salt

11 Articles

How To Grow Your Own Pyramid Salt Crystals

October 13, 2022 by 23 Comments

The regular granular table salt you’re used to isn’t the most attractive-looking seasoning out there, even given its fundamentally compelling flavor. You don’t have to settle for boring old salt anymore though, because [Chase] has shown us you can grow your own pyramid salt crystals at home!

Pyramid salt crystals can grow naturally, and typically occur in locations where salt pools are undisturbed under the warmth of the sun. However, it’s possible to grow them on purpose, too. As a bonus, their hollow structure means they dissolve very quickly on the tongue, and can taste “saltier” than typical granular salt.

To grow your own, you’ll need a bag of salt, which is mixed with some water. You’ll want to do so in a glass dish, as the salty solution you’ll be making can ruin metal cookware. The dish can then be heated up on an electric hotplate, which is used to heat the solution to between 60 and 70°C.

A small amount of food-grade potassium alum is also added to the solution to calm the convection currents in the heated solution, allowing the crystals to form gently without sticking and clumping together. As the water boils away, the rectangular-pyramidal crystals grow.

Naturally, you must be careful before eating the results of any home-grown lab experiments. However, [Chase] reports having licked some of the crystals and has confirmed they do indeed taste salty. [Chase] also notes several ways in which the parameters can be changed to grow different types of pyramid crystals, too.

We’ve featured [Chase]’s crystal-growing work before. If you’ve got your own cool DIY crystal projects cooking up in the lab, be sure to let us know!

Electric Chopsticks Bring The Salt, Not The Pain

April 21, 2022 by 12 Comments

The Japanese people love their salt, perhaps as much as Americans love their sugar high fructose corn syrup and caffeine. But none of these are particularly good for you. Although humans do need some salt in their diets to continue existing, the average Japanese person may be eating too much of it on a regular basis — twice the amount recommended by the World Health Organization, according to Reuters. Cue the invention of electric chopsticks, which provide salty flavor without the actual sodium.

No, you won’t get shocked — not even a fresh 9 V to the tongue’s worth. The tips of the chopsticks are made of something food-safe and conductive, and one is wired to a bracelet that contains a small computer. Using a weak current, the chopsticks transmit sodium ions from the food to the tongue, which increases the perceived saltiness by 1.5x. The device was co-created by a Meiji University professor and a Japanese beverage maker, who hope to commercialize it sometime next year.

This isn’t the first time humans have used trickery when it comes to diets. The older among you may remember the miracle berry weight loss craze of the 1970s. When ingested first, miracle berries make sour things taste sweet, so chowing down on grapefruits and lemons suddenly sounds like a good idea. What people failed to realize was that the acidity would still wreak havoc on their teeth and tongues, leaving them regretful the next day.

Images via Reuters

3D Printed Climbing Holds, Now With Texture

February 26, 2022 by 4 Comments

Technology enables all kinds of possibilities to mold our environments in the way we best see fit. Plenty of ski resorts use snowmaking to extend their seasons, there are wave pools for surfing hundreds of miles away from oceans, and if you don’t live near any mountains you can build your own climbing wall as well. For the latter, many have turned to 3D printers to create more rock-like climbing grips but plastic doesn’t tend to behave the same as rock unless you do what [Giles Barton-Owen] did and incorporate salt into the prints.

For small manufacturers, typically the way that the rock texture is mimicked is by somehow incorporating sand, permanently, into the grip itself. This works well enough but is often too rough on climbers’ hands or otherwise doesn’t faithfully replicate a rock climbing experience. For these grips, instead of including sand, salt crystals of a particular size were added to a resin that was formed over the 3D printed grip. Once the resin cures substantially, the water-soluble salt can be washed away leaving a perfect texture to grab onto with chalked hands.

While this might not be a scalable method for large-scale climbing grip manufacturers, [Giles] hopes this method will help smaller operations or even DIY climbers to build more realistic grips without having to break the bank. In fact, he has already found some success at his local climbing gym using these grips. The method may be more difficult to scale for larger manufacturers but for anyone who wants to try it out themselves, all that’s needed for this build is a 3D printer, salt, and time.

Continue reading “3D Printed Climbing Holds, Now With Texture” →

The (Sodium Chloride) Crystal Method

November 20, 2021 by 25 Comments

[Chase’s] post titled “How to Grow Sodium Chloride Crystals at Home” might as well be called “Everything You Always Wanted to Know about Salt Crystals (but Were Afraid to Ask).” We aren’t sure what the purpose of having transparent NaCl crystals are, but we have to admit, they look awfully cool.

Sodium chloride, of course, is just ordinary table salt. If the post were simply about growing random ugly crystals, we’d probably have passed over it. But these crystals — some of them pretty large — look like artisan pieces of glasswork. [Chase] reports that growing crystals looks easy, but growing attractive crystals can be hard because of temperature, dust, and other factors.

You probably have most of what you need. Table salt that doesn’t include iodine, a post, a spoon, a funnel, filter paper, and some containers. You’ll probably want tweezers, too. The cooling rate seems to be very important. There are pictures of what perfect seed crystals look like and what happens when the crystals form too fast. Quite a difference! Once you find a perfectly square and transparent seed crystal, you can use it to make bigger ones.

