Horrific stain on chassis door.

So my friend asked to use some of my compressed air to clean his pc, I told him the normal don't shake it and what not..... Next day he tells me he has a white stain on his chassis door. Advice?
 

Oussebon

Multiverse Poster
If it's a stain, it would likely wipe off. It could be that the plastic has been discoloured by the gas coming out as liquid.
 

ubuysa

The BSOD Doctor
I've come across this before, in fact I've damaged plastic components doing this. It is essential to use low pressure compressed air for cleaning computers. If you get hold of a high pressure can of air it is cooled to below freezing point as it comes out of the nozzle (that's how a fridge cooling plate works of course) and the extremely low temperature air has likely damaged the plastic. I wrecked a satellite phone on the boat doing this. I was attempting to clean the connector in the bottom of the phone where it fits into the docking station. The high pressure super-cooled air made the plastic extremely brittle and it disintegrated as I plugged it back into the dock. The result was a new phone.

I rather fear that the mark on your fiends case is not a stain it's permanently damaged plastic....
 

Tony1044

Prolific Poster
I've come across this before, in fact I've damaged plastic components doing this. It is essential to use low pressure compressed air for cleaning computers. If you get hold of a high pressure can of air it is cooled to below freezing point as it comes out of the nozzle (that's how a fridge cooling plate works of course) and the extremely low temperature air has likely damaged the plastic. I wrecked a satellite phone on the boat doing this. I was attempting to clean the connector in the bottom of the phone where it fits into the docking station. The high pressure super-cooled air made the plastic extremely brittle and it disintegrated as I plugged it back into the dock. The result was a new phone.

I rather fear that the mark on your fiends case is not a stain it's permanently damaged plastic....

Ditto. Plus some of those cans when inverted propel a freezing liquid when inverted which can add to the damage.
 

Oussebon

Multiverse Poster
Not sure that info is easily available. Also, the more you use, the lower the pressure. And why do you want to know the exact pressure? :)
 

ubuysa

The BSOD Doctor
how do you know the pressure of a can of compressed air?

Two ways....

One, read the label. If it doesn't say something like low pressure, or specifically for cleaning computers, I'd pass on it. If you buy one that you're not sure of then spray it onto a metal key (or anything metallic) and then immediately feel the temperature of the key where you sprayed. That will tell you how cold it gets. It it's more than just a little cool I'd not use it on anything electronic nor near plastic.

Two, you can get cans that you pressurise yourself with a little pump handle on the side. If you see one of those then get it.

On the boat I have an air horn (for giving fog signals) that you pressurise with a bicycle pump. I actually use that to clean my laptop and PC. I just remove the nozzle from the horn (it's LOUD) pressurise it with the pump and then use that to blow away the dust.....

It's unwise to blow yourself to clear the dust, and not least because you don't want to be inhaling that stuff, but also because air from your lungs is moist, often containing water droplets, and moist air is the last thing you want inside a PC. Anything that will give a gentle blast of air will do, even a regular car tyre foot pump would do.
 
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