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nvader 2 days ago

I didn't find this in the article, so:

You can "recharge" silical gel by baking in the oven at 120 C for a couple of hours. If you do, be careful to remove the casing before you do, unless it is heat safe.

I have a small collection of oven safe dessicant packs that I keep on hand for emergency drying electronics.

Workaccount2 2 days ago | parent | next [-]

You are better off soaking the wet electronics in isopropyl alcohol then trying to dry them in a bag full of desiccant.

One of the things that kills wet electronics is the dried residue that is left behind, creating shorts. Alcohol will wash away the water and leave no residue after it dries.

If the device has ink or glue you'd like to try to preserve, deionized water will mostly work too.

nyanpasu64 2 days ago | parent | next [-]

One time I tried drying a water-soaked smartphone in alcohol, but the alcohol got under the LCD screen and made it look blotchy permanently. The phone still worked but I stopped using it.

nicoburns 2 days ago | parent | next [-]

I think the protocol would generally be to disassemble the device and then clean with alcohol. Easier said than done with a phone of course.

owenversteeg a day ago | parent | prev [-]

Yeah, I've had the same issue; as far as I can tell it's not actually the LCD itself but the backlight and the diffuser that end up getting screwed up. If you're trying to save electronics, keep the isopropanol away from the screen.

hilbert42 2 days ago | parent | prev | next [-]

"You are better off soaking the wet electronics in isopropyl alcohol."

Where I am ethanol (EtOH-95%, H2O-5%) is much cheaper and much more readily available and works almost as well. If silica gel is not available, then a fan works well followed by a warm (not hot) oven baking. Make sure the alcohol has essentially all evaporated first.

Keep in mind that some components can be affected by both EtOH and propan-2-ol — component markings, coil doping resins can dissolve, etc. Both alcohols are also good at removing solder flux resins/residues. (Oh for the days when freon and freon mixtures were available, component damage never happened.)

Devices with power transformers pose special problems, best to dry with alcohol first (hoping enamel coatings on wire aren't softened), then bake in oven on warm heat for a long while, sometimes 24 hours or more is necessary. With transformers it's important that this is done as soon as possible after wetting.

Edit: as I'm reminded by nyanpasu64 keep both alcohols away from LCD screens (likely all screens). I had a netbook PC and put it in a carry bag with a bottle of EtOH and it leaked. The PC still worked but the screen suffered the same outcome.

SirHumphrey 2 days ago | parent [-]

That may be country specific, but at least where I live, ethanol is much more expensive than isopropyl alcohol (30€/l vs 10€/l) - mostly because of dues on ethanol.

hilbert42 2 days ago | parent | next [-]

Right, if you live where duty is applied to ethanol then it's expensive. In Australia, where I am ethanol is available as a denatured product. That is, it includes a very small amount (much less than 1%) of denatonium (aka Bitrex) which renders it undrinkable (it's the bitterest substance known). As such, excise tax is not levied.

Here, one liter bottles of denatured ethanol are available in every supermarket everywhere, and up to 20 liters available in hardware stores (at bulk rates it's even cheaper).

For comparison, here denatured ethanol costs about $5/l [in US dollars] versus isopropyl at between $25 and $30/l.

DebtDeflation 2 days ago | parent [-]

In the United States, if you buy "Denatured Alcohol" at a big box store, it will be a toxic brew of often 50-60% methanol as well as smaller amounts of MEK, MIBK, and even acetone in addition to the ethanol. However, you can order "Specially Denatured Alcohol (SDA)" from various chemical suppliers or even Amazon. "SDA 40B 200" will be 99.5% ethanol with 0.1% tert-butyl alcohol and 0.0005% denatonium benzoate. It's what I use for camp stove fuel since I refuse to carry methanol in my pack with food.

hilbert42 2 days ago | parent [-]

I understand the problem with purchasing EtOH in the US. Frankly, I consider adding MeOH, MEK, etc. to denature it as both dangerous and an archaic procedure. (Moreover, outside lab reagents, MeOH should never exist without denatonium, it's just too dangerous.)

Some people will drink EtOH whether it's denatured with MeOH, etc. or with the much safer denatonium. Why blind or kill these people when one doesn't need to? Sure, EtOH will likely get them anyway but why should the State be their executioner?

There's something awfully wrong with that I reckon.

InDubioProRubio 2 days ago | parent | next [-]

Puritan wrath, a nice mixture of hatred of ones own ant-existance and hatred on others not participating the labour camp race to the bottom, thats why?

