Magnetizer/Demagnetizer

[David King]

http://radialmagnet.com/store/pd-513...m?categoryId=9

These are pretty cheap...

[TGD]

my experience about magnetizers, I'll try to explain, sorry for my poor english, anyway.

I'm working around a new magnetizer close to the Gingery's project. If it's a little bigger, it works perfectly with both alnico and ceramic magnets (rods and bars).

Basically they are two electromagnets working in opposite phase, electronic to drive two bobbins is very easy to build (a rectifier, a normally open switch, a fuse and few other things); what is very hard to find is the soft iron used as core for the bobbins. It must be an irons with < 2% of carbonium parts in order to have higher magnetic permeability, and few industries in the world made this iron knows as ARMCO. Here in Italy only one factory has it, AKSteel of Genova, but they do industrial supplies only. In other hands, also surfing on the net, I never found this soft iron type.
The only way to have it and build a powerful magnetizer is to use a common iron 360 and decarbure it. It means to previously mill all iron parts and put them in a vacuum oven to 950° to permit to the iron to lose all carbonium athoms. Aftert this operations (about 24/28 hours) all parts must be milled again and refined. It's a long and expensive process to do; I' ve been lucky because I have a friend of mine working in that field and he did it for me for free in his loose time.
So, if someone wants a professional magnetizer, or have a friend like mine , or is much better to buy for less than 600 $ MasterMagnetics MAG24C.

My 2 cents.

Piero Terracina

[Electricdaveyboy]

I am working on a magnetizer at the moment and I found out that you woun´t get enough current trough the wire to change the magnetic field in a ceramic /ferrit or neo magnet wehn useing the gingery manetizer.

I am looking forward to get this done with two big caps attached to an aircoil.
But I am a bit scared because of the high current(K-Amperes !)that will flow for a few m-seconds.The other problem is to find a swich that will last for a while.

Cheers
david

[Joe Gwinn]

Basically they are two electromagnets working in opposite phase, electronic to drive two bobbins is very easy to build (a rectifier, a normally open switch, a fuse and few other things); what is very hard to find is the soft iron used as core for the bobbins. It must be an irons with < 2% of carbonium parts in order to have higher magnetic permeability, and few industries in the world made this iron knows as ARMCO. Here in Italy only one factory has it, AKSteel of Genova, but they do industrial supplies only. In other hands, also surfing on the net, I never found this soft iron type.

In English, this sounds like "electrical iron". By the way, the carbon must be less than 0.02%, not 2%. There was a long discussion of this material on this pickup makers forum, and here is the technical data: http://cartech.ides.com/datasheet.as...=TechArt&E=194

In the USA, ARMCO is the name of a company, not a steel. ARMCO is now known as AK Steel: http://www.fundinguniverse.com/compa...y-History.html

Which Gingery project (by title) are you building?

The only way to have it and build a powerful magnetizer is to use a common iron 360 and decarbure it. It means to previously mill all iron parts and put them in a vacuum oven to 950° [C] to permit to the iron to lose all carbonium atoms. After this operations (about 24/28 hours) all parts must be milled again and refined. It's a long and expensive process to do; I've been lucky because I have a friend of mine working in that field and he did it for me for free in his loose time.

This is called a "vacuum anneal" in English. The carbon atoms are not gone, but are not as much a problem than if the steel were hard.

The alloy "iron 360" may be an Italian form of mild steel. What is the analysis (percent by weight of the elements in the alloy) of iron 360?

So, if someone wants a professional magnetizer, or have a friend like mine , or is much better to buy for less than 600 $ MasterMagnetics MAG24C.

Actually, although electrical iron is best for such uses, it is not essential. One may use ordinary laminated transformer iron, which is in fact silicon steel. Or ordinary mild steel (alloy 1018), perhaps annealed. Or, ordinary hot-rolled steel.

[Joe Gwinn]

I am working on a magnetizer at the moment and I found out that you woun't get enough current trough the wire to change the magnetic field in a ceramic /ferrite or neo magnet when using the gingery magnetizer.

You should be able to charge all but rare earth magnets with a big electromagnet, while rare earth magnets require capacitor-discharge magnetizers.

I am looking forward to get this done with two big caps attached to an aircoil. But I am a bit scared because of the high current (K-Amperes !) that will flow for a few m-seconds.

The high current isn't much of a problem, as it only lasts for a short time, but the high voltage needed to drive the current requires some attention to detail.

Also, it's very bad for the capacitors if the voltage reverses, which will certainly happen if one does not arrange the coil-capacitor system to be somewhat overdamped (so the circuit cannot ring).

The other problem is to find a switch that will last for a while.

A large mercury relay intended for use in power circuits will work. These may be bought on ebay fairly cheaply.


Commercial capacitor-discharge units charge the capacitors to about 1,000 to 2,000 volts, and contain more than enough energy to kill in a single mishap.

http://www.magnet-physik.de/products...ng%20technique

If you do not already know how to arrange the coil-cap system to be overdamped means, and/or how to connect capacitors in series to achieve the needed voltages, I would defer this project for some self-education.

Also, the necessary capacitors are quite expensive, and one can easily exceed the $600 for the commercial magnetizer.

[TGD]

In English, this sounds like "electrical iron". By the way, the carbon must be less than 0.02%, not 2%. There was a long discussion of this material on this pickup makers forum, and here is the technical data: http://cartech.ides.com/datasheet.as...=TechArt&E=194

In the USA, ARMCO is the name of a company, not a steel. ARMCO is now known as AK Steel: http://www.fundinguniverse.com/compa...y-History.html

Which Gingery project (by title) are you building?

This is called a "vacuum anneal" in English. The carbon atoms are not gone, but are not as much a problem than if the steel were hard.

The alloy "iron 360" may be an Italian form of mild steel. What is the analysis (percent by weight of the elements in the alloy) of iron 360?

Actually, although electrical iron is best for such uses, it is not essential. One may use ordinary laminated transformer iron, which is in fact silicon steel. Or ordinary mild steel (alloy 1018), perhaps annealed. Or, ordinary hot-rolled steel.

Thank you for all there technical information, Joe. I'm a pickups maker not a magnetizer builder, so what I'm looking for is a professional magnetizer for my job ! All informations I found have been enough to build a good one, with many difficulties, anyway. Just today I received from my friend all milled pieces in pure iron 100%. I' ve now to wrap the bobbins and assebly the electric parts. I' ll be happy to post a picture when finished. Keep in touch.

Piero