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FYI how to degauss a hard disk cheap (bulk erase)

  • Hard Drives
  • Storage
Last response: in Storage
September 29, 2006 2:44:24 PM

I had some drives that were defective and needed to be RMA'ed. I was concerned about sending back a bad drive with critical corporate data that may still be recoverable. Since I could not wipe the drive with software because the OS would not recognize the drive, I looked into buying a degaussing bulk eraser but found out they cost about ten times the cost of a new drive.

I got the idea of using a permanent magnet to erase the drive but I read many postings of people who tried but failed using old speaker magnets. I then found a site called K&J Magnetics ( which sells super strong neodymium rare earth magnets.

I did some experiments on an extra working drive. The neodymium magnets fully erased a hard drive with less then 30 sec of rubbing in circles on both sides of the drives. They also worked great to erase 3-1/2" floppy disks and some flash memory cards.

Just be carefully to read and heed the warnings about the magnets on K&J's site. The magnets are much stronger than you could imagine. Getting your finger caught between two magnets will cause a serious pinch. Also they are incredible hard to get apart once they stuck together.

More about : fyi degauss hard disk cheap bulk erase

September 29, 2006 3:00:14 PM

Nice tip, although I wouldn't suggest doing this to a drive that will remain in use. Even a slight bend on the read/write heads or a misalignment of the spinning mechanism can put the tip of the heads straight onto the platter, and at 5000+ RPMs, you get the picture. Just don't do it on a good drive unless you can afford to make the gamble.
a b G Storage
September 29, 2006 3:10:27 PM

Wd has a utility that writes 1's or 0's to the drive.

But it only works on WD.
Related resources
September 29, 2006 3:16:13 PM

Running a magnet (even a super strong one) over the drive is no guarrantee that the data is unrecoverable. You have no way of knowing if the data was wiped or just a few bits of the allocation table got corrupted. Professional data recovery can sometimes get data from a drive that has been written over several times.

If it is "critical corporate data" as you say, you just eat the cost and throw the bad drive in the incinerator. Why risk $millions in lawsuits, intellectual property loss, and bad press for stupidity over a $200 hard drive.
September 30, 2006 1:36:59 AM

Still a good tip, if anyone is looking for some good rare earth magnats, take apart some old drive, scsi works bes, this are very powerful.
September 30, 2006 2:43:12 AM

take the drive apart and leave a magnet in it over night.. i guess RMAing it would be rather difficult after that..
October 1, 2006 5:10:17 AM

When I discard a drive, I open it up and bend or hammer the platters!

October 1, 2006 2:36:12 PM

Discarding and RAM'ing a drive are apples an oranges when you think about what is involved in the support contract. Dell would not be happy if they got back a hdd that look like it came off airplane wreck. It defeats the point to getting a 'free' replacement. Our best practice these days is to only use bonded couriers to return the drives, data gets out, law is on our side.
October 1, 2006 2:45:27 PM

Did you attempt file recovery with a program like Get Data Back after taking a magnet to the hard drive?

Once you corrupt a drives partition table the drive will appear empty, but it still may contain many files recoverable by software.
October 1, 2006 3:06:16 PM

1. This isn't enough: at least 50% of the data can still be recovered when erased with a permanent magnet, it doesn't matter how strong it is.
2. Magnetic fields have absolutely nothing to do with Flash memories: your memory was already damaged or files already corrupted.
a b G Storage
October 28, 2010 9:24:10 PM

Damn. A 4 year old necro. PLEASE look at OP date before posting
October 28, 2010 9:25:37 PM

This topic has been closed by Mousemonkey