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CDs shattering in high-speed drives?

zakur

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Z
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CD Shattering

CD Shatterring, a phenomenon also known as Exploding CDs, occurs when a high speed CD-ROM drive (48X or higher) shatters a CD with a loud cracking sound. Typically, the disk and the drive will be completely ruined after the incident. Furthermore, fragments of the broken disk can be expelled through the front cover of the drive at high speed and cause physical injury.
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Anybody ever experience this? I work in a public library and just heard from a colleague at another library that they've have been having trouble with CDs shattering in patron's newer computers. Apparently the new super high speed drives in combination with the library's older CDs, that have been played countless times, are a bad combination. One of their patrons, a computer-networking specialist who thought shattered CDs were just an "urban legend," had a library CD shatter in his computer, and a piece of it hit him in the knee.

Now they are seriously considering placing warning labels on all their CD-ROMs and music CDs.

I found this risk assessment that notes this type of failure is rare, but still recommends "that you consider whether you can reposition any affected computers so that the CD ROM drive is not positioned at the face level of the users." :eek:
 
Well, Mythbusters did a piece on this. Even made the discs shatter, but I'm not certain if it was while they were using a regular, if slightly gutted, drive or the powertool......
 
I saw that Mythbusters episode. It was definitely with a very high rpm power tool that they were eventualy able to shatter the CDs.

Mind you, they were testing with new CDs.

If I remember correctly, tinkering with a CD player to make it spin as fast as it possibly could was still several thousand rpm short of the 20,000 rpm needed to shatter the disks.
 
Molinaro said:
I saw that Mythbusters episode. It was definitely with a very high rpm power tool that they were eventualy able to shatter the CDs.

Mind you, they were testing with new CDs.

If I remember correctly, tinkering with a CD player to make it spin as fast as it possibly could was still several thousand rpm short of the 20,000 rpm needed to shatter the disks.
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I remember that episode. You summed up the results well.

The high speed camera footage was very cool. The disk was all like flippity-floppity then BOOM!

shatter CD all over the place.
 
I have had cracked CDs shatter in ordinary drives, although the drives weren't wrecked, I just had to spend a couple of hours taking them apart and removing the pieces.
 
They had one shatter that they had cooked in a microwave. They had the drive hooked up to a variable-speed router (if I recall correctly) because the computer they had couldn't get the drive to spin up to 48X speeds so they had to improvise.
 
CD's tend to pick up micro-cracks on the outside edge. This results from dropping the CD on it's edge, placing it in the tray with pressure to flex it a little bit and among things, poor fit on the spindle and the micro-fracture happens on the inside edge. And a higher speed drive will fire up the spindle so fast, it actually causes friction, like a tire spinning too fast on pavement, before it catches a full grip. Micro-flaws grow when that happens over and over. Drive spins down and stops to conserve power... spins up, ziiing, more stress on the micro-flaws.

And use over time makes those micro-fractures larger and longer. You acutually need a high power magnifying glass to see them, and even then, it's very hard. If you use a fiber optic to highlight a beam through the cd with the magnifying glass, you'll find them much easier. (Use sunglasses for a direct beam from the fiber optic won't hurt your eyes if it slips and flashes you.

And then of course, those higher speed drives can and will make them explode. Mythbusters should have found an older, more used CD, and then the results would have been more forthcoming.

Older and more used means more micro-fractures. After all, it's only a thin layer of transparent plastic.

:D
 
I think the problem with public library CDs is that they are very well-used, and therefore more likely to be scratched/cracked. Combined this with the security devices often not-so-precisely placed on them leading to an unbalanced spin.

Damaged CD + poorly balanced + high RPMs = POW!
 
I once had a CD shatter in my computer. I used stick on labels- the best that I could determine was that the label had come loose and stuck on something inside the drive. I've noticed that my library puts stick-on labels on CDs and DVDs.
 
Never happened to me but a coworker told me it happened to him. He said he heard a POP, like something blew up, then he was picking little chunks of CD out, I don't recall if he said the drive worked after.
 
Yes, CDs can explode. It happened to me, not a coworker or a friend, but me.

I was a few months into a new job doing development for portable devices. I was originally doing work for the PalmOS, but needed to do some work on Windows CE, so I needed to install ActiveSync. I was handed a really gnarly looking Microsoft ActiveSync CD that looked like it had been used as a frisbee. I threw it in the drive. The drive started to spin up, and then BANG. The door of the CD drive was blown off (actually just hanging on), and chunks of CD came out of the drive.

