I often work with circuit boards at my job. I don’t do anything special, I mainly just clean them and screw them into their housings. But when we clean them, we completely soak them into alcohol over and over again until they are spotless. How does this not damage the circuit board or the components on the board? Yet if I drop my phone in water, it will ruin it.
In: Chemistry
Water is conductive.
Alcohol isn’t, and evaporates.
I… just… you WORK with circuit boards?!
This isn’t necessarily the case.
Distilled water isn’t likely to damage electronics because pure water by itself has poor conductivity. However the electronics should be dried thoroughly and in short order, to prevent water trapped in small gaps and cavities from causing corrosion.
Tap water generally has enough dissolved salts, known as Electrolytes, that it has significant conductivity. This can cause short circuits that destroy sensitive microchips.
Solvent grade alcohol is usually also produced by distillation, so it doesn’t tend to have any dissolved electrolytes either and is therefore not conductive. Moreover it evaporates much more quickly than water, and is less likely to cause corrosion.
Water has salts, calcium and magnesium deposits. These conduct electricity and can fry something even after the device is 100% dry (they don’t evaporate). Short-circuits kill the device.
Alcohol doesn’t conduct any electricity, has no salts and impurities (most of the time), and evaporates very fast. Probably brings impurities along with it because it’s a strong solvent.
I should’ve tried washing out wet electronics with alcohol to get the salts out. A pro tip for wet phones is sticking it in a sock and spinning it until you force the water out via centrifugal force.
I used to work for Supra (Later purchased by Diamond Multimedia), they made modems. Whenever we had one returned to be fixed, one of the first things we did was run them thru a dishwasher. No detergent, just tap water. Once they dried, we worked on them. Never had any fail from water damage.
You can clean electronics with water too. The important thing is that they’re not powered at the time, and that the board is completely dry before power is applied.
Alcohol evaporates very quickly, so cleaning a board with alcohol ensures it’s going to be dry very fast.
Water tends to hang around for a very long time and to dissolve all sorts of junk on the board that make it more conductive. And that’s where you run into trouble. Modern devices have all sorts of nooks and crannies that are very good at keeping some small amount of water in, so if you spill water on a device it’s likely that water is going to remain inside it for days.
[You can put a keyboard through a dishwasher](https://www.youtube.com/watch?v=pgnF42ZoRSw) for instance, if you make sure it’s well dried after that before plugging it in.
I’m no expert, but my thoughts are that while cleaning the boards they are not energized. If you put your phone in water it is energized, and creates a short circuit between the components on the board.
Water has minerals dissolved in it which cause that. Alcohol doesn’t and neither does pure water. So if you were to use pure elemental water nothing would happen as well.
There’s two pieces to this.
First: alcohol doesn’t conduct electricity as well as water does, so it’s less likely to transfer any static electricity on the board into something important.
Second: presumably these boards are powered off, so that really wouldn’t be a concern in the first place. Alcohol evaporates quickly and completely, where water might lay damp on the board long enough to cause rust or other damage.
The reason behind it is the difference in the property of the liquid.
Water and it’s molecules have the property to conduct electricity due to a “plus and minus pole”, whereas high grade alcohol is non conductive (the molecule structure doesn’t allow for pole formation).
Additionally water is corrosive to most metals, meaning that a lot of metals will form oxides (iron & rust or copper & the green patina) which do not have original pure metal structure and property.
Alcohol (high grade/percentage) on the other hand has the ability to degrease due to the simular structure to fats.
Short answer: because water conducts electricity but alcohol doesn’t.
The real danger water poses to electronics is that it creates shorts between electronic pathways. If the device is turned on while these pathways are shorted, you end up with the wrong voltage or current getting to sensitive parts and damaging them. These pathways are very small and often quite close together, so it only takes a tiny droplet to create a dangerous short. Since alcohol doesn’t conduct electricity, it can bridge these pathways without danger.
That’s pure alcohol, of course. In practice the alcohol you’re using probably has some water in it (pure alcohol is hard to produce and thus very expensive). I’m not entirely sure here, but in assuming this is okay because (a) the amount of water is very small, and (b) alcohol evaporated w very quickly in air taking at least some of that water with it.
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