oil? Sorry for being skeptical, but my experiences so far haven't exactly been brilliant.

The  Elma Antimag works really well we have one at the shop I work at it works really nice. Then at home I have a different brand same principle I've used it for years. Easy to use just put whatever you have on push the button and I usually move the watch around a couple of times and that's because I'm not entirely sure where the field is how far out it goes so moving around the couplet times seems to work fine.

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7 hours ago, omx5o said:

If the field appears to be too strong, why not simply start it with the movement farther away? Say a few inches or something like that.

It’s tricky. If I remember correctly, magnetism intensity follows a cube rule with respect to distance, so it suddenly drops off as you move away. So you’d hardly want to distance it at all. 

The problem with this thing is that the field is so strong that you literally struggle to pull watches or tweezers off the thing. 

I think the better option for 240V would either be a resistor to halve the intensity, or better than that, a rheostat to ramp down the intensity. 

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I’ll possibly go for the Elma when the time comes to purchase one.
It’s 240V with 3 pin UK plug on the site I’m looking at – it’s manufactured for demagnetising watches and I’d imagine it will do it well. I won’t be questioning whether I moved away from the demagnetiser too slow or too quick etc.

I might consider one of the cheaper ones, probably Etic, depending on finances as they seem to be vanishing quickly buying all the tools I need.

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a standard  watch or tool mag./de mag.  is a simple wire wound coil attached to 110 volts/no ground, alternating curent.  in fact you can make one.  only using one requires some experience as listed in de Carles' book.  vin

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On ‎2018‎-‎05‎-‎07 at 11:08 PM, JohnR725 said:

The  Elma Antimag works really well we have one at the shop I work at it works really nice. Then at home I have a different brand same principle I've used it for years. Easy to use just put whatever you have on push the button and I usually move the watch around a couple of times and that's because I'm not entirely sure where the field is how far out it goes so moving around the couplet times seems to work fine.

Thanks for your reply, and although I was still sceptical I made up my mind to get myself an Elma. I'm glad I did as the Elma Antimag machine works very well indeed!

In my case, the Chinese demagnetizer was a complete waste of money, at least as I have only access to 240 Volts. It just doesn't work for me.

I've recorded a video review in three short parts (before, during, and after demagnetizing) as I have no video editing experience, and for anyone interested you can watch them by clicking on the following links:

Elma Antimag Demagnetizer Review Part 1 of 3.
Elma Antimag Demagnetizer Review Part 2 of 3.
Elma Antimag Demagnetizer Review Part 3 of 3.

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On 1/12/2017 at 11:26 AM, oldhippy said:

These little blighters are fine. I've said many times on here demagnetize the movement should be the first thing before you undertake the repair it will save you time.  

I have one too. I sometimes use a 6mm spacer if I want to reduce the field strength on what I consider to be a "delicate" watch upon switch on. Mine has a transformer using just the E`s,  The I`s  were never fitted for this application. As you move the watch away do so slowly. The magnetic field reduces by inverse square law with distance. 

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I have one too. I sometimes use a 6mm spacer if I want to reduce the field strength on what I consider to be a "delicate" watch upon switch on. Mine has a transformer using just the E`s,  The I`s  were never fitted for this application. As you move the watch away do so slowly. The magnetic field reduces by inverse square law with distance. 

That is Deep Math OH


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I had pretty good success with a vintage KD demagnetizer. It was pretty affordable at ~$20 + ~15 shipping. It's oval shaped and it wraps around the entire  watch or screwdriver. Much better than my DIY solution.

Previously, I made a demagnetizer by taking an old transform and removing one side of the metal plates. That way the magnetic flux flows through the air and thus your parts. It's not very good since the gap between the transformer and your part exponentially decreases the strength. I could magnetizer and demagnetize objects just fine but it doesn't feel as strong as the KD one.

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If you like to build electronics - build your own - it's simple!

Basically it is a coil that you connect a capacitor to, in parallel.  The created magnetic field  is "automatically"  decreased as the capacitor discharges. 

Here is a picture of a simpel version I made using 2x12V PCB transformers (to get mains insulation) and a modified audiotransformer.

 

 

 

 

Demag1.jpg

Demag2.jpg

Demag3.jpg

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@RCDesign: Am I actually doing it right ?? :unsure:

The presents of a big capacitor in your design has made me think whether my shaded pole motor is actually such a good tool to demagnetize a watch?

m-22.jpg.93f5e1eaaf537fb3da58c1a5d23e97c4.jpg.94c95c3575bb131f78597e774d9e7bda.jpg

As you know, a shaded pole motor has a coil which is energized by 240V Alternating Current (AC). This causes the magnetic flux in the coil / stator to alternate, the North- and South-pole swap places 50 times a second (50Hz in the EU, 60 Hz in US).

I normally energize the coil and slowly insert the watch-part into the stator (where the rotor used to be), keep it there for about 10 seconds and then pull it slowly out. Once about 20cm out I release the power-button. By doing this I assumed that the magnetic particles in the watch-part are "fully" disoriented, i.e. lost there combined direction of magnetism = demagnetized.

If your design works with a capacitor than I assume there some kind of DC involved? As a minimum (I assume) during the capacitor discharge state. Depending on the speed at which this discharge happens, again I assume, the magnetic flux is in one direction? If the discharge takes long, that would magnetize the watch again.

I'm a bit confused about how your system works and like to compare it with the workings of a shaded pole motor ..... so, could you please elaborate on how your system works? Perhaps include a schematic of the setup and components?

Hope to hear ...... :)

 

Edited by Endeavor

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For anyone that's not sure how there supposed to be using the coil type demagnetizer this is what Omega recommends. Then even though it's in the picture I'm going to quote some text "Demagnetisation according to the three axes x, y and z is necessary when using this type of instrument. Do not release the instrument when the object is inside the tunnel as it could finish up being more magnetised than before." Then you will notice in the fine print a minimum of 50 cm away from the coil before you take your finger off the button and five seconds to get to the 50 cm. 

Demagnetisation procedure.JPG

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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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