Etching Large Brass Sheets Is Harder Than You Think

June 19, 2019 by Sean Boyce 32 Comments

One of my favorite ways to think of engineering is that a glass is not half empty or half full, only twice as large as it needs to be. As useful as that idea is, it also means that I rarely put any effort into the aesthetics of my projects – I learn or accomplish what I need, desolder and recycle the components, then move on. Few of my projects are permanent, and custom cases tend to be non-reusable, so I skip the effort and expense.

Once in a while though, I need to make a gift. In that case form and function both become priorities. Thankfully, all that glitters is not gold – and over the last year I’ve been learning to etch the copper alloys commonly classified as ‘brass’. We’ve covered some truly excellent etched brass pieces previously, and I was inspired to try and etch larger pieces of metal (A4 and larger) without sacrificing resolution. I thought this would be just like etching circuits. In fact, I went through several months of failed attempts before I produced anything halfway decent!

Although I’m still working on perfecting my techniques, I’ve learned enough in the meantime to give a report. Read on if you’re feeling the need for more fancy brass signs in your life.

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Perovskites: Not Just For Solar Cells Anymore

June 13, 2019 by Dan Maloney 21 Comments

If you’ve been around long enough, you’ll know there’s a long history of advances in materials science that get blown far out of proportion by both the technical and the popular media. Most of the recent ones seem to center on the chemistry of carbon, particularly graphene and nanotubes. Head back a little in time and superconductors were all the rage, and before that it was advanced ceramics, semiconductors, and synthetic diamonds. There’s always some new miracle material to be breathlessly and endlessly reported on by the media, with hopeful tales of how one or the other will be our salvation from <insert catastrophe du jour here>.

While there’s no denying that each of these materials has led to huge advancements in science, industry, and the quality of life for billions, the development cycle from lab to commercialization is generally a tad slower than the press would have one believe. And so when a new material starts to gain traction in the headlines, as perovskites have recently, we feel like it’s a good opportunity to take a close look, to try to smooth out the ups and downs of the hype curve and manage expectations.

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Loads Of Testing Yields New, Reliable, And Cheap Leather Hardening Technique

May 26, 2019 by Donald Papp 36 Comments

Leather hardening has been around for such a long time that one might think that there was little left to discover, but [Jason F. Timmermans] certainly showed that is not the case. Right around the end of 2018 he set up experiments to compare different techniques for hardening leather, and empirically determine the best options. After considerable effort, he crafted a new method with outstanding results. It’s part of his exhaustive testing of different techniques for hardening leather, including some novel ones. It was a considerable amount of work but [Jason] says that he gathered plenty of really useful information, which we’re delighted that he took the time to share it.

According to [Jason], the various methods of hardening can be separated into four groups:

Thermal: heat-treating at 180 ºF or higher, usually via some kind of boiling or baking process.
Chemical: soaking in a substance that causes changes in the leather. Some examples include ammonia, vinegar, acetone, brine, and alcohol.
Mechanical: hammering the leather.
“Stabilizing” methods: saturating the leather with a substance to add rigidity and strength without otherwise denaturing the leather itself. Examples include beeswax, pine pitch, stearic acid, and epoxy.

We recommend making the time to follow the link in the first paragraph and read the full results, but to summarize: heat-treating generally yields a strong but brittle product, and testing revealed stearic acid — which resembles a kind of hard, dense wax at room temperature — was an early standout for overall great results. Stearic acid has many modern uses and while it was unclear from [Jason]’s reasearch exactly when in history it became commonplace, at least one source mentioned it as a candidate for hardening leather.

But the story doesn’t stop there. Unsatisfied with simply comparing existing methods, [Jason] put a lot of work into seeing if he could improve things. One idea he had was to combine thermal treatment with a stabilizer, and it had outstanding results. The winning combination (named X1 in his writeup) was to preheat the leather then immerse it in melted stearic acid, followed by bringing the temperature of the combination to 200 ºF for about a minute to heat treat the leather at the same time. [Jason]’s observation was that this method “[B]lew the rest out of the water. Cutting the sample to view the cross section was like carving wood. The leather is very rigid and strong.”

The world may not revolve around leather the way it used to, but there’s still stuff to learn and new things to discover. For example, modern tools can allow for novel takes on old techniques, like using 3D printing to create custom leather embossing jigs.

