Chemistry

119 Articles

Tech In Plain Sight: Super Glue

December 11, 2023 by 68 Comments

Many inventions happen not by design but through failure. They don’t happen through the failure directly, but because someone was paying attention and remembered the how and why of the failure, and learns from this. One of these inventions is Super Glue, the adhesive that every tinkerer and engineer has to hand to stick pretty much anything to anything, quickly. Although it was a complete failure for the original uses it was developed for, a chemist with good memory and an eye for a helpful product created it in a process he described as “one day of synchronicity and ten years of hard work.”

Super Glue was initially invented in 1942, when the chemist Harry Coover was working on a team trying to develop a clear plastic gun sight that would be cheaper than the metal ones already in use. The team cast a wide net, trying a range of new materials. Coover was testing a class of chemicals called cyanoacrylates. They had some promise, but they had one problem: they stuck to pretty much everything. Every time that Coover tried to use the material to cast a gun sight, it stuck to the container and was really hard to remove. 

When the samples he tried came into contact with water, even water vapor in the air, they immediately formed an incredibly resilient bond with most materials. That made them lousy manufacturing materials, so he put the cyanoacrylates aside when the contract was canceled. His employer B. F. Goodrich, patented the process of making cyanoacrylates in 1947, but didn’t note any particular uses for the materials: they were simply a curiosity. 

It wasn’t until 1951 when Coover, now at Eastman Kodak, remembered the sticky properties of cyanoacrylates. He and his colleague Fred Joyner were working on making heat-resistant canopies for the new generation of jet fighters, and they considered using these sticky chemicals as adhesives in the manufacturing process. According to Coover, he told Joyner about the materials and asked him to measure the refractive index to see if they might be suitable for use. He warned him to be careful, as the material would probably stick in the refractometer and damage it. Joyner tested the material and found it wasn’t suitable for a canopy but then went around the lab using it to stick things together. The two realized it could make an excellent adhesive for home and engineering use. Continue reading “Tech In Plain Sight: Super Glue” →

Custom Fume Hood For Safe Electroless Plating

October 22, 2023 by 10 Comments

There are plenty of chemical processes that happen commonly around the house that, if we’re really following safety protocols to the letter, should be done in a fume hood. Most of us will have had that experience with soldering various electronics, especially if we’re not exactly sure where the solder came from or how old it is. For [John]’s electroless plating process, though, he definitely can’t straddle that line and went about building a fume hood to vent some of the more harmful gasses out of a window.

This fume hood is pretty straightforward and doesn’t have a few of the bells and whistles found in commercial offerings, but this process doesn’t really require things like scrubbing or filtering the exhaust air so he opted to omit these pricier and more elaborate options. What it does have, though, is an adjustable-height sash, a small form factor that allows it to easily move around his shop, and a waterproof, spill-collecting area in the bottom. The enclosure is built with plywood, allowing for openings for an air inlet, the exhaust ducting, and a cable pass-through, and then finished with a heavy-duty paint. He also included built-in lighting and when complete, looks indistinguishable from something we might buy from a lab equipment supplier.

While [John] does admit that the exhaust fan isn’t anything special and might need to be replaced more often than if he had gone with one that was corrosion-resistant, he’s decided that the cost of this maintenance doesn’t outweigh the cost of a specialized fan. He also notes it’s not fire- or bomb-proof, but nothing he’s doing is prone to thermal anomalies of that sort. For fume hoods of all sorts, we might also recommend adding some automation to them so they are used any time they’re needed.

Continue reading “Custom Fume Hood For Safe Electroless Plating” →

Copper Be Gone: The Chemistry Behind PCB Etching

August 31, 2023 by 33 Comments

For a lot of reasons, home etching of PCBs is somewhat of a dying art. The main reason is the rise of quick-turn PCB fabrication services, of course; when you can send your Gerbers off and receive back a box with a dozen or so professionally made PCBs for a couple of bucks, why would you want to mess with etching your own?

Convenience and cost aside, there are a ton of valid reasons to spin up your own boards, ranging from not having to wait for shipping to just wanting to control the process yourself. Whichever camp you’re in, though, it pays to know what’s going on when your plain copper-clad board, adorned with your precious artwork, slips into the etching tank and becomes a printed circuit board. What exactly is going on in there to remove the copper? And how does the etching method affect the final product? Let’s take a look at a few of the more popular etching methods to understand the chemistry behind your boards.

Continue reading “Copper Be Gone: The Chemistry Behind PCB Etching” →

The Briny Depths Give Wine An Edge, But How?