I was able to get about 60% of the remains of the disc out of the drive, and started to re-assemble the disc a la NTSB. I didn't have a digital camera, and the cleaning service cleaned all of the little bits up before someone who did brought a camera in.

The machine was on my desk rather than under, so my head was about 2 feet away from the drive. Scared the bejeesus out of me. Regardless of the Mythbusters results, it CAN happen. It just doesn't happen often.

BTW, the IT department replaced my drive without blinking an eye.
 
Molinaro said:
I saw that Mythbusters episode. It was definitely with a very high rpm power tool that they were eventualy able to shatter the CDs.

Mind you, they were testing with new CDs.

If I remember correctly, tinkering with a CD player to make it spin as fast as it possibly could was still several thousand rpm short of the 20,000 rpm needed to shatter the disks.
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I can personally confirm that an original of Roller Coaster Tycoon shattered inside my Alienware's cd drive. Don't recall if it was scratched or not, but it definitely shattered into dozens of little pieces, which I had to pick out one by one.

Those things spin so fast, and there's a noticeable hum and vibration, its obvious that something in the CD + spin mechanism is slightly off center.
 
As others have stated, it is possible for used CDs to crack and break inside of a CD-ROM drive while rotating at high speeds, especially if the CD is already micro-cracked or off-balance. This much is certainly believable. However, I have always had serious doubts about claims of injury resulting from this. In order for a person to be injured by a shattered CD, it would need to fracture and fly apart with sufficient speed and momentum to not only break apart the CD-ROM drive, it would also need to still have sufficient momentum and proper trajectory to fly free, strike the user, and pierce any clothing or skin that it may hit.

Realistically, I don't see that ever happening. As has been mentioned, Mythbusters did an episode where a CD did shatter, and the shards did seriously harm a ballistics gel dummy, but there were a few mitigating factors:

1) The CD wasn't in a CD-ROM drive, it was rotating exposed on a router.

2) The router was spinning considerably faster than any currently manufactured CD drive would be capable of spinning, even if your computer was pushing it to its maximum speed.

Those two factors alone are enough to show just how far someone would have to push a brand new CD to shatter in such a way as to be able to cause injury. Now, an older CD could certainly fracture with less difficulty because of wear related to use, but would it cause injury? Outside of good old fashioned urban legends, I seriously doubt it.
 
I've seen this happen as well in the workplace. The CD in questions had a tiny crack in the hub area which I'm sure led to it shattering. There was a shard of the CD sticking out about 1 inch out the back of the drive. But that shard was wedged in the slit between the top metal shell of the drive and the rest of the drive - it could not have punctured the metal itself. However, that shard had hit the front of the drive instead, where the plastic cover and drawer cover is, it's possible that it could have extended further or even come all the way out - but I can't see how it would have much force after that.


When I was young, I thought it might be interesting to see if it was possible to fold a CD without it breaking in two (bending it over so that opposite edges touched). Right about when the edges touched, it broke, but it didn't just snap in half. It shattered and broken plastic shards flew across the room. Fortunately I had it pointing away from my face or it's very possible I could have been injured.
 
Actually, the side of my computer case was open, but nothing flew out and hit anything. I had to partially disassemble the mechanism just to get at the pieces. A piece would have to not only make it out of the mechanism but also out of the computer case itself as well, quite an operation. Even an "auto-load" slot CD mechanism would probably not eject pieces out the slot.

Now I did see a video of an idiot who spun a CD at high speed using a Dremel-like tool, and then tossed a little thing into the CD, deliberately shattering it. High speed pieces just missed his face (and eyes) because they were, quite coincidentally, just outside the plane of rotation at the moment he tossed the item.
 
Fizzer said:
When I was young, I thought it might be interesting to see if it was possible to fold a CD without it breaking in two (bending it over so that opposite edges touched). Right about when the edges touched, it broke, but it didn't just snap in half. It shattered and broken plastic shards flew across the room. Fortunately I had it pointing away from my face or it's very possible I could have been injured.
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Heh.

There's a cheap brand of writeable CDs in Germany that I no longer buy. If you put a label on one of those CDs and flex it as descibed, the whole data layer will peel off.
 
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