0_____0 2 days ago | parent | next [-]

Typically I would dismiss this as a bit overwrought but I came back from overseas last week and promptly was forced to drive in Boston, an activity that both takes place in the heart of US puritanism and perfectly encapsulates something that is frustrating in a way that could only happen in a place where "it's shit, it's supposed to be shit, and if you don't like it, there's the door" is a core principle.

hilbert42 2 days ago | parent | prev [-]

Right, I was being polite, my question was rhetorical.

a day ago | parent | prev | next [-]
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1oooqooq 2 days ago | parent | prev [-]

it's cheaper and the free market is regulating itself as god intended.

gpderetta 2 days ago | parent | prev [-]

Isn't the ethanol denatured? There's a duty on that as well?

hilbert42 2 days ago | parent [-]

It is, with denatonium hence no excise tax.

lightedman 2 days ago | parent | prev | next [-]

At my work any electronics that have had a water bath or flux-added rework will get an ultrasonic alcohol bath and then a forced air drying run. Alcohol is just so damned good for so much.

fellerts 2 days ago | parent | next [-]

I'd be very scared of IPA in an ultrasonic cleaner. Sounds like a recipe for a fire. Or is your machine perhaps designed for safe IPA cleaning?

jdietrich 2 days ago | parent | next [-]

A few companies do make ultrasonic cleaners that are designed for flammable solvents, but they aren't common.

The easiest option is to just fill a plastic food bag with solvent, throw your part in, seal it with a clip and float it in your ultrasonic bath. The bag contains the vapour for safety, and it's easy to switch between different solvents and solutions.

0_____0 2 days ago | parent | next [-]

That's a quite elegant solution I hadn't considered before.

adolph 2 days ago | parent | prev [-]

That is next generation sous vide. Just controlling temperature is ho-hum. Getting it to just the right ultrasonic vibration to "cross-modulate the adipose frequency" is next level.

And someone is already doing it:

https://besservacuum.com/en/ultrasonic-food-treatment-machin...

benjijay 2 days ago | parent | prev | next [-]

I'm scrolling before coffee and initially took your acronym as India Pale Ale, which would certainly be a different cleaning experience...

hilbert42 2 days ago | parent | prev | next [-]

I've used both EtOH and propan-2-ol (IPA) for decades in ultrasonic cleaners both at room temperature and heated (quite warm to feel but not boiling hot) and never had a problem with fire.

Retr0id 2 days ago | parent | prev | next [-]

Do ultrasonic cleaners get hot?

adlpz 2 days ago | parent | next [-]

I've run isopropyl alcohol in an ultrasonic cleaner.

It did get significantly hot after a while. And smelly, so it was surely aerosoling (is that a word?) somewhat.

I did it outdoors and away from anything that could catch fire because it felt rightly sketchy.

numpad0 2 days ago | parent | prev | next [-]

It's basically an industrial ultrasonic humidifier attached to the bottom of a buffet tray. And it does get warm.

bradyd a day ago | parent | prev | next [-]

A lot of ultrasonic cleaners have a heating element.

actionfromafar 2 days ago | parent | prev [-]

Typically not (though some have heaters you can apply) but they atomize the fluid pretty well. The tiniest spark (static electricity) and some bad luck and you have the lid shooting into the roof and then a fire. As with everything, if you know what you are doing, go ahead.

nullc 20 hours ago | parent | prev | next [-]

Even more spicy is vapor phase cleaning... evaporate the solvent, condense on the part to be cleaned suspended above it. Very effective since the impurities are constantly distilled out.

Also kinda explody.

lightedman a day ago | parent | prev [-]

The machine doesn't get hotter than 50C. IPA isnt igniting at that temp.

wkat4242 2 days ago | parent | prev | next [-]

I totally agree though my use of it is pretty different ;)

dieselgate 2 days ago | parent | prev [-]

What percentage alcohol is used?

lightedman a day ago | parent | next [-]

99%. 70% if I'm doing parts disinfection for medical devices.

arcmechanica 2 days ago | parent | prev [-]

usually 99%

2 days ago | parent | prev | next [-]
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noname120 2 days ago | parent | prev [-]

Why not demineralized water instead of alcohol?

