Washing the computer

[stan]

About once a year I take my laptop out to the garage remove all cover panels and use a air compressor set at about 40 psi to blow the dust out. I have noticed that it runs a lot cooler after.

Stan

[pnodrog]

They generally use rather specialised liquids to clean circuit boards after manufacture. One that springs to mind is mixes like safewash 2000. The aim is to remove flux residues and water is unlikely to do that even though de ionised water is pretty aggressive stuff in an odd sort of way - it just doesn't like being that pure so will dissolve small amounts of all sorts of things rather rapidly. Distilled water on the other hand for some reason I have never understood is far more stable - it doesn't rapidly take up CO2 from the air for instance and go acidic. I believe low grade de ionised water is used as a final wash at times but calling that de ionised is a bit misleading.

Personally I wouldn't be too concerned depending on what was on the board in dunking in soapy water in the sink and then swilling it off under the tap. Might not be a good idea if it has a fan for instance as it would take a long time to dry out internally.

Distilled water sounds fine to me but I would be inclined to mix in say 30% IPA to help it wet out and evaporate. The A in IPA would help removed greasy deposits as well.

De Ionised water - a long time ago I wondered why industrial chemists didn't use it rather than preparing distilled or even triple distilled water - one showed me why. Anecdotally I have heard that a few have made their coffee with de ionise water and managed to get mercury poisoning from their fillings. Pass, no idea but it is odd stuff.

John
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Having trained as a chemist before I got into electronics my washing the board with distilled water was not as brave or foolhardy as some of you may have thought...

John is correct that distilled or de ionsed water alone is pretty useless for removing the older solder flux. Most electronic boards are now either flow soldered or use solder paste soldering techniques leaving a minimal amount of flux that generally need not be removed.

De ionising water only removes salts etc most organic contaminants remain. e.g. If you de ionise vinaigrette (not sure who would want to do this) the salt and vinegar (ascetic acid) will be removed from the water but the olive oil and fine ground pepper will not. If you carefully distill vinaigrette the most volatile liquid fraction (water BP 100 deg C) will distill off first and then the when the temperature exceeds 200 deg C the olive oil will start to be distilled. If you stop collecting the distillate before the distillation temperature rises to over 102 or so degrees C the distillate will be fairly pure water.

I am sure you all wanted this bit of info for future reference although it is slightly more relevant to preparing film developer rather than digital photography.

[pnodrog]

I like the museum in your town very impresive history about the people who settled there.

Hi Peter, I am glad you enjoyed my local museum. I understand Donald has also visited it. Hopefully you enjoyed the rest of your journey to New Zealand as well.

[ST1]

Hi Peter, I am glad you enjoyed my local museum. I understand Donald has also visited it. Hopefully you enjoyed the rest of your journey to New Zealand as well.

We really did enjoy our time in NZ, if I was 21 again I wouldn't hesitate to move there. That's if they would have me of course