After the initial instructions, there is roughly half the post devoted to topics like the effect growth rate has on the crystal along with many pictures. There are also notes on how to form the crystals into interesting shapes like stars and pyramids. You can also see what happens if you use iodized salt.

If salt is too tame for you, try tin. Or opt for copper, if you prefer that.

How Researchers Used Salt To Give Masks An Edge Against Pathogens

December 19, 2020 by 32 Comments

Masks are proven tools against airborne diseases, but pathogens — like the COVID-19 virus — can collect in a mask and survive which complicates handling and disposal. [Ilaria Rubino], a researcher at the University of Alberta, recently received an award for her work showing how treating a mask’s main filtration layer with a solution of mostly salt and water (plus a surfactant to help the wetting process) can help a mask inactivate pathogens on contact, thereby making masks potentially re-usable. Such masks are usually intended as single-use, and in clinical settings used masks are handled and disposed of as biohazard waste, because they can contain active pathogens. This salt treatment gives a mask a kind of self-cleaning ability.

Analysis showing homogenous salt coating (red and green) on the surface of fibers. NaCl is shown here, but other salts work as well.

How exactly does salt help? The very fine salt coating deposited on the fibers of a mask’s filtration layer first dissolves on contact with airborne pathogens, then undergoes evaporation-induced recrystallization. Pathogens caught in the filter are therefore exposed to an increasingly-high concentration saline solution and are then physically damaged. There is a bit of a trick to getting the salt deposited evenly on the polypropylene filter fibers, since the synthetic fibers are naturally hydrophobic, but a wetting process takes care of that.

The salt coating on the fibers is very fine, doesn’t affect breathability of the mask, and has been shown to be effective even in harsh environments. The research paper states that “salt coatings retained the pathogen inactivation capability at harsh environmental conditions (37 °C and a relative humidity of 70%, 80% and 90%).”

Again, the salt treatment doesn’t affect the mask’s ability to filter pathogens, but it does inactivate trapped pathogens, giving masks a kind of self-cleaning ability. Interested in the nuts and bolts of how researchers created the salt-treated filters? The Methods section of the paper linked at the head of this post (as well as the Methods section in this earlier paper on the same topic) has all the ingredients, part numbers, and measurements. While you’re at it, maybe brush up on commercially-available masks and what’s inside them.

Take This 3D-Print Post-Processing Method With A Grain Of Salt

October 27, 2020 by 20 Comments

There’s a lot of folklore around post-processing of prints from FDM printers. Proponents swear by their methods, which are generally intended to either strengthen the part or to improve its appearance, or both. But do they actually work?

Knowing that a collection of anecdotes is no substitute for actual data, [Stefan] from CNC Kitchen has again performed some valuable experiments, this time testing the strength of parts that have been annealed in salt. This was a follow-up to his recent experiments with baking prints after entombing them in plaster, which yielded mixed results in terms of strength gains. Viewers commented that common salt makes a good medium for annealing prints, so he set about finding the right kind of salt. It turns out that the finer the grain, the better — powdery salt packs tighter and leaves little space for the softened plastic to flow — but that powdery salt is not easier to find. He ended up making his own by pulverizing table salt in a blender. He also had to play around with temperatures and times until coming up with a good process.

The results are impressive. PETG, ABS, and two varieties of PLA prints tested with force applied perpendicular to the print layers all showed marked increase in strength after breaking, to the point of nearly matching the strength of parts printed with the layers parallel to the stress. As with the plaster, parts were printed at 100% infill; a Benchy printed at 20% was notably unseaworthy after annealing. Surface finish on the annealed parts is an interesting combination of pitting with white residue — not unattractive but still a bit weird.

Salt annealing might be a bit cumbersome, but it’s a neat method to add to all the other post-processing tricks that people have come up with for their 3D prints. Continue reading “Take This 3D-Print Post-Processing Method With A Grain Of Salt” →

Reforming 3D Prints With Salt And Heat

September 23, 2020 by 83 Comments

The biggest problem with fused deposition 3D prints is that while the layers should stick together, they aren’t the same as a solid piece of plastic you would get from, say, injection molding. You can anneal plastic using moderate heat, but it is likely to cause the part to deform or change size. [Free Spirit 1] has a solution for this. Using a powdered salt, the part is packed on the inside and out and put in an oven. The results in the video below look really impressive.

In addition to making the part look solid and — we assume — adding strength, the resulting prints are also water- and gas-tight which was the purpose of the effort. That alone would make the technique worthwhile.

The only thing we noticed is that the part has to have access to hold the salt. Anything not supported would be subject to deformation. However, the ground-up salt is so fine that it should be relatively easy to fill in most parts and, of course, print with 100% infill to avoid hollow internal areas.

[Free spirit 1] used a coffee grinder to get the salt powder, but apparently you can buy “flour salt.” We wondered if other powders might work well, too. Apparently, sand didn’t work out, perhaps because the salt dissolves out in water, so whatever you use, it should probably dissolve in something that won’t attack your plastic.

Annealing isn’t a new idea, and we’d love to see some objective tests on this new method.

Continue reading “Reforming 3D Prints With Salt And Heat” →