Growing sodium chloride crystals at home | Hacker News Reader

Growing sodium chloride crystals at home

crystalverse.com

198 pointsbehnamoh62 comments

Tried growing them after this post made it to the HN last time.

Killed about two months on this and nothing good came out of it. Got some crystals, sure, but definitely nothing that is even in the same ballpark as in the post.

It all sounds simple, in principle, but requires skills and experience. Like making a good carbonara or decent croissants. It's all in the technique.

> It's all in the technique.

Sounds like the technique was not fully documented then.

This post didn't dwelve on the fact your water needs to be pure - if you've got hard water, it's not going to work.

Try again but with demineralized water - often sold in supermarkets to avoid scaling in clothing irons.

You might also want to look into the effect of vibrations in the room where your experiment takes place.

Would distilled water work or does it need to specifically be "demineralized"?

Distilled water is fine. Demineralized is normally cheaper and also fine.

Distilled water is effectively demineralized... Not perfect... technically it's collected steam from boiling water, so it kills most bacteria and leaves most other material or minerals that can't be carried by steam.

I hadn't considered that steam could carry tiny particles of minerals, but it's obvious now that you point it out. So demineralized water would probably be closer to pure H2O. I've never noticed demineralized water at my grocery store, but maybe that's just because I've never looked. But I will next week!

microplastics and forever chemicals both show up in clouds and rainwater, so I'm guessing they're both in distilled water, but I wonder if at least the microplastics are removed from demineralized water

In the USA it is almost always labeled distilled water.. I've never seen "demineralized water" advertised as the alternate methods are relatively new (at a competing price point).. but they would likely just be called purified, and you'd have to look at the label.

Purified water may or may not be demineralized, depending on the method used to purify.

Basically any other form of bottled water is about as regulated as homeopathic remedies... Short of killing people, nobody really watches them. This is part of the reason why distilled water is recommended for home medical use like CPAP machines or Neti pots, with purified as second best (though it COULD be equal or better, the term is too generic)

I did use demineralized water!

Then I'd guess they grew too fast, or the salt was unsuitable somehow, maybe iodised, maybe an anti-caking agent.

Growing crystals like in the article requires low enough ambient temperature that they can grow for a month or more without running out of water.

I wonder if it's a container cleanliness issue. I can imagine dishwasher detergent residue might leave trace chemicals that mess up the formation.

I also wonder if the smoothness of the container has an effect. A rough surface might encourage lots of seed sites.

Yes, this is an issue, with more than just soap residue.

At the very least, all containers used for growing crystals should pass the water break test. That requires substantially better cleaning than a casual wipe down with an old sponge & some dish soap.

Did you document your failure? I'm honestly curious -- the author of the post mentions some of their false starts, but I think a description of what you tried and what didn't work could be valuable (even if you didn't do an extensive root cause analysis). There are a lot of Monday-morning quarterbacks here trying to suggest what you did wrong, but unless someone has tried and failed themselves I don't think there's a lot of value in the feedback.

I've had really good results using this guide. Grew some proper crystals.

Getting the evaporation right is important. It can't be too fast or too slow. I grew my crystals in a closet.

When I read about growing crystals online, I always have to think of the old 4chan "prank" that under the promise of beautiful crystals instructs the unsuspecting reader to brew some chloramine gas.

Safe for Work screenshot of post: https://imgur.com/IKQRKqv

If I remember correctly it originated on the private site LUElinks before spreading.

…which I just found out shutdown last year. RIP

It's still alive in some form - the user database was migrated and old accounts can be accessed on the new site through a per-user token. If you had an account you may still be able to get the token and get into the new site. I haven't finished the transfer myself, though.

This seems like Attempted Murder.

Nah, bro, it's just a prank.

On a more serious note, it's a small wonder sodium hypochlorite is not yet regulated as, say, potassium permanganate, considering its various uses.

Technically, everything can be used to kill.

You can stuff toilet paper into someones mouth until they choke to death on it.

Should we regulate the sale of toilet paper to prevent potential murders?

I don't know, should we? Over here, potassium permanganate became a regulated substance only about 10 years ago so I wouldn't be surprised if in 10 more years, sodium hypochlorite too stops being sold over the counter.

Now, lest this comment of mine becomes too upvoted, here is another controversial take to counterbalance it: some things can be used almost exclusively only to kill people, like guns, unlike knives. Yes, you can stab or cut someone with a knife, but you can stab or cut many other things than humans for useful and helpful effects while the gun allows you too... put small, deep holes into things from a distance, with not-so-great accuracy? At the very best, you can sit in an arm-chair with your hair-trigger and a hundred Boxer cartridges, and proceed to adorn the opposite wall with a patriotic V.R. done in bullet-pocks, but I feel strongly that neither the atmosphere nor the appearance of your room would be improved by it.

This is pretty funny, though I hope nobody actually tried this.

to be clear this may kill you and any other nearby people

Previous discussion:

How to grow sodium chloride crystals at home - https://news.ycombinator.com/item?id=29255511 - Nov 2021 (184 comments)

Despite seeing this before it’s always a joy to be brought back to this site. It feels like the old internet did in terms of content, but has the high quality presentation that the modern internet is capable of. It’s a real treat.

This was posted before ages ago, and I suspect I know the answer, but I have to ask -- has anyone here successfully done this?

I had grand designs to use ethanol as an anti-solvent to accelerate crystal growth, and I bet you can guess how much progress I made towards that goal. Maybe I've lost my hacker mojo entirely and should be expelled from this site forever.

