3D-Printed Tooling Enables DIY Electrochemical Machining

When it comes to turning a raw block of metal into a useful part, most processes are pretty dramatic. Sharp and tough tools are slammed into raw stock to remove tiny bits at a time, releasing the part trapped within. It doesn’t always have to be quite so violent though, as these experiments in electrochemical machining suggest.

Electrochemical machining, or ECM, is not to be confused with electrical discharge machining, or EDM. While similar, ECM is a much tamer process. Where EDM relies on a powerful electric arc between the tool and the work to erode material in a dielectric fluid, ECM is much more like electrolysis in reverse. In ECM, a workpiece and custom tool are placed in an electrolyte bath and wired to a power source; the workpiece is the anode while the tool is the cathode, and the flow of charged electrolyte through the tool ionizes the workpiece, slowly eroding it.

The trick — and expense — of ECM is generally in making the tooling, which can be extremely complicated. For his experiments, [Amos] took the shortcut of 3D-printing his tool — he chose [Suzanne] the Blender monkey — and then copper plating it, to make it conductive. Attached to the remains of a RepRap for Z-axis control and kitted out with tanks and pumps to keep the electrolyte flowing, the rig worked surprisingly well, leaving a recognizably simian faceprint on a block of steel.

[Amos] admits the setup is far from optimized; the loop controlling the distance between workpiece and tool isn’t closed yet, for instance. Still, for initial experiments, the results are very encouraging, and we like the idea of 3D-printing tools for this process. Given his previous success straightening his own teeth or 3D-printing glass, we expect he’ll get this fully sorted soon enough.

DIY Electrolysis Tank: Removing Rust While You Sleep

Anyone who’s done a bit of metalworking will know how quickly your stockpile will pick up a coating of rust with even just a bit of humidity. While welding requires only a bit of wire brushing at the joint areas, cleaning a large frame for paint is a completely different story. The projects [Make it Extreme] gets himself into tend to involve a lot of steel, so he built his own electrolysis tank for rust removal.

Electrolytic rust removal involves placing the piece of steel to be cleaned into an alkaline electrolyte solution (water and washing soda) with a sacrificial steel anode and connecting a low voltage DC supply over the two pieces. [Make it Extreme] started with an old plastic container, around which he built a very neat trolley frame. He obviously put some thought into how the tank will be cleaned, since it can be removed by unscrewing six bolts and removing the top part of the frame.

The high current, low voltage power supply that is required for the process was built using an old microwave transformer. The secondary coil is removed and replaced with coil of thick insulated wire, to convert it into a step down transformer. After the rewinding the transformer outputs about 13 VAC, which is then run through beefy bridge rectifier modules to get a DC current. A custom machined copper bolt terminal is mounted through the side of the tank to attach the sacrificial anode plate to the positive lead of the power supply, while the negative lead is clamped to the rusty steel to be cleaned.

[Make it Extreme]’s projects never get old, with everything from rideable tank tracks to rotary electric guns. Check out the video after the break to see the build and an impressive demo. Continue reading “DIY Electrolysis Tank: Removing Rust While You Sleep”

Extreme Refurbishing: Amiga Edition

The last Amiga personal computer rolled off the assembly line in 1996, well over 20 years ago. Of course, they had their real heyday in the late 80s, so obviously if you have any around now they’ll be in need of a little bit of attention. [Drygol] recently received what looks like a pallet of old Amiga parts and set about building this special one: The Vampiric Amiga A500.

The foundation of this project was a plain A500 with quite a bit of damage. Corrosion and rust abounded inside the case, as well as at least one animal. To start the refurbishment, the first step was to remove the rust from the case and shields by an electrochemical method. From there, he turned his attention to the motherboard and removed all of the chips and started cleaning. Some of the connectors had to be desoldered and bathed in phosphoric acid to remove rust and corrosion, and once everything was put back together it looks almost brand new.

Of course, some other repairs had to be made to the keyboard and [Drygol] put a unique paint job on the exterior of this build (and gave it a name to match), but it’s a perfect working Amiga with original hardware, ready to go for any retrocomputing enthusiast. He’s no stranger around here, either; he did another extreme restoration of an Atari 800 XL about a year ago.

