Building A Simple Degausser

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This topic contains 8 replies, has 3 voices, and was last updated by  Kyuuketsuki 2 months, 3 weeks ago.

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  • Kyuuketsuki
    Participant
    #167661

    Hi Guys,

    Long time, no posts … I’m retired now so I concentrate more on writing (and DIY) than IT :)

    I have some hard drives I want to get rid of (old SCSI ones, no idea what’s on them) and, whilst I am aware I could simply hit them many times with a hammer or throw them in a fire, I’d prefer to demagnetise them. I also run a small home computer support business so it occurs to me that if I did have such a facility I could assure customers that any old drives they give me (for example, when upgrading) will be completely wiped.

    Now, a degausser (as I understand it) is just a magnetic field generator, is that right?

    It occurs to me that if I were to get hold of, say, a 15cm plastic pipe, neatly wrap a lot of wire around it and attach it to the mains in such a fashion that current flows in a loop (live to neutral), that would generate a magnetic field. The question then becomes firstly, would such a field be strong enough to destroy the data on a hard disc placed inside said pipe (UK current is 240V, 13A, alternating)?

    Another question … would a degausser destroy data on an old style DLT or Ultrium tapes?

    Thx :)

    James


    biggles77
    Spectator
    #214450

    Here you go James. A dandy, inexpensive device just built for your needs. :mrgreen: Hard Drive Degausser

    I was Googling last night for a DIY one and somebody had made on from the degausser unit from an old TV or CRT monitor. Seemed a tad risky if you put your fingers in the wrong place. Not sure if you want to risk having something like that laying around. The Home Made Unit. Alternative suggestion that I read were introducing it to Mr Sledgehammer,

    Recall reading an article in a tech magazine 15 to 20 years ago where an American serviceman serving in the Philippines had arranged with his girlfriend’s brothers to have his Filipino wife murdered so he could enjoy wedded bliss with LBFM number 2. He was a contentious chap, wrote the plan on a Word document and saved it all to a 5¼” Floppy Disc. When the MPs came round to question him after the death of his wife, to the bewilderment of the MPs, he ran into his office and locked the door. It was shortly discovered that he had used a pair of scissors that cut in a zig-zag pattern to cut up the floppies and so render his guilty evidence unreadable. The investigating guy really wanted to retrieve the evidence so he approach data recovery experts in his quest. He found one that suited his needs and asked them if they could recover the data and what would it cost. Now remember how long ago this was, circa 2000, and they replied US$100,000. Back then that was a lot of money (which it still is today, especially to poor people like me) and there was no way he would be authorised that amount but he was a tenacious bugger so he tried other avenues so he could get his man.

    Now the pieces were cut into zig-zags so he he got a piece of cardboard, a new 5¼” floppy disc and some sticky tape. He ended up taping the pieces all back together and inserted the reconstructed floppy into the sleeve of the new disc, put the disc into a FDD and with a massive outlay of something like US$5 to $10 was able to recover the Word document with the evil plans and Mr Serviceman was found guilty of murder and I guess it was off to Leavenworth for an all expenses paid vacation.

    Yeah, a bit :offtopic: but an interesting story I thought. That could not happen to a HDD due to the lack of spacing between the drive heads and the platters. The thickness of the sticky tape would have resulted in the heads getting mangled on the first rotation. A HDD is a lot more delicate so a physical way to stop data recovery and destroy the device would be to bash the shit out of it, drill holes all over the platters, remove the platters and apply a sandpaper “shine” to the surface and a plethora of other physical options.

    There is also the software version. I have a program called HardDriveEraser. It was an excellent tool, simple to use and there was no installing as it ran in portable mode. Only problem with it was to wipe to the DOD standards required 3 passes and I remember in 2011 that I did 1 pass on a 40GB laptop HDD and it took 75 minutes. The author’s overwrite setting to be sure to be sure it was beyond recovery was to use the 35 pass option (which was about 43 hours for just 1 drive). Considering the size of drives now, this software option (with this actual utility) really isn’t feasible. There may be other apps that can do it quicker but the manual way now seems the best to me now. I open them up, remove the magnets to give to friends so they can polarise their screwdrivers etc and not drop any small screws they are applying torsional forces to. All that is needed is a torx driver to remove bits and a hammer to mess up the platters and heads. Good times!