[1] https://en.wikipedia.org/wiki/Sodium_chloride#cite_ref-28

Yes I've grown some great salt crystals using this guide and little effort.

> ethanol as an anti-solvent to accelerate crystal growth

You usualy want something that evaporates very slowly to get big nice crystals.

I want to know how to grow a silicon ingot at home.

Easy:

1. Build a quartz crucible inside an inert argon atmosphere

2. Heat it to 2600F/1400C

3. Melt your highly pure silicon in it

4. Add in a seed at the top that the rest of the silicon can crystalize around

5. Now comes the tricky part that requires some experimentation: Pull out the seed very carefully while rotating it, so that an ingot forms around it as you keep pulling

An even easier approach: if you want a 40cm ingot, you can just take a 80cm one that you grew before, and cut it in half

How do you cut it?

With a diamond saw.

Step one to making one of those is to compress and heat some carbon...

I genuinely think that was one of the more amusing exchanges I found on HN. There is just such a weird level of.. it could very well be a deadpan joke, but also a well-meaning, helpful response.

it's like the advice on how to become a millionaire. start with a billion dollars, and start investing.

This made me realize that I don't mind humor in HN comments when they're genuinely clever.

This is opposed to what you often see on Reddit where the "funny" comments are just chains of some meme/common phrase and display no ingenuity (though, to be fair, I did once find those comments funny).

I didn't actually know how silicon wafers were cut before, so it was actually somewhat informative.

Followed your instructions, but I can't seem to get a wafer size larger than about 88cm diameter. What am I doing wrong? Can anyone help?

Well, clearly your first problem is that you want it to be that large in the first place. 30cm ought to be enough for everyone, if it's good enough for TSMC it's good enough you.

Everyone knows TSMC can't make the newest AI chips that have to multiply a 1,000,000,000x1,000,000,000 matrix every clock cycle. What if you're trying to compete with Nvidia?

Even 5 cm is more than enough for home use, or do you know a chip that is bigger?

https://www.cerebras.net/product-chip/

Who, then, can make them?

Tony Stark built this in a cave with a box of scraps!

Anyone got resources on how to grow crystal that are piezoelectric? Would be awesome to grow my own microphone or accelerometer.

Look up making Rochelle's salt, it's relatively straightforward to carry out in a kitchen using essentially the same equipment outlined in this article.

Great tip! Making Rochelle's salt definitely looks very doable. I found a video on YouTube that grew crystal and used it as mic on a guitar. Sounds pretty good to be honest! Though the form factor is a bit odd - a bulky crystal blob :D https://youtu.be/8QP7F1VT1rw?si=guMAa-oof6xQCgol

The first step says to use sea salt. I thought the defining feature of sea salt is that it was going to be a collection of minerals that happened to be dissolved in the ocean water collected that day.

Practically speaking I assume little impact, but would you not want to start with more pure NaCl?

Grow these around led bulbs...if that would work. For better visuals.

I don't know if it would work but it could be cool to have the individual filaments encased in crystal, something like these:

https://www.amazon.com/PRETYZOOM-100pcs-LED-Filament-Incande...

I accidentally grew some big crystals from copper plating electrolyte (copper sulfate). Nice blue color.

I hadn't seen this before. Will definitely try it. Knowing in advance that it might not work out.

That's great, but does anyone knows similarly accessible way of growing a fluorite crystal?

i'm guessing you can add dilute solutions of sodium fluoride and calcium chloride dropwise to a large beaker of water being constantly stirred, with a seed crystal in it? fluorite has a very non-negligible water solubility of 15 mg/liter and a reasonably high melting point, so intuitively i'd think this should be easy and fast

maybe the ingredients are hard for you to get tho, in which case you might be reduced to generating hydrogen fluoride from fluorite and an acid, then bubbling the gas into the beaker

the standard industrial method sounds like it would be pretty annoying to do in your garage:

> However single crystals for industrial applications are usually grown by solidification from a melt. The so-called Stockbarger-Bridgeman and the vertical gradient freeze processes are used for industrial manufacture of single crystals. The crystals are grown in a drawing oven and in a vacuum of 10^-־4 to 10^−5 mbar in the Stockbarger-Bridgeman method. A crystalline raw material is melted, so that a homogeneous single crystal is obtained with exacting control of temperature.

> In order to make the single crystals up to now the crystalline raw material is slowly heated in a vessel to the volatilization or evaporation temperature of water of about 400° C. and is maintained at this temperature in order to keep it free of water for some time. Additive scavengers, such as PbF2, SnF2 or ZnF2, are used to remove oxygen from the raw material. The added scavengers react with the oxygen present in the raw material and arising partially by oxidation and/or hydrolysis to form easily volatile oxides, which escape at these temperatures. After that a so-called refinement during a single week at 1450° C. usually is performed followed by a multi-week cooling to about 1200° C., in which the desired crystal is solidified from the melt. The single crystal so obtained is then cooled in a first slow cooling phase and then cooled to room temperature in a second accelerated cooling phase after the first cooling phase.

from https://patents.google.com/patent/US6364946B2/en

I did it in the first or second grade after the teacher showed us how to.

Is there a maximum size for a crystal?

Yes, eventually it will collapse into a black hole.

They can be very big, gor example https://www.bbc.com/travel/article/20220721-the-worlds-large... https://www.atlasobscura.com/places/giant-crystals-naica (Note that this crystals are not made of "table salt", they are made of "dehifrated paster". But in theory you can make crystals of table salt this big with enough time.)

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