Hydrogen Powered Nerf Blaster Is Dangerously Awesome

Nerf blasters have been around for decades now, exciting children and concerning parents alike. Most are powered by springs or compressed air, and are the ideal holiday toy for putting delicate family heirlooms at risk. Not content to settle for the usual foam-flinging sidearm, [Peter Sripol] decided to take things up a notch.

The build starts with a MEGA CYCLONESHOCK blaster, which uses the larger red NERF darts as ammunition. Water tanks are rigged to the outside, fitted with stainless steel electrodes. The original spring & plunger firing  assembly is then removed, to make room for a firing chamber made out of copper pipe. A small taser-like device is used as an igniter. When the charging switch is pressed, current is passed through the electrodes in the water, which splits the water into hydrogen and oxygen gas. This is then passed to the firing chamber, where it can be ignited by the taser module, activated by the trigger.

Despite some issues with the blaster occasionally destroying darts due to what appears to be overpressure, it is capable of higher shot velocities than the stock blaster. For all its complexity, performance is somewhat hit and miss, but the cool factor of a handheld hydrogen bubbler is hard to ignore. [Peter] does note however that the combination of explosive gases and dangerous catalyst chemicals make this one build that’s probably best left to adults.

If this NERF hack isn’t dangerous enough, you might prefer these Taser darts instead. Video after the break.

[Thanks to Baldpower for the tip!]

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Electrolysis Tank Removes Rust

If you have something rusty, you can get a wire brush and a lot of elbow grease. Or you can let electricity do the work for you in an electrolysis tank. [Miller’s Planet] shows you how to build such a tank, but even better, he explains why it works in a very detailed way.

The tank uses a sodium carbonate electrolyte — just water and washing powder. In the reaction, free electrons from the electrolyte displace the oxygen from the rusted metal piece. A glass container, a steel rod, and a power supply make up the rest.

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[Cody] Builds A Chlorine Machine

In his continuing bid to have his YouTube channel demonetized, [Cody] has decided to share how he makes chlorine gas in his lab. Because nothing could go wrong with something that uses five pounds of liquid mercury and electricity to make chlorine, hydrogen, and lye.

We’ll be the first to admit that we don’t fully understand how the Chlorine Machine works. The electrochemistry end of it is pretty straightforward – it uses electrolysis to liberate the chlorine from a brine solution. One side of the electrochemical cell generates chlorine, and one side gives off hydrogen as a byproduct. We even get the purpose of the mercury cathode, which captures the sodium metal as an amalgam. What baffles us is how [Cody] is pumping the five pounds of mercury between the two halves of the cell. Moving such a dense liquid would seem challenging, and after toying with more traditional approaches like a peristaltic pump, [Cody] leveraged the conductivity of mercury to pump it using a couple of neodymium magnets. He doesn’t really explain the idea other than describing it as a “rail-gun for mercury,” but it appears to work well enough to gently circulate the mercury. Check out the video below for the build, which was able to produce enough chlorine to dissolve gold and to bleach cloth.

We need to offer the usual warnings about how playing with corrosive, reactive, and toxic materials is probably not for everyone. His past videos, from turning urine into gunpowder to mining platinum from the side of the road, show that [Cody] is clearly very knowledgeable in the ways of chemistry and that he takes to proper precautions. So if you’ve got a jug of mercury and you want to try this out, just be careful.

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Hair Today, Gone Tomorrow, Via Electrolysis

We think of electrolysis as a way to split things like water into oxygen and hydrogen using electricity, but it has a second meaning which is to remove hair using electricity. An electrologist inserts very thin needles into each hair follicle and uses a burst of electricity to permanently remove the hair. [Abbxrdy] didn’t want to buy a cheap unit because they don’t work well and didn’t want to spend on a professional setup, so designing and building ensued.

You’ll have to read through the comments to find some build details and the schematic. The device uses commercial electrolysis needles and a DE-9 connector socket as a holder. The device can supply 6 to 22V at up to 2mA. A timer can restrict the pulse to 5 seconds or less.

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