    With the Home Made Degausser, I have no idea how well it works due to me not knowing how much magnetisimy stuff is required to disrupt the tracks beyond recovery.

    Please let us know what you do and how well you think it works. I would be interested. [ATTACH=JSON]{“data-align”:”none”,”data-size”:”small”,”data-attachmentid”:517910}[/ATTACH]


    Kyuuketsuki
    Participant
    #312546

    Hi Biggles,

    biggles77;n517909 wrote:
    Please let us know what you do and how well you think it works. I would be interested.

    I will … thanks for the link and yes, I agree the story was interesting, if it’s OK I’ll forward that to a few of my IT friends :)

    James


    biggles77
    Spectator
    #214451

    James, anything published her is for public consumption so go for your life. Share the mirth around. :mrgreen:


    Kyuuketsuki
    Participant
    #312548
    biggles77;n517916 wrote:
    James, anything published her is for public consumption so go for your life. Share the mirth around. :mrgreen:

    Thanks.

    On the subject of mirth, I just went to your first link (I’d already checked out the home made unit) and nearly had a heart attack!

    Again, thanks :)

    James


    Ossian
    Moderator
    #192079
    Kyuuketsuki;n517919 wrote:
    Thanks.

    On the subject of mirth, I just went to your first link (I’d already checked out the home made unit) and nearly had a heart attack!

    Again, thanks :)

    James

    The clue is “NSA and DOD approved” Each TLA immediately adds at least one order of magnitude to the price and given it needs two (probably radically different) sets of approvals, I can see a couple of extra zeros for that.

    (I THINK I am joking with the above, but probably am far too close to the truth for comfort :twisted:)


    Kyuuketsuki
    Participant
    #312549

    So Guys,

    Is this, on Amazon, something that might do the same trick?

    https://www.amazon.co.uk/gp/product/B01F0TFDHK/ref=ask_ql_qh_dp_hza

    One customer response assures me that it will.

    James


    biggles77
    Spectator
    #214452

    That’s a degausser for an old TV or CRT screen. Don’t imagine it’s going to have the grunt to serious bugger up the platter on a HDD. James, are you wanting to wipe the HDDs so they can be used again or are you just wanting to make it so the data is unrecoverable? As mentioned above, physical destruction may be a much cheaper and more reliable option if you just want to make the data unrecoverable. Big difference between the Amazon device and the joke one I included in my first post. I think it would likely make a mess of a floppy disk thought and a tape. Dropping a large magnet on a floppy or tape and leaving it there overnight would possibly do that as well.


    Kyuuketsuki
    Participant
    #312550

    Hi Biggles,

    biggles77;n517937 wrote:
    That’s a degausser for an old TV or CRT screen. Don’t imagine it’s going to have the grunt to serious bugger up the platter on a HDD.

    OK :)

    biggles77;n517937 wrote:
    James, are you wanting to wipe the HDDs so they can be used again or are you just wanting to make it so the data is unrecoverable? As mentioned above, physical destruction may be a much cheaper and more reliable option if you just want to make the data unrecoverable. Big difference between the Amazon device and the joke one I included in my first post. I think it would likely make a mess of a floppy disk thought and a tape. Dropping a large magnet on a floppy or tape and leaving it there overnight would possibly do that as well.

    Ultimately I simply want to ensure data destruction and was prepared to try building my own unaware that something might be available cheap enough to work. The customer response I got when I asked, assured me it would but I thought I’d try asking you guys first. In some ways, as long as the data is thoroughly destroyed (cannot be recovered), it works better for me to not physically destroy the disk drive, disk drives are useful :)

    I’m wondering whether I should buy it anyway and see what it is capable of, £15 is not that high a price and I can get that back against my tax in a year or so’s time :)

    James

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