# hard-drive destruction: how much to assure unreadability? **URL:** \ **Category:** Factual Questions\ **Created:** [August 28, 2012, 4:24pm UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942 "2012-08-28T16:24:14Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [August 28, 2012, 9:31pm UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/21 "2012-08-28T21:31:02Z")
I’m in charge of shooting ours from my employer. A .22 caliber will often not penetrate all the way through. A 30-06 makes a devastating hole. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 28, 2012, 10:19pm UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/22 "2012-08-28T22:19:09Z")
> [@Machine\_Elf](#): > > Some clarification is in order; sorry for not being more upfront. > > This is a job for work, and rather than one drive, it’s approximately 150 of them, so the process needs to be fairly quick and efficient. I don’t know what data is/was on them; it’s entirely possible some of them are from HR and contain personal identifying info for some/all of our employees (e.g. SSN’s, bank account info for payroll deposits, etc.). Some other drives may contain proprietary/confidential info. > > I’m pretty sure folding them in a hydraulic press will result in an extremely low probability of data recovery. Mostly I was curious to know just how badly a drive has been mangled and still actually been able to have data retrieved from it. Hire somebody’s teenager, hand him a hammer, and put him to work for eight hours. ---
**Author:** ![jdc](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@jdc](https://boards.straightdope.com/u/jdc)\ **Post date:** [August 28, 2012, 11:34pm UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/23 "2012-08-28T23:34:42Z")
There are companies that will physically shred HD’s and will give you a certificate of destruction. If you have 150 HD’s to get rid of, that is the way to go. ---
**Author:** ![darrakk](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@darrakk](https://boards.straightdope.com/u/darrakk)\ **Post date:** [August 29, 2012, 2:56am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/24 "2012-08-29T02:56:01Z")
> [@beowulff](#): > > Oh, and **darrakk** - a big electromagnet is probably not sufficient. Mechanical damage is the way to go. If you are removing your porn collection from the laptop you are about to hand over to your mom, an electromagnet is fine. If you are on the run from the CIA, I still say thermite. ---
**Author:** ![darrakk](https://avatars.discourse-cdn.com/v4/letter/d/838e76/32.png) [@darrakk](https://boards.straightdope.com/u/darrakk)\ **Post date:** [August 29, 2012, 2:59am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/25 "2012-08-29T02:59:09Z")
> [@jdc](#): > > There are companies that will physically shred HD’s and will give you a certificate of destruction. If you have 150 HD’s to get rid of, that is the way to go. Agree with this. ---
**Author:** ![Xema](https://avatars.discourse-cdn.com/v4/letter/x/9de053/32.png) [@Xema](https://boards.straightdope.com/u/Xema)\ **Post date:** [August 29, 2012, 3:31am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/26 "2012-08-29T03:31:54Z")
> [@jdc](#): > > There are companies that will physically shred HD’s and will give you a certificate of destruction. What is the use of such a certificate? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [August 29, 2012, 3:37am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/27 "2012-08-29T03:37:59Z")
> [@Xema](#): > > What is the use of such a certificate? I’d assume they were insured and you’d have a cause of action against them if they didn’t destroy the drive. Trouble is, if the FBI wants you for something they could be waiting there with a warrant. Best to destroy them yourself if there’s incriminating evidence on them, except for it being wrong and illegal, so never do that :rolleyes: ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [August 29, 2012, 3:43am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/28 "2012-08-29T03:43:32Z")
> [@darrakk](#): > > If you are removing your porn collection from the laptop you are about to hand over to your mom, an electromagnet is fine. If you are on the run from the CIA, I still say thermite. 99.9999% of the people in the world don’t have access to an electromagnet strong enough. 100% of the people in the world have access to a rock. ---
**Author:** ![Dr.Colossus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.colossus/32/9423_2.png) [@Dr.Colossus](https://boards.straightdope.com/u/Dr.Colossus)\ **Post date:** [August 29, 2012, 4:02am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/29 "2012-08-29T04:02:30Z")
after the season opener of Breaking Bad, i took a small interest in the viability of magnetically de-gaussing a hard drive beyond recovery. i know a lot of people here claim it’s not the answer, but it’s how the NSA destroys classified data on hard drives \*(because it works to a practical degree). there is also a degaussing magnet device called the [Guard Dog](http://www.technologyreview.com/news/405951/how-to-kill-a-hard-drive/) being produced for absolute-top-secret, on the fly HD destruction–prompted by the concept of a classified aircraft going down behind enemy lines and the survivors not having time to grind their hardrives into dust before being taken prisoner (apparently grinding them into dust is the most certain method of destroying all data). i also read someplace that you can use programs to wipe the data, overwrite new data, wipe that, and repeat a few time and that is effective. i think there’s a level of practically that will make this all debatable; NSA/CIA level data eradication isn’t really easy for consumer-level products short of physically un-existing the drive, but i as well don’t know that it is often necessary. ---
