Lions, tigers, and large neodymium magnets, oh my!

[Tonestack]

I ordered four 3" long 1/2" x 1/2" neodymium magnets, so that I could demagnetize a bunch of ALNICO rod magnets that I purchased years ago. I have handled neodymium magnets before, but nothing this large. These magnets are unbelievably powerful. It takes an amazing amount of force to pull them apart, even with spacers installed.

With that said, what is the best way to use these things to demagnetize ALNICO rods? I fear that I may never get them apart if I remove the spacers.

[big_teee]

I ordered four 3" long 1/2" x 1/2" neodymium magnets, so that I could demagnetize a bunch of ALNICO rod magnets that I purchased years ago. I have handled neodymium magnets before, but nothing this large. These magnets are unbelievably powerful. It takes an amazing amount of force to pull them apart, even with spacers installed.

With that said, what is the best way to use these things to demagnetize ALNICO rods? I fear that I may never get them apart if I remove the spacers.

As in Demagnetize Fender type rod magnets?
I do that with Ceramic magnets.
I have 2 Ceramic block magnets stuck on my desk side by side.
One is north up and the other is south up.
I run the Alnico magnet or pickup over the blocks a couple of times.
It makes them nearly flat, and easier to work with.
If you use the large NEOs you won't demagnetize them, you will just reverse the polarity.
When you take them off the NEOs they will be recharged in the opposite direction.
T

**Edit
I guess if you attach the NEOs to a vise and keep some separation between the Alnico Rods, and the NEOs?
Maybe that would degauss, without reversing the Polarity!

[FunkyKikuchiyo]

Be careful with those - a good crash with those and they'll shatter nicely. And by nicely I mean I hope your face is shielded.

I'd get them into some sort of harness/setup to avoid those accidents. I have a couple 1/2" cubes that are a pain to get apart, so I can only imagine how those are.

Are you trying to magnetize or demagnetize, or both? The vise set up is pretty standard.

[David Schwab]

With that said, what is the best way to use these things to demagnetize ALNICO rods? I fear that I may never get them apart if I remove the spacers.

Put them in a drill press vice:

[big_teee]

Will that demagnetize, or remagnetize?
T

[Tonestack]

I attempted to install two of the 3" x 1/2" x 1/2" magnets on each jaw of my Parrot vise. The results were disastrous. I have blood blisters on both of my hands, and two of the magnets shattered. luckily, I was wearing eye protection. A 3" x 1/2" x 1/2" neodymium magnet definitely has over 65lbs of pull force.

[David Schwab]

Will that demagnetize, or remagnetize?
T

Both. I'm magnetizing the Jazz bobbin in this photo, but if you flip it over it will demagnetize them, and you can also flip the polarity.

You can adjust the jaw opening and use spacers if you want to weaken the magnets, etc.

[David Schwab]

I attempted to install two of the 3" x 1/2" x 1/2" magnets on each jaw of my Parrot vise. The results were disastrous. I have blood blisters on both of my hands, and two of the magnets shattered. luckily, I was wearing eye protection. A 3" x 1/2" x 1/2" neodymium magnet definitely has over 65lbs of pull force.

They might be too large. But even the four I'm using here are very hard to pull apart. If you stick one at a time on the vice, and keep the jaws far enough apart, they should not jump off. I can get them pretty close together and they stay put. Make sure it's an iron or steel vice so they stick. You can clamp some wood in-between when you are not using it. If necessary, epoxy them on one at a time.

[Tonestack]

What are the dimensions of your magnets? I need to find a more manageable neodymium magnet size. A stacked pair of 3" x 1/2" x 1/2" neodymium magnets is incredibly difficult to pry loose from the jaw of a vise.

[FunkyKikuchiyo]

Check out kjmagnetics.com - They make some that have mounting holes in them. There might be something there that'll work for you.

[David Schwab]

What are the dimensions of your magnets? I need to find a more manageable neodymium magnet size. A stacked pair of 3" x 1/2" x 1/2" neodymium magnets is incredibly difficult to pry loose from the jaw of a vise.

1 1/2" x 1/4" x 1/4"

K&J Magnetics - Products

What I'm not understanding is if they are so hard to pry loose from the vice, how did they end up shattering?

[David King]

To really demagnetize you'll need a demagnetizer, one that sends out a diminishing series of AC pulses (waves). doing it with neos results in some oddball momentary results such as two south poles.
I'll knock them down to 0 only to come back later to find they still have a charge again. Easier said than done.

[minime]

David, What is the purpose of the metallic looking strip connecting the magnets in the photograph?

[David Schwab]

To really demagnetize you'll need a demagnetizer, one that sends out a diminishing series of AC pulses (waves). doing it with neos results in some oddball momentary results such as two south poles.
I'll knock them down to 0 only to come back later to find they still have a charge again. Easier said than done.

True, but when do you ever need them to have no charge for any extended period of time? They serve no purpose that way. I think the most anyone would need is to charge, recharge or flip polarity on a pickup magnet.

I use that jog to charge alnicos, and to re-polarize them every now and then.

[David Schwab]

David, What is the purpose of the metallic looking strip connecting the magnets in the photograph?

It's a piece of copper shielding tape. I was sticking it to the magnets to see if I could get electrical continuity to them for grounding purposes.