Compressed air

[Sputnik]

The Giotto Rocket is only a few quid and never runs out.

That is a cool looking bit of kit. I have never seen one before.

[GoNz0]

That is a cool looking bit of kit. I have never seen one before.

they do work well and can be found dirt cheap on places like amazon, i think i got mine for £2 plus postage, about 7 or 8 quid all in.

trouble is while it can give a good swift blast of air in all reality there bloody useless for cleaning a pc unless you dont mind wa**ers cramp

end of the day there designed for a camera and your not meant to blast a camera with compressed air

[Pob255]

Here's a few points about air cleaning.

1 - Spray duster/compressed air
Are the same thing, they all use compressed non-flammable gas in the form of a liquid.
The cheap ones use a simple valve to release the gas and if they are not held upright (which it will say on the can) if held at an angle or upside down liquid will come out.
The more expensive ones are "invertible" there's a reservoir inside before the valve that allows the liquid to expand back into gas before leaving the nozzle.

The Icy residue you get from spraying the liquid is just that, ice, this occurs with all forms of gas compressed into liquid, to change state from liquid to gas requires a lot of thermal energy, the heat is sucked out of both the surface the liquid is on and the air around it, which causes moisture in the air to condense and freeze as frost.
You can get a similar thing happening with a compressor but not to the same level as air compressors are generally not powerful enough.

Basic physics - any gas that expands absorbs heat, State changes require exponentially more heat.

2 - Vacuum cleaners
The big danger from vacuum cleaners is not static, it's from fans.
Vacuum cleaners suck in a lot of air, and the big danger is spinning the fans with the suction.
The motor of a fan turns electrical current into rotational spin of the blades, however the opposite is also true, if you spin the blades it turns the motor which effectively becomes a dynamo and generates current.

The big issue is that the high volume of suction from a vacuum cleaner can spin the fan far faster than it normally runs at and the faster a fan spins the higher the voltage is generated (the opposite is also true which is why you reduce the voltage of a fan o slow it down)
If the fan is plugged in then you can end up feeding 24volts or more back into what ever the fan is connected too and you can often burn out a motherboard fan header at the minimum.

You can spin fans with cans of compressed air too, it's not such an issue with big fans as there's not enough power to spin them at high speeds, however small fans and blowers can be over spun, so you do need to be careful even with just compressed air.

You can get a cheap compressor, but they are generally not worth it unless you do a lot of air dusting.
eg at work I can end up cleaning out 10-15 projectors a year, each projector can take up to a whole can of compressed air (normally around half a can), went through about 7-10 cans in a year, so a cheap compressor was worth it.

One thing I would very much suggest is a small paint brush, use this to brush and loosen dust with compressed air/vacuum cleaner, you'll get far more off than just with air alone.

[OilSheikh]

£4 @ Wilkinsons.

You shake the can and then spray while holding the can upright-ish

[OilSheikh]

+ Other problem with a vaccum cleaner is that it can absorb your Jumpers!

[Giraffe]

How about a 1 litre pump-up sprayer (garden type)? Not excessive pressure and should last for ever.

I have seen a can that could be pressurised with a bike pump, so 7 Bar+ should be attainable!