demagnetizing alnico 5 rods

[John Carlsen]

Hey everyone. Just curious if there's an easy-ish way to demagnetize alnico 5 rod magnets to make them easier to work with in assembly. I have the misfortune of only have charged ones. Just wondering if there is a way to discharge them as much as possible. Really sucks to bevel them with a charge!

[copperheadroads]

You need 2 neo magnets & have opposing poles facing each other ,then pass you rods through the magnets

[big_teee]

I have 2 ceramic block magnets stuck side by side to my desk.
One is north up, the other south up.
I take the magets and run them across both magnets a couple of times.
I turn the maget around and repeat the process.
They may still have a little polarity left, but good enough to work with.
Good Luck,
Terry

[John Carlsen]

Hey guys, thanks a bunch for the pointers!! So, when you pass them through the opposing fields, I assume you need to run them through vertically, the same way as charging, correct? Thanks!

John

[copperheadroads]

Yes ,& like Terry said turn the magnet repeatedly

[SonnyW]

If you have a bunch to do, you might want to try one of these toolmakers plate demagnetizers. I bought mine used for about $30. I see them on ebay all the time. They do the job, I got mine for degaussing humbucker bars, which it does well, but I just did a little test, and charged up an Alnico 5 .187x688 rod to 1380 gauss then demagnetized it back to under 150. If I fool around with it I can get them down to under 100 which is not much charge at all. I'm measuring with an Alpha Labs gaussmeter. I just hold the rod vertically on the plate and press the switch for a couple of seconds then pull the rod away slowly before releasing the switch. It's handy and a nice complement to a magnetizer but probably not worth looking for unless you have a lot of them to do.

[Magnut]

If you push the pole toward a neo magnet you will feel it resist then it will begin to get sucked toward the neo. At that point stop, wait a second, then back off. Do this again to the opposite pole and on the opposite side of the neo. It will be pretty much demagnetized. It takes a little practice but it gets easier. Go slow and don't let the pole touch the magnet.

[John Carlsen]

Thanks for the replies guys. I saw some of those plate demagnetizers, so it's good to know that they work pretty well.

[Possum]

The demagnetizer works better if you use a Variac on it. I used to use mine that way alot, now days I just use a ceramic bar magnet and push opposing poles to the alnico to knock it down. You have to be careful though because it will regain much of the stength you think you knocked down. So I'll recharge with just the ceramic bar poles attracting, and eventually get it to where I want it and so its stable and stays there....

[David King]

Possum, a sight for sore eyes I tell you. The nice weather must have brought you out?
So you push the same pole of two ceramics at both ends of the alnico simultaneously?

[hrbay]

We use to demag aircraft wheel bolts after checking for cracks with an ac yoke, believe it was just a large ac coil with a trigger. The technique involved moving the yoke slowly away from the part until the gauss reading was lowered . Large solder gun can probably couple to ferrous parts and might be used for this too if I'm not mistooken.

[Possum]

No, I do each side seperately, I don't put out alot of product, so its kinda stupid slow way but I am so used to doing it that way, its real fast. You just have to watch for the alnico regaining its charge. I only used the demagnetizer and variac on fully assembled strat pickups, you can get it pretty dialed in to hit exactly what you want in one pass over the top........
YEAH MAN, finally some SUN!!!! Just dug the recumbent bike out of the garage and dusted off the cobwebs, first short ride today to see if I have a heart attack or not, LOL...