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The guy at the local PC hardware store told me it's better to use a small hand-held leaf blower to blow dust out of your PC case than a hand-held vacuum cleaner. Why is this? I understand that fans might be damaged if they "spin too fast", but surely this is a problem with both vacuuming and blowing dust away... I imagine both machines would generate a small amount of static to be discharged carefully, so I can't see how one would be "safer" than the other?

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migrated from serverfault.com Apr 14 '11 at 11:12

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A leaf blower? This is a joke, right? Ever heard of pressurized air? It comes as a handy spray can. And this works better to get dust out because a vacuum cleaner will usually not pick up the dust "sticking" to the surface because it is not strong enough. Also, these spray cans have small tubes that can reach every corner. –  SvW Apr 14 '11 at 8:48
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Yes, I've heard of pressurised air. I'm just asking about what my local PC shop guy told me. Besides, pressurised air is quite expensive in South Africa –  Amanda Apr 14 '11 at 9:02
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up vote 26 down vote accepted

You can use both. Before ditching my desktop collection, I used to clean them using a six-gallon air compressor and a vacuum. Compressed air is much better at dislodging dust. As Nanne said, though, don't get your fans spinning too fast or you'll be generating current to be sent to your mobo. I usually use a finger to hold the fan in place while blasting it with air.

Anyway, unless you have a space away from where the computers normally live to clean their insides, you'll want to use a vacuum to suck up all the dust dislodged by the compressed air. Otherwise you're just going to end up with a bunch of dust in the air which the computers will pull right back into the chassis after you've powered them back on. I use short blasts of air to give the vacuum time to get the dust.

Without a vacuum, though, just use compressed air in a different, non-computer room.

Edit about the vacuum: You don't want to get it close enough to zap electronics; as others have mentioned those nozzles (plastic especially) can generate charge enough to zap things. You just want to capture the dust kicked up by the compressed air, not clean the components directly. Thanks to everyone who pointed that out.

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So if you generate current to be sent to your mother board while it is powered off; what harm will that do? –  JD Isaacks Apr 14 '11 at 13:19
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+1 for explaining why spinning up the fans could potentially damage the mobo. –  kivetros Apr 14 '11 at 13:32
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@John Isaacks: The fans spin by applying voltage to create movement. The opposite is also true: applying movement to the fan blades will create voltage, like a little generator. The motherboard is not really designed for that, so it's best to avoid it. –  Cakemox Apr 14 '11 at 14:13
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Does anyone have any first or second-hand experience with a spinning fan killing a mobo? Because I gotta say, that's the most entertaining part for me. –  Joe Apr 14 '11 at 15:01
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@Joe: It's always fallen under the "better safe than sorry" category for me, but now I'm curious, too. Gotta dig up the multimeter for some MythBusters: Exceptionally Nerdy Edition. –  Cakemox Apr 14 '11 at 15:09
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Do not suck. A vaccuum cleaner will produce a static charge, with all bad effects. Buy a can of pressurized air, and blow the dust out. Indeed, take care not to start turning your fans to hard, but that problem would also be there when sucking.

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This is a serious problem, made worse by the fact that static accumulates on the nozzle, and because it's sucking it's actively pulling itself towards the vulnerable components. In addition, a blown column of air is more coherent than a sucked volume, which makes it more effective per unit volume of air moved. –  regularfry Apr 14 '11 at 14:37
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If you are using a vaccuum for this in a workbench scenario, you could always add a wire to the nozzle and attach it to earth ground, effectively removing the risk. Your electronics workbench does have an earth ground on it right? I'd hope so or this entire topic is worthless. –  Kevin Peno Apr 14 '11 at 16:57
    
That would not work for plastic nozzles ofcourse? –  Nanne Apr 14 '11 at 18:23
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True, but if you "ground" (and I use the term loosely for non-conduction surfaces) a plastic nozzle on one side, the other side could just as well have some potential that gets discharged if you get close to that side. You would have to 'ground' the complete thing, practically making it iron all over, wouldn't you? If the nozzle is big enough it could still be a problem. I just don't see how you would ground a non-conduction nozzle... –  Nanne Apr 14 '11 at 19:19
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@Nanne: It's tough to say without actually running some tests, though my gut tells me that it is likely that the risks are low. However, you could also easily fashion a conductive mesh sleeve around the nozzel I suppose to remove that risk. –  Kevin Peno Apr 14 '11 at 20:14
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A vacuum might be alright for slightly dusty computers but I use compressed air. Not those silly overpriced little cans, which do a poor job at the best of times, but from a proper air compressor. To protect the fans I hold the blades while blowing into or very near the fan.

