This Scratch-Built X-Ray Tube Really Shines

September 24, 2022 by Dan Maloney 25 Comments

On no planet is making your own X-ray tube a good idea. But that doesn’t mean we’re not going to talk about it, because it’s pretty darn cool.

And when we say making an X-ray tube, we mean it — [atominik] worked from raw materials, like glass test tubes, tungsten welding electrodes, and bits of scrap metal, to make this dangerously delightful tube. His tool setup was minimalistic as well– where we might expect to see a glassblower’s lathe like the ones used by [Dalibor Farny] to make his custom Nixie tubes, [atominik] only had a small oxy-propane hand torch to work with. The only other specialized tools, besides the obvious vacuum pump, was a homebrew spot welder, which was used to bond metal components to the tungsten wires used for the glass-to-metal seals.

Although [atominik] made several versions, the best tube is a hot cathode design, with a thoriated tungsten cathode inside a copper focusing cup. Across from that is the anode, a copper slug target with an angled face to direct the X-rays perpendicular to the long axis of the tube. He also included a titanium electrode to create a getter to scavenge oxygen and nitrogen and improve the vacuum inside the tube. All in all, it looks pretty similar to a commercial dental X-ray tube.

The demonstration in the video below is both convincing and terrifying. He doesn’t mention the voltage he’s using across the anode, but from the cracking sound we’d guess somewhere around 25- to 30 kilovolts. The tube really gets his Geiger counter clicking.

Here’s hoping [atominik] is taking the proper precautions during these experiments, and that you do too if you decide to replicate this. You’ll also probably want to check out our look at the engineering inside commercial medical X-ray tubes.

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Just How Good Is A Tape Measure Antenna Anyway?

August 14, 2022 by Dan Maloney 36 Comments

Amateur radio operators have played a longstanding game of “Will It Antenna?” If there’s something even marginally conductive and remotely resonant, a ham has probably tried to make an antenna out of it. Some of these expedient antennas actually turn out to be surprisingly effective, but as we can see from this in-depth analysis of the characteristics of tape measure antennas, a lot of that is probably down to luck.

At first glance, tape measure antennas seem to have a lot going for them (just for clarification, most tape measure antennas use only the spring steel blade of a tape measure, not the case or retraction mechanism — although we have seen that done.) Tape measures can be rolled up or folded down for storage, and they’ll spring back out when released to form a stiff, mostly self-supporting structure.

