I've been working on my first silent computer (not just quiet--silent), but it's a P120 so it's not worth me spending any money on it. Becuase I'm using a literally beat up PSU with no working fan, the only moving parts in it are the loud hard drive.
So...I tried to figure out a literally ZERO cost hard drive silencing solution which both silenced the drive and adequately cooled it. I came up with a brilliant idea that ALMOST worked.
The concept: Passive water cooled hard drive in a bucket with packing peanuts
The theory: For the ultimate in silencing, a composite foam-like matrix of dense material and air is ideal. However, this is also makes for an ideal insulator--IF the dense material is solid. My brilliant "aha" was to make the dense material liquid water and form the matrix structure with packing peanuts forming air pockets. The water would still be able to flow to convect away heat while the complex structure would block sound.
The practice: I got myself an enclosed bucket to implement this with. The bucket must be enclosed because otherwise the packing peanuts will just float and pop out the top. I tested an 864M Maxtor in the bucket with just the packing peanuts. It was only slightly quieter with the lid open--packing peanuts alone don't absorb sound well. It was significantly quieter with the lid closed, so that you had to put your ear up to the bucket to hear it--but this solution was surely very bad for cooling...
...then I poured in the water with a funnel. As it filled up, I could feel the upward pressure on the lid due to the packing peanuts wanting to float up. I powered up the computer, and...silence! Yippee!
...Umm...hard drive failure...uh oh...
I pulled the drive out to see what happened. I tried to power the computer on, and the drive made a horrible "clack clacking" that I always associate with dead/about-to-die drives. As Dr. Bones would say, "He's dead, Jim."
My first instinct was that my Ziplock sandwich bag wasn't watertight enough. I took the drive out...and it was dry.
So what killed the drive? In restrospect it seems obvious--water pressure killed it. There was no way for the drive's internal air pressure to equalize with the outside water pressure (which has a vertical differential due to the density of water). This pressure surely warped the large flat top/bottom of the drive chamber, preventing the platter from spinning properly and consequently damaging the bearings when I powered it on. Possibly, the drive arm was also bent and/or applied excessive pressure to the platter.
Conclusions: Water pressure and hard drives don't mix. I still think this concept has some merit, given a way to isolate the hard drive from direct water pressure.
One way to kill a hard drive--water pressure!
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Ralf Hutter
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It's absolutely impossible to equalize the pressure, because water is dense and air is not. In the air filled drive chamber, there's practically no pressure differential between the topmost and bottommost points. In the surrounding water, there is a pressure differenctial between those points. I'm confident that even if the drive were prefectly horizontal to minimize the pressure difference, the forces would still warp the drive chamber enough to prevent reliable operation.
My two current ideas are:
1. Put the drive in a "pressure jar", and using fan inside the jar to circulate air. This jar is submerged in the water/packing peanut composite as before to silence it.
or
2. Put the water/packing peanut composite in a "jar", sitting on top of the large flat side of the drive to cool it. The remaining 5 sides of the drive are surrounded by sand in the bucket to silence all around.
My two current ideas are:
1. Put the drive in a "pressure jar", and using fan inside the jar to circulate air. This jar is submerged in the water/packing peanut composite as before to silence it.
or
2. Put the water/packing peanut composite in a "jar", sitting on top of the large flat side of the drive to cool it. The remaining 5 sides of the drive are surrounded by sand in the bucket to silence all around.
I really, really doubt that the water pressure killed your drive.
There's just not enough pressure to "squash" the drive.
According to your theory there was so much pressure that it physically bent the drives outer shell, causing it to contact either the arm or the platter. That would require a lot of force. You can pick up a running HDD and squeeze it in your hands, twist it, push on the top lid, poke it with a stick....and you still won't cause contact between the lid and the platter or arm.
My bet: Static charge from the ziplock bag. Or some water got in and made contact across a couple of traces on the PCB. (you'd only need one drop)
There's just not enough pressure to "squash" the drive.
According to your theory there was so much pressure that it physically bent the drives outer shell, causing it to contact either the arm or the platter. That would require a lot of force. You can pick up a running HDD and squeeze it in your hands, twist it, push on the top lid, poke it with a stick....and you still won't cause contact between the lid and the platter or arm.
My bet: Static charge from the ziplock bag. Or some water got in and made contact across a couple of traces on the PCB. (you'd only need one drop)
Hmm...I don't know what killed the drive. In any case, I don't have any more <1G drives lying around to test with. Anything 1+G is useful enough for me that I don't care to risk sacrificing them without knowing what killed the first victim.
My silent computer project has thus turned in a more traditional direction--network boot.
My silent computer project has thus turned in a more traditional direction--network boot.
Funny you should try something like that... I was curious about the effects of water pressure as well and did a vaguely related experiment. What I did was inflate a ziplock bag as best I could with my Garmin GPS unit inside. It has a built in air pressure sensor that reads to the tenth of a millibar. I filled up my kitchen sink (about 10" deep) and pushed the very boyant and well pressured bag to the bottom of the sink full of water. The pressure rose from something like 970mb to 973mb. It was pretty minimal, probably because the bag still permits some deformation.
Part 2 was to squeeze the ziplock as much as possible just to see what kind of reading I could manage; I achieved something like 1041mb (equal to something like 1500 feet below sea level) at the point where the bag felt like it was about to explode.
Most hard drives are rated to operate from -1000 to +10,000 feet. That's a range of around 1030 to 700mb of pressure. They also are designed to be able to withstand small amounts of continuous vibration, shock, heat, and so on. My guess is that something else caused the failure. I don't think it's physically possible to create a pressure situation that would cause drive failure in anything less than probably 15-20 feet of water.
By the way, if you want old hard drives, I probably have 4 laying around right now, anywhere from 213mb to I think a 3.2gb. UPS shipping is probably cheap on stuff that small and light if you really wanted to do more testing. I certainly have no use for them any longer.
Part 2 was to squeeze the ziplock as much as possible just to see what kind of reading I could manage; I achieved something like 1041mb (equal to something like 1500 feet below sea level) at the point where the bag felt like it was about to explode.
Most hard drives are rated to operate from -1000 to +10,000 feet. That's a range of around 1030 to 700mb of pressure. They also are designed to be able to withstand small amounts of continuous vibration, shock, heat, and so on. My guess is that something else caused the failure. I don't think it's physically possible to create a pressure situation that would cause drive failure in anything less than probably 15-20 feet of water.
By the way, if you want old hard drives, I probably have 4 laying around right now, anywhere from 213mb to I think a 3.2gb. UPS shipping is probably cheap on stuff that small and light if you really wanted to do more testing. I certainly have no use for them any longer.
Those made of cornstarch do; those made of polystyrene (styrofoam) do not. BTW, the cornstarch ones usually look like cheese puffs, and you can eat them. I recommend setting one on your tongue and seeing if it dissolves before chowing down, just in case you've got a cheese-puff-style styrofoam one.Nate wrote:Unrelated to the failure, but AFAIK, packing peanuts dissolve in water.
Disclaimer: don't try this at home. If you do, don't sue me.