Just one thing to be careful of when using compressed air, don't hold the nozzle too close to the computer. I keep it back about a foot or so. Get too close and you can unseat most components, including RAM and CPU.

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Down side of using an air compressor is they do not filter out water and debris that can be expelled from an air compressor, not good for electronics. –  Moab Apr 14 '11 at 15:43
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@Moab most modern air compresssors will have a air/water separator attached, or you can buy one and put it on –  Scott Chamberlain Apr 14 '11 at 17:00
    
@ Scott, I have looked at and purchased many compressors, consumer grade compressors don't typically come with a filter or moisture trap. Its Just a warning as air compressors spew water and contaminants out after they have been used for a while. –  Moab Apr 14 '11 at 17:22
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For computers it doesn't matter too much; there is a danger that you can force dust into places it wouldn't otherwise go, but other than that, not a big deal. Fans will go bad on their own time, whether you like it or not. Static isn't much of an issue. Just leave it plugged in, and it'll ground out harmlessly.

NEVER EVER EVER USE BLOW ON A PRINTER. ALWAYS SUCK. ALWAYS Old school impact printers can handle dust, but they're about the only ones. Inkjets are more tolerant, but print heads are pretty fragile, and it can screw them up pretty badly. If you blow dust around in a laser printer, you're likely to push some up into the optics. If you do that, they basically have to be replaced and your print quality goes straight to hell.

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Was he selling small hand-held leaf blowers?

I think this question is going to delve deeply into the realms of the subjective. Several points of physics come to mind as pros and cons for both sides, and a the net win might depend a lot on the individual vacuum or blower.

Personally, I think I'd go for the vacuum to clean out the case and any large deposits so they don't get blown around the room, then the blower to dislodge dust and get it out of all the internals thanks to it's much higher air volume and velocity. The second part I would still do with a vacuum handy to keep the work-space clean and filter it out of the air too.

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Well, there's the other thing - I need to clean about a dozen computers, and I'd really rather do it in place... so blowing dust around the office doesn't really appeal to me. And no, he wasn't selling any leaf blowers ;) –  Amanda Apr 14 '11 at 9:04
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Use the vacuum for the big stuff, then keep the vacuum running and close but use a can of air to dislodge the stuff the vacuum won't move on it's own. –  Caleb Apr 14 '11 at 9:18
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As vacuuming doesn't remove all clogged dust, I'm fond of a small preassure tank with an airbrush nozzle that can deliver both narrow and wide air flow. One can blow 3-4 computers with a single refill.

To tackle the floating dust, I either use a table-top vacuum or electrostatic feather duster, depending on the shape and size of the case. When cleaning a server rack that can be opened from both ends, have another person hold the duster on the opposite end. Don't take the duster too close to the case to avoid static charges!

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I mostly use a compressor and then blow it away with an airgun, this is the only way to get all dust loose (well, atleast at 10bars it does)...

When there are large dust gatherings a vacuum cleaner would also do...

As for the static... don't worry to much, just turn the machine and powersupply off BUT DON'T UNPLUG IT, this way the machine stays connected to the ground wire and is able to discharge if any static charges might occur, But honestly, the chance of a static charge forming so big it would actually damage components is minimal...

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I use a vac to get most of the loose stuff out of the way. All that dust feels nasty when it gets on my skin. Just be careful not to whack the vac tools into the components. Air cans with nozzle straws are great for knocking the dust off heatsink fans though.

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My preference is definitely blowing, as it's simply much more effective. However, it's messy and pointless if you're indoors. If you're unable to take the machine outside to do your blowing, you're better off using a vacuum cleaner. You can buy static-neutral vacuum cleaners with useful attachments that are specifically designed for this type of indoor work.

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