Decap ICs Without The Peril

May 19, 2019 by Jenny List 13 Comments

There can be few of us who haven’t gazed with fascination upon the work of IC decappers, whether they are showing us classic devices from the early years of mass semiconductor manufacture, or reverse-engineering the latest and greatest. But so often their work appears to require some hardcore scientific equipment or particularly dangerous chemicals. We’ve never thought we might be able to join the fun. [Generic Human] is out to change all that, by decapping chips using commonly available chemicals and easy to apply techniques. In particular, we discover through their work that rosin — the same rosin whose smell you will be familiar with from soldering flux — can be used to dissolve IC packaging.

Of course, ICs that dissolved easily in the face of soldering wouldn’t meet commercial success, so an experiment with flux meets little success. Pure rosin, however, appears to be an effective decapping agent. [Generic Human] shows us a motherboard voltage regulator boiled in the stuff. When the rosin is removed with acetone, there among the debris is the silicon die, reminding us just how tiny these things are. We’re sure you’ll all be anxious to try it for yourselves, now, so take a while to look at the video below showing their CCC Congress talk.

The master of chip decapping is of course [Ken Shirriff], whose work we’ve featured many times. Our editor [Mike Szczys] interviewed him last year, and it’s well worth a look.

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Make An Electroplating Marker, Because Plating Complex Objects Is Hard

May 8, 2019 by Donald Papp 22 Comments

If an object is conductive or has been given a conductive coating, it can be given a metal skin via electroplating. Electroplating is a simple process that is perfectly accessible to anyone in possession of vinegar, salt, a power supply, and some metal such as copper or nickel.

The process might be simple, but as with all such things there are a few gotchas. One of them is this: because electricity follows the path of least resistance, recessed areas of an object may not electroplate well (or at all) no matter how long the object is left immersed. To address this, [Brodie Fairhall] designed a 3D printed electroplating marker. The marker is essentially a more refined version of brush plating, and allows more precision and control than full immersion in an electrolyte bath.

[Brodie] created an excellent video that explains all one needs to start electroplating, and demonstrates using his marker to electroplate complex recessed shapes. Watch him coat a 3D-printed cat pendant in both copper and nickel in the video embedded below. It’s concise, well-edited, and chock full of useful tips.

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Nanoparticles Make Mega Difference For “Unweldable” Aluminum

April 15, 2019 by Kristina Panos 62 Comments

Though much of it is hidden from view, welding is a vital part of society. It’s the glue that holds together the framework of the cars we drive, the buildings we occupy, the appliances we use, and the heavy machinery that keeps us moving forward. Every year, the tireless search continues for stronger and lighter materials to streamline our journey into the future of transportation and space exploration.

Some of these futuristic materials have been around for decades, but the technology needed to weld them lagged behind. A group of researchers at UCLA’s Samueli School of Engineering recently found the key to unlocking the weldability of aluminium alloy 7075, which was developed in the 1940s. By adding titanium carbide nanoparticles to the mix, they were able to create a bond that proved to be stronger than the pieces themselves.

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Anodizing Aluminium In The Land Of The Queen

April 6, 2019 by Lewin Day 11 Comments

Aluminium is a useful material, both for its light weight and resistance to corrosion. This resistance can be improved further with various treatments, one of the more popular being anodizing. This is the process behind the fancy colored metal bling on your cousin’s BMX bike. It’s possible to perform this in the home lab, when taking the appropriate precautions.

[The Recreational Machinist] has been experimenting with anodizing on and off for the last few years, and decided to share their process – as a “what did”, rather than a “how to”. The video is from the perspective of performing this task in the United Kingdom, as the availability of chemicals varies around the world and can affect the viability of various processes involved.

All the relevant techniques are covered, from cathode design to the hardware chosen to give the best results. There’s even discussion of the use of magnetic stirrers to prevent bubble marks, as well as proper cleaning processes to avoid unsightly blemishes from fingerprints or other contaminants. Perhaps the most useful tip provided is that using specific anodizing dyes does give the best results, though it is possible to get by with various types of clothing dye. As always, your mileage may vary.

There’s a big difference between reading theory and seeing the specifics of an actual working process, and [The Recreational Machinist] does a great job of showing off the realities of achieving this at home. We’ve seen it done before, with different chemicals too. Video after the break. Continue reading “Anodizing Aluminium In The Land Of The Queen” →