How Silica Gel Took Over the World

> Benford was brought in to help calculate the probability that someone or something would intrude on the site for as long as it remains dangerous — approximately the next 10,000 years. It turns out, few things (outside of organized religions and ritualized traditions) last that long.

What a weird thing to say. No organized religion or ritualized tradition has ever lasted that long.

Every time I stumble onto it I have to resist not buying five gimmicky things.

self explanatory, it's dessi-can instead of dessi-cant

Why not?

Why ask why? Try Bud Dry.

How about a cleaning chemical packaged to look like fruit juice? Fabulous.

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.

"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.

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.

Why not demineralized water instead of alcohol?

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

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.

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

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

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.

I use them in my car against condensation.

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

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

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.

Throw them in a container with some silica gel.

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

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.

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.

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

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.

Getters can hold tight vacuums for several decades, even! I have many vacuum fluorescent displays from the 70s still working perfectly. As long as the getter spot is shiny and not white, it is holding vacuum fine.

Clearly, you can just put the window in the microwave for a few seconds to refresh it ;-)

I've seen these in imported Asian products, especially from China and Japan. Biscuits and similar dry snacks.

I've never seen it for a European product.

The Gimme-brand seaweed snacks I get contain oxygen absorbers. So do packages of Tillamook Country Smoker jerky and meat sticks.

They seem to be fairly common with packages of jerky and other self-stable cured meats.

There are both. Oxygen absorbers are used for moist snacks, apparently.

Bacon bits, fried onions, beef jerky.

> I think it started with a Z.

zeolite? https://en.m.wikipedia.org/wiki/Zeolite

My kids loved that stuff when they were young.

I don't know where you are in Europe, but from my experience basketball is popular in France and courts are everywhere.

I'd love to say that my comment was some commentary on the weirdness of the units, but really, it just stuck out to me, and I thought it'd be funny if I treated "gridiron football field" as the imperial system equivalent unit to the metric "basketball court" unit.

I rarely make comments on HN that are mostly just humorous and not actually intending to be on-topic... but every once a year or so.

Soccer fields don't have a standard size, however, so you're not going to be able to give a true comparison.

What do you mean they don't exist. I see them everywhere, indoor, outdoor, also every single school gym regardless of level is also a basketball court. I've lived in 3 countries here east & west Europe and this is valid across different places and cultures.

Yeah don't. Like many metals, finely dispersed iron can self-combust on air. I'd suggest an air-tight packaging filled with CO2, or, if your food is susceptible to acid, N2, if at all feasible. Industry uses additives similar to hydroquinone, mixed directly into, e.g., plastics. Plenty of them are food-safe, but I wouldn't know where to buy them if you aren't a business.

I think a lot of us might even confuse the two. The packets look fairly similar too.