Etching Aluminium Coins, Just For Fun

[MakeFailRepeat] was heading to MakerCentral in Birmingham, an event to which many makers were bringing coins to swap and trade. Wanting to get in on the action, he decided to etch some coins of his very own.

Etching aluminium is a simple process, readily accessible to the average maker. [MakeFailRepeat] started with an aluminium bar, and applied sticky-backed vinyl to the surface. This was then lasercut with the coin artwork, and the pieces removed to leave a negative space design for etching. With the resist layer in place, the aluminium was placed in a bath of salt water, and attached to the positive electrode of a DC supply or battery. With the negative electrode attached to a bolt, the aluminium is left to etch, with care taken to avoid over-etching. As a final finishing step, the coins were then placed in a cobbled-together rock tumbler, using scrap 3D printer filament as media.

The coins are a little rough around the edges, but we think they’re great for a first attempt. There’s plenty of different ways to etch; toner transfer is a particularly popular method. Video after the break.

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Nanoparticles Make Mega Difference For “Unweldable” Aluminum

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

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”

Grawler: Painless Cleaning For Glass Roofs

Part of [Gelstronic]’s house has a glass roof. While he enjoys the natural light and warmth, he doesn’t like getting up on a ladder to clean it every time a bird makes a deposit or the rainwater stains build up. He’s tried to make a cleaning robot in the past, but the 25% slope of the roof complicates things a bit. Now, with the addition of stepper motors and grippy tank treads, [Gelstronic] can tell this version of GRawler exactly how far to go, or to stay in one place to clean a spot that’s extra dirty.

GRawler is designed to clean on its way up the roof, and squeegee on the way back down. It’s driven by an Arduino Pro Micro and built from lightweight aluminium and many parts printed in PLA. GRawler also uses commonly-available things, which is always a bonus: the brush is the kind used to clean behind appliances, and the squeegee blade is from a truck-sized wiper. [Gelstronic] can control GRawler’s motors, the brush’s spin, and raise/lower the wiper blade over Bluetooth using an app called Joystick BT Commander. Squeak past the break to see it in action.

As far as we can tell, [Gelstronic] will still have to break out the ladder to place GRawler and move him between panels. Maybe the next version could be tethered, like Scrobby the solar panel-cleaning robot.

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This Vapour Deposition Chamber Isn’t Vapourware

If you are an astronomer with an optical reflecting telescope, the quality of your mirror is one of your most significant concerns. Large observatories will therefore often have on-site vapour deposition plants to revitalise their reflectors by depositing a fresh layer of aluminium upon them. You might think that such a device would be the preserve only of such well-funded sites, but perhaps [Michael Koch]’s work will prove you wrong. He’s created his own vapour deposition system (Google Translate link of the German original) from scratch, and while it might be smaller than the institutional equivalents it is no less effective in its task.

At the heart of it is a stainless steel vacuum vessel with a two stage vacuum pump system to evacuate it. The mirror to be silvered is suspended in the vessel, and a piece of aluminium is suspended over a coil of tungsten wire that his electrically heated to melt it. The molten aluminium is described as “wetting” the tungsten wire in the same manner as we’ll be used to solder working on copper, but in the vacuum it vaporizes and deposits itself upon the mirror. Such a simple description glosses over the impressive work that went into it.

This is a long-running project that isn’t entirely new, but very much worth a look if only for its introduction to this fascinating field. If you are new to vacuum work, how about looking at a Superconference presentation introducing vacuum technology?

Thanks [Paul Bauer] for the tip.

Lathe Turns The Corner, Makes A Cube

[Tim] was tired of using his lathe to turn round things. He decided to make a gaming die—something that’s iconically square—out of cylindrical scrap. As it turns out, this is possible to do on a lathe with a three jaw chuck. [Tim] discovered that the bevel on the jaws will hold a cylindrical puck of scrap sideways while he squares off the round sides into faces.

Turning a cube on a lathe looks pretty fiddly, so we applaud [Tim]’s lovely handiwork even more. As you’ll see in the video down below, things were going gangbusters until he went to make the last facing cut. Maybe the tool wasn’t lined up just so, or something was off in the chucking, but the first pass made a bit of a gouge in the stock. Looks like it was easy enough to fix, though. After four 90° turns and facing cuts, he had a nice looking rough cube to work with.

This is a regulation-sized die, so the next step was to trim it down to 16mm³. Then it was time to sand, polish, and add the dots. To lay them out, [Tim] sprayed the cube with layout fluid and scribed unique line patterns on each face. Then he drilled the indentations and filled them in with aluminium black.

Most of the dice we see are electronic, like this extremely random pair and these PIC-driven LED dice. We’d like to see [Tim] make a second D6 so he has a pair. And then make a D20. Please?

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Robotic Arm Rivals Industrial Counterparts

We’ve seen industrial robotic arms in real life. We’ve seen them in classrooms and factories. Before today, we’ve never mistaken a homemade robotic arm for one of the price-of-a-new-home robotic arms. Today, [Chris Annin] made us look twice when we watched the video of his six-axis robotic arm. Most of the DIY arms have a personal flare from their creator so we have to assume [Chris Annin] is either a robot himself or he intended to build a very clean-looking arm when he started.

He puts it through its paces in the video, available after the break, by starting with some stretches, weight-lifting, then following it up and a game of Jenga. After a hard day, we see the arm helping in the kitchen and even cracking open a cold one. At the ten-minute mark, [Chris Annin] walks us through the major components and talks about where to find many, many more details about the arm.

Many of the robotic arms on Hackaday are here by virtue of resourcefulness, creativity or unusual implementation but this one is here because of its similarity to the big boys.

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