Numerlor 2 days ago | parent [-]

Alcohol would dry up faster, demineralised water will have more time to dissolve and redeposit particles. Though you have to be careful with alcohol as it can destroy some plastics

Graziano_M 2 days ago | parent | prev | next [-]

You can just microwave them too, on low power. It's much, much faster and power efficient.

mrob 2 days ago | parent | next [-]

Also much harder to control. Oven drying has the advantage that you can set the temperature so there's no risk of overheating anything.

geor9e 2 days ago | parent | next [-]

I do microwave. It's pretty easy to not burn, just undershoot it - 10 seconds, see how hot it is, another 10 seconds. Once it's blazing hot shake it back and forth to get the steam off. If it's the colored kind (white when good, pink/blue when full of water) it's easy to tell when it's good. Takes about 30 seconds all together - I recharge my dessicant packs before every use. Of course, people are welcome to spend hours doing the oven method if they want. I just don't personally see an advantage, unless you have an industrial amount of packs to recharge.

lazide 2 days ago | parent [-]

FYI, but some desiccant coloring agents are cancerous

JohnBooty a day ago | parent | next [-]

Yeah. Unless it's advertised as "food grade" and has a specific "Cobalt chloride free" I would def. not put it in food -

These fit the bill. Assuming they're not straight-up lying or anything...

https://www.amazon.com/Rechargeable-Desiccant-Dehumidifiers-...?

hilbert42 2 days ago | parent | prev [-]

It's cobalt chloride—the same stuff that used to be used on those little weather indicators where a little man or woman would pop out to indicate whether it was going to be wet or dry. They usually had a spot of blotting paper about 2cm round soaked in it. Cobalt chloride is blue when dry and pink when damp.

All ionic cobalt salts are toxic so cobalt chloride is not used as an indicator in silica gell packaged for use with food. That said, it's an excellent indicator for telling whether your silica gell is still working or not.

lazide 2 days ago | parent [-]

Silica gel for industrial purposes sometimes is soaked in it as an indicator.

lugvruzzle 2 days ago | parent | prev [-]

is there any harm in overheating silica when drying it out?

pumnikol a day ago | parent | next [-]

Pure silica? It's really just SiO2. It might kind of fragment/ burst if it has a lot of water absorbed and you heat it too fast. Then everything in the vicinity would get sprinkled with fine dust which you shouldn't inhale in large quantities, as it might cause silicosis.

2 days ago | parent | prev [-]
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Klaster_1 a day ago | parent | prev [-]

This is what I do to dry 3D printer filament silicagel. Handling all those small beads without spilling some is finicky, but works good enough.

imglorp 2 days ago | parent | prev | next [-]

Practical details about the types of desiccant beads and how to dry them.

https://www.youtube.com/watch?v=6tHInlFfMcM

neilv 2 days ago | parent | prev | next [-]

Can someone speak authoritatively on how safe/unsafe it is to put the silica gel packets with cobalt chloride indicator into the oven?

(By default, I've been assuming it's not sufficiently safe.)

adrian_b 2 days ago | parent | next [-]

Cobalt chloride decomposes only at extremely high temperatures and it melts only at very high temperatures (726 °C), which could not be reached, in any case not before all water in the silica gel would be converted to steam and it would be eliminated. Even when no water is left, it is unlikely that the beads with cobalt chloride could absorb enough microwave energy to be heated at very high temperatures.

So by itself cobalt chloride could not cause any problem.

However, I have no idea whether the cobalt chloride is not mixed with some organic binder, to make it stick to the silica gel beads, which could burn in the oven, though that is also unlikely to happen before all water is removed from the gel, allowing an increase in temperature above the boiling temperature of water.

By using low microwave power and short time, so that no boiling of the contained water should be seen, it should be possible to dry even beads with cobalt chloride.

eternityforest 17 hours ago | parent [-]

Are there studies on whether it sheds dust and under what conditions?

Also, where are people even still getting cobalt chloride gel? Do they still make it? I sure wouldn't buy any.

I wouldn't even buy the orange to green stuff by choice these days for anything DIY, it's still too toxic when mechanical hygrometers are cheap.

ender341341 2 days ago | parent | prev | next [-]

There's silica gel you can buy without cobalt chloride that I use for storing my 3d print filament.

neilv 2 days ago | parent [-]

I also do this. I'm wondering whether anyone needs to be warned about cobalt chloride, or it's innocuous.

jdietrich 2 days ago | parent | prev [-]

If you're concerned, the orange/green silica gel is non-toxic.

jchw 2 days ago | parent | prev | next [-]

I use dessicants for 3D printing. I've heard you can dry them out safely by just microwaving them for a few seconds. I wonder if that's good enough.

bayindirh 2 days ago | parent | next [-]

You can get the ones with indicators, which change color according to how saturated they are.

