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Old January 26th 17, 08:29 PM posted to alt.comp.hardware,microsoft.public.windowsxp.general
mike
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Default Damage a case fan by vacuuming air vents from the outside?

On 1/24/2017 3:01 PM, VanguardLH wrote:
micky on 2017/01/23 wrote:

In alt.comp.hardware, on Mon, 23 Jan 2017 11:23:18 -0800, pyotr
filipivich wrote:

mike on Mon, 23 Jan 2017 04:20:19 -0800 typed in
microsoft.public.windowsxp.general the following:
On 1/23/2017 1:37 AM, micky wrote:
Can you damage a case fan by vacuuming the air vents from the outside?

(I have a Dell Optiplex 775 with the original fan. )

It seems more than safe to me, but I happened to read the manual for a
Noctua fan and it says not to use a vacuum cleaner or it may apply
"excessive force to the fan". I find that hard to believe. I've pushed
on the vanes of other 3, 4, and 5" fans and they don't bend at all with
the kind of force vacuum cleaners exert. In fact I think they would be
hard to break. Are Noctua fans more fragile than others?


I think the case fan is rarely the problem.
I buy all my computers at garage sales. I've never, ever
had a case fan that had a dirt problem.
I've had MANY CPU fans 100% blocked with cat hair.

If you think you've got dust, take it apart and blow it
out with compressed air,

Use the canned stuff. Don't take it into the shop and blow it out
with air from the 120 psi line - with or without the inline oiler.


What about the grease gun? Where do I use that?

I don't have a 120 psi line, but I have the image of a can of air having
no more force than a spray can of paint or bug spray. Is that really
enough to move the dust, some of which I think is sort of stuck to
whatever it's stuck to?


Well, what ELSE is inside a can of spray paint? Oh yeah, the emulsified
particulate solution AND the propellant. So obviously the can cannot
contain only propellant. What happens as you use up the propellant in a
spray paint can? Yep, the pressure goes down. You know that a can of
spray paint will get colder as the propellant gets converted from high
to low[er] pressure. A can of compressed air will frost over and get
too cold to hold after only using part of the can. The canned air will
also wane in pressure as the propellant gets used up but you are
starting with a hell of a lot more propellant.

Also, the nozzle of a spray paint can is designed to mist (aerate) the
emulsified particulate, not spew it out as fast as it can. The flow
rate is throttled and turbulence is deliberate increased to produce a
more even spray pattern.

By the way, you are probably more accustomed to those fixed or
non-refillable air cans, like you get at a typical computer or hardware
retail store.


I think you're confusing compressed air with a phase-change propellant.
You can't get enough compressed air into a "duster" can to do anything
useful. You can use air pressure to dispense a small percentage
volume of
payload, like paint, but the pressure varies considerably as you use it up.
The downside is that phase change propellants useful at human
temperatures and spray can pressures have side effects, like
flammability or ozone depletion
or toxicity.

I've use compress air cans that have a micro-adjustable
nozzle that you screw onto the can (first you slide a collar on the
spray head onto a rim on the can and then screw down the delivery tube
onto the can. That is needed due to the much pressure of those cans.
In fact, you can puncture your skin if you open the valve all the way up
on a new can using the smallest aperture nozzle size. Typically those
air sprayers are not supposed to be full open. They are adjustable for
flow rate and have a large weighted trigger to direct a more exact and
consistent pressure at the nozzle tip. Those are expensive. You don't
find them in computer or hardware stores. The cans can be repressurized
with a pump. I got some from a friend that worked at Medtronics in the
QA and failure analysis labs.

I just use the simple non-refillable cans at the computer and hardware
stores. You've never used one of those? If you did, you wouldn't think
they were anywhere as near the throttled low flow rate of spray paint
cans of which only a portion of their volume is the propellant.