**Author:** ![Dr.Colossus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.colossus/32/9423_2.png) [@Dr.Colossus](https://boards.straightdope.com/u/Dr.Colossus)\ **Post date:** [August 29, 2012, 4:07am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/30 "2012-08-29T04:07:17Z")
> [@beowulff](#): > > 99.9999% of the people in the world don’t have access to an electromagnet strong enough. 100% of the people in the world have access to a rock. what about all the degaussers available on the consumer market? they work reasonably well enough as a rock, i’d think. as has been stated, anyone who goes to the work of recovering data from a professionally degaussed hard drive could get bits and pieces off a rock-smashed drive as well. again, i think it’s all going to be debatable due to the sensitivity of the info and the potential of someone getting a hold of it who has the wherewithal to recover the data. all i’m saying is they market devices to do this…it’s not “they are watching you from satellites” level-paranoia-destruction, but it’s sufficient for nearly all consumer applications. ---
**Author:** ![astro](https://avatars.discourse-cdn.com/v4/letter/a/9dc877/32.png) [@astro](https://boards.straightdope.com/u/astro)\ **Post date:** [August 29, 2012, 4:18am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/31 "2012-08-29T04:18:00Z")
> [@Michael63129](#): > > For those saying that magnets don’t work, there’s plenty of videos on YouTube of people killing hard drives with magnets; ironically, including magnets from hard drives (see [this example](http://www.youtube.com/watch?v=iK1RR7Bhd-s), starting at 7:30; note also that this drive has no R/W head on the top platter, so it didn’t happen from being accidentally touched by the magnet). I have tried this myself, with a microwave magnetron magnet and the drive (not opened up) immediately began the “click of death” (this was an older drive, a few GB from an otherwise working computer somebody threw out). Note, the hard drive was running when I did this; a non-functioning drive wasn’t affected at all just by putting a magnet on it (to magnetize something, you stroke the magnet across it in one direction, which occurs with the platters spinning but not still). Notebook drives, especially modern ones with high data densities and very high coercivity, are going to be a lot harder to kill than desktop drives both in terms of the strength of the magnetic fields required to erase the data and overall physical toughness. Plus degaussers come in a variety of strengths. A hand held degausser suitable for erasing magnetic tape might easily be shrugged off by a notebook drive. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [August 29, 2012, 4:41am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/32 "2012-08-29T04:41:37Z")
> [@Dr.Colossus](#): > > what about all the degaussers available on the consumer market? they work reasonably well enough as a rock, i’d think. as has been stated, anyone who goes to the work of recovering data from a professionally degaussed hard drive could get bits and pieces off a rock-smashed drive as well. > > again, i think it’s all going to be debatable due to the sensitivity of the info and the potential of someone getting a hold of it who has the wherewithal to recover the data. > > all i’m saying is they market devices to do this…it’s not “they are watching you from satellites” level-paranoia-destruction, but it’s sufficient for nearly all consumer applications. Sorry, but physically damaging the platters is a much safer (and far, far cheaper) way of making a hard drive unreadable. Do you understand how a hard drive works? The read heads fly only [nanometers](http://en.wikipedia.org/wiki/Flying_height) above the platter’s surface. If you warp the platters, no data recover service is going to risk their read heads trying to read the drive. Now, the CIA/NSA may have robotically controlled read heads that might allow them to extract data, but they are also going to be able to recover residual data from a drive that’s been incompletely erased by an electromagnet. ---
**Author:** ![Dr.Colossus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.colossus/32/9423_2.png) [@Dr.Colossus](https://boards.straightdope.com/u/Dr.Colossus)\ **Post date:** [August 29, 2012, 4:57am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/33 "2012-08-29T04:57:50Z")
> [@beowulff](#): > > Sorry, but physically damaging the platters is a much safer (and far, far cheaper) way of making a hard drive unreadable. Do you understand how a hard drive works? The read heads fly only [nanometers](http://en.wikipedia.org/wiki/Flying_height) above the platter’s surface. If you warp the platters, no data recover service is going to risk their read heads trying to read the drive. Now, the CIA/NSA may have robotically controlled read heads that might allow them to extract data, but they are also going to be able to recover residual data from a drive that’s been incompletely erased by an electromagnet. i understand– but the op was asking in regard to quickly, reasonably-effectively erasing multiple hard drive efficiently, as part of his work duty. while i agree that a hypothetical thinking exercise on the most complete way to destroy _a_ hard-drive is open to lots of ideas (smashing with rocks being a totally viable entry). but–wouldn’t it be more practical for someone in his situation to obtain a commercially available professional degausser? again, i agree destroying them physically (by rocks, steamrollers, tossed into volcanoes, etc) will work, i just don’t know if he has the time to smash however many he has to deal with with rocks. plus his co-workers might think he’s acting a little too cave man. … wait– both the steamroller and volcano ideas allow you to deal with them in bulk, all at once. so i dunno, maybe those…? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [August 29, 2012, 5:01am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/34 "2012-08-29T05:01:39Z")