August 27, 2023 by 61 Comments

Though Hackaday scribes have been known to imbibe a few glasses in their time, it’s fair to say that we are not a wine critic site. When a news piece floated by about a company getting into trouble for illegally submerging crates of wine though, our ears pricked up. Why are vintners dumping their products in the sea?

Making wine, or indeed any alcoholic beverage, starts with taking a base liquor, be it grape juice, apple juice, barley malt solution, or whatever, and fermenting it with a yeast culture to produce alcohol. The result is a drink that’s intoxicating but rough, and the magic that turns it into a connoisseur’s tipple happens subsequently as it matures. The environment in which the maturation happens has a huge influence on this, which is one of many reasons why wine from the cellar of a medieval chateau tastes better than that from an industrial unit in southern England. The Californian company was attempting to speed up this process by leaving the bottles beneath the waves. Continue reading “The Briny Depths Give Wine An Edge, But How?” →

Kitchen Steganography With Turmeric

August 26, 2023 by 12 Comments

It is a classic rite of passage for nerdy kids to write secret messages using lemon juice. If you somehow missed that, you can’t see the writing until you heat the paper up with, say, an old-fashioned light bulb. If you were a true budding spy, you’d write a boring normal letter with wide spacing and then fill in the blanks between the lines with your important secrets written in juice. This is a form of steganography — encoding secret messages by hiding them in plain sight. [Randomona] shares a different technique that seems to be way cooler than lemon juice using, of all things, turmeric. This isn’t like the invisible ink of our childhood.

That’s probably a good thing. We doubt an LED bulb makes enough heat to develop our old secret messages. [Ranomona’s] ink doesn’t use heat, but it uses a developer. That means you must make two preparations: the ink and the developer. The results are amazing, though, as shown in the video below.

Continue reading “Kitchen Steganography With Turmeric” →

Supremely-tough Glass Performs Under Pressure

August 24, 2023 by 25 Comments

There’s some nifty research from the University of Bayreuth, together with partners in China and the U.S., on creating supremely tough aluminosilicate glass that boasts an unusual structure. The image above represents regular glass structure on the left, and the paracrystalline structure on the right.

Aluminosilicate, which contains silicon, aluminum, boron and oxygen, is a type of oxide glass. Oxide glasses are a group to which borosilicate and other common glasses belong. Structurally speaking, these glasses all have a relatively disordered internal structure. They’re known for their clarity, but not especially their durability. Continue reading “Supremely-tough Glass Performs Under Pressure” →

Different Etching Strokes For Different PCBs, Folks

August 8, 2023 by 44 Comments

[Sebastian] probably didn’t think he was wading into controversial waters when he posted on his experimental method for etching PCBs (in German). It’s not like etching with hydrochloric acid and peroxide is anything new, really; it was just something new to him. But is it even possible these days to post something and not find out just how wrong you are about it?

Sadly, no, or at least so it appears from a scan of [Sebastian]’s tweet on the subject (Nitter). There are a bunch of ways to etch copper off boards, including the messy old standby etchant ferric chloride, or even [Sebastian]’s preferred sodium persulfate method. Being out of that etchant, he decided to give the acid-peroxide method a go and was much pleased by the results. The traces were nice and sharp, the total etching time was low, and the etchant seemed pretty gentle when it accidentally got on his skin. Sounds like a win all around.

But Twitter wouldn’t stand for this chemical heresy, with comments suggesting that the etching process would release chlorine gas, or that ferric chloride is far safer and cleaner. It seems to us that most of the naysayers are somewhat overwrought in their criticism, especially since [Sebastian]’s method used very dilute solutions: a 30% hydrochloric acid solution added to water — like you oughta — to bring it down to 8%, and a 12% peroxide solution. Yes, that’s four times more concentrated than the drug store stuff, but it’s not likely to get you put on a terrorism watch list, as some wag suggested — a hair stylist watchlist, perhaps. And 8% HCl is about the same concentration as vinegar; true, HCl dissociates almost completely, which makes it a strong acid compared to acetic acid, but at that dilution it seems unlikely that World War I-levels of chlorine gas will be sweeping across your bench.

As with all things, one must employ caution and common sense. PPE is essential, good chemical hygiene is a must, and safe disposal of spent solutions is critical. But taking someone to task for using what he had on hand to etch a quick PCB seems foolish — we all have our ways, but that doesn’t mean everyone else is wrong if they don’t do the same.

Continue reading “Different Etching Strokes For Different PCBs, Folks” →