You can check the color to see whether it's time to microwave them, and whether they are dry once you microwaved them.

abracadaniel 2 days ago | parent [-]

The indicator is supposed to be toxic though. I’ve always seen warnings to never reuse that kind.

adrian_b 2 days ago | parent [-]

If the indicator is cobalt chloride, which is blue when dry and pale pink (possibly almost invisible) when wet, that can be toxic or carcinogenic when ingested in great quantities, or when you inspire a lot of dust of it, but it is not dangerous to handle when in compact form.

It is certainly not something like a poison, where small quantities can have harmful effects, at least not for most people.

Like nickel, cobalt can cause allergies in some people, in which case repeated exposure can have serious effects even in small quantities, in those humans who are sensitive to it.

bgnn 2 days ago | parent | prev [-]

I use them in my car against condensation.

The instructions on tge cover say 3 minutes at 700W in the microwave.

moebrowne 2 days ago | parent | prev | next [-]

They can also be died at much lower temperatures, it just takes a lot longer. I dry mine by leaving them on top of a computer at ~35C for a week, I believe the air flow from the fans is important.

The color indicating ones are useful so you can see when they are dry.

timerol 2 days ago | parent [-]

At what ambient humidity do you do this? Where I am we are having a dry day at 45% humidity today. Tomorrow it'll be over 90%, and it'll stay between 50% and 90% through the weekend. I would expect that you need a more consistently dry environment for this to work

2 days ago | parent | prev | next [-]
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nemonemo 2 days ago | parent | prev | next [-]

This sounds like a great idea, but how do you keep it from being "drained" or hydrated?

wildzzz 2 days ago | parent | next [-]

Immediately take them out of the oven and store in the smallest airtight container you have. Obviously they'll absorb the humidity in the container and whatever is introduced anytime you open it. Ideally, keep them in containers that have an excellent seal and minimal internal volume like quality ESD bags.

thfuran 2 days ago | parent [-]

I don't think I've ever seen an antistatic bag with a very good seal, and I'm not sure it's a good idea to drop something directly out of a hot oven into them either.

cma 2 days ago | parent [-]

Another option is a canning jar.

dredmorbius 2 days ago | parent [-]

For the quantities of silica gel typically used, a smaller spice or condiments jar (glass with metal lid) would be more appropriate for most people.

singleshot_ 2 days ago | parent | prev | next [-]

Throw them in a container with some silica gel.

jonah 2 days ago | parent | prev | next [-]

In a "ziplock" bag which you have vacuumed all the air out of.

NoahKAndrews 2 days ago | parent | prev | next [-]

If they're not getting hydrated slowly, they're not serving any purpose. The whole point is that water goes into them instead of whatever you're trying to keep dry.

mrob 2 days ago | parent | next [-]

If you're keeping them on hand for drying electronics in emergencies then you need to store them somewhere airtight.

filoleg 2 days ago | parent | prev [-]

I think the grandparent comment meant keeping unhydrated during storage (for future uses of emergency drying electronics), not while it is being actively used for its intended purpose.

reverendsteveii 2 days ago | parent | prev | next [-]

other people are suggesting the microwave rather than the oven. to my mind it seems very possible that you don't keep them from hydrating, you just dehydrate them on-demand.

mrob 2 days ago | parent | prev [-]

I store mine in an plastic box with airtight lid designed for food storage.

nvader 2 days ago | parent [-]

Precisely this! Even so, I refresh them just before using them.

TIL about the microwaving trick. I'll have to find out more about it. My concern would be the gel beads popping from internal pressure.

JohnFen 2 days ago | parent | prev [-]

I use a food dehydrator for this, but the principle is the same.

nvader 2 days ago | parent [-]

When my last phone took an unsanctioned swim, my research suggested that a food dehydrator is a last resort. It risks forcing water vapour further into the electronics of the system, rather than encouraging it to move out.

I did find a clever solution online that tried to induce mechanical suction on your phone to force the vapour out, but it was too expensive for a one off use.

In the end I had to resort to the food dryer anyway, after the silica gel failed to work.

JohnFen 2 days ago | parent [-]

I've never used it for drying wet electronics. The couple of times I've dunked my phone, I've just let it air-dry for a couple of days and it's been good.

I use silca gel for storing 3D printing filament and long-term clothes storage.