> [@Dr.Colossus](#): > > i understand– > but the op was asking in regard to quickly, reasonably-effectively erasing multiple hard drive efficiently, as part of his work duty. while i agree that a hypothetical thinking exercise on the most complete way to destroy _a_ hard-drive is open to lots of ideas (smashing with rocks being a totally viable entry). but–wouldn’t it be more practical for someone in his situation to obtain a commercially available professional degausser? > > again, i agree destroying them physically (by rocks, steamrollers, tossed into volcanoes, etc) will work, i just don’t know if he has the time to smash however many he has to deal with with rocks. > plus his co-workers might think he’s acting a little too cave man. > > … > wait– > both the steamroller and volcano ideas allow you to deal with them in bulk, all at once. so i dunno, maybe those…? Actually, the OP only said he had to destroy ONE drive… ---
**Author:** ![littlespeedysuperbike](https://avatars.discourse-cdn.com/v4/letter/l/53a042/32.png) [@littlespeedysuperbike](https://boards.straightdope.com/u/littlespeedysuperbike)\ **Post date:** [August 29, 2012, 5:07am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/35 "2012-08-29T05:07:04Z")
Rent an oxyacetylene torch setup (about $50 for the day) and use a heavy oxidizing flame to burn right through them. I bet you could get it done in a fat hour. Same process would work with an electric plasma cutter. ---
**Author:** ![Dr.Colossus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.colossus/32/9423_2.png) [@Dr.Colossus](https://boards.straightdope.com/u/Dr.Colossus)\ **Post date:** [August 29, 2012, 5:18am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/36 "2012-08-29T05:18:26Z")
> [@beowulff](#): > > Actually, the OP only said he had to destroy ONE drive… > [@Machine\_Elf](#): > > Some clarification is in order; sorry for not being more upfront. > > This is a job for work, and rather than one drive, it’s approximately 150 of them, so the process needs to be fairly quick and efficient. ?? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [August 29, 2012, 5:23am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/37 "2012-08-29T05:23:42Z")
Oh, you mean post #12… ---
**Author:** ![drachillix](https://avatars.discourse-cdn.com/v4/letter/d/48db29/32.png) [@drachillix](https://boards.straightdope.com/u/drachillix)\ **Post date:** [August 29, 2012, 6:00am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/38 "2012-08-29T06:00:39Z")
> [@Dr.Colossus](#): > > what about all the degaussers available on the consumer market? they work reasonably well enough as a rock, i’d think. as has been stated, anyone who goes to the work of recovering data from a professionally degaussed hard drive could get bits and pieces off a rock-smashed drive as well. > > again, i think it’s all going to be debatable due to the sensitivity of the info and the potential of someone getting a hold of it who has the wherewithal to recover the data. > > all i’m saying is they market devices to do this…it’s not “they are watching you from satellites” level-paranoia-destruction, but it’s sufficient for nearly all consumer applications. I would never bet on magnetic erasure unless it is with a device specifically designed for hard drives The magnets inside a hard drive are quite strong and hard drives are quite resilient against data damage from magnetic feilds. multi overwrite stuff like dban is more than sufficent for anything short of “Enemy of the state” scenarios. serious platter damage will pretty much make the drive unreadable to anything. Just drilling through the media surface will create enough of a burr around the hole that at 7200 rpm, the heads hitting it would be like ramming a dragster into a 10’ thick concrete wall at 200+mph. In addition you will have little bits of casing dust and metal shavings bouncing around in there that should finish the job nicely. Hard drives rely on almost unimaginable precision to do what they do at the speeds they do, Any physical damage to the media surface is potentially fatal to the drive in a big way that nobody is going to recover. Places like drivesavers can do amazing things, but alot of what they do is based on having the ability to move platters to working drive bodies and software that can do detailed reconstruction of corrupt file systems. Broken platters are just not ever going to hold together in any meaningful way to be readable again and even of you could read a scrap, because of file fragmentation, you will often only have 1/3 of a file on that scrap and its not a readable scrap. ---
**Author:** ![AaronX](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@AaronX](https://boards.straightdope.com/u/AaronX)\ **Post date:** [August 29, 2012, 6:22am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/39 "2012-08-29T06:22:31Z")
After degaussing, is the drive reusable, or are the formatting marks gone? ---
**Author:** ![FoundWaldo](https://avatars.discourse-cdn.com/v4/letter/f/dfb087/32.png) [@FoundWaldo](https://boards.straightdope.com/u/FoundWaldo)\ **Post date:** [August 29, 2012, 6:35am UTC](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942/40 "2012-08-29T06:35:55Z")
DBAN is great when you have a computer that will take the drive you want to wipe. But I recently came across a box full of old SCSI drives (with various connector types, out of old Macs, Sun workstations, SGIs, etc. I’ve had over the years). For the vast majority of them, I don’t own a single machine (or external enclosure) that will take the drive. And for the few that would work in a machine I still have, the computer isn’t a PC so it can’t run DBAN (though yes, of course, there are other ways of wiping drives). Easier to just physically destroy them. [Previous page](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942.md?page=1) [Next page](https://boards.straightdope.com/t/hard-drive-destruction-how-much-to-assure-unreadability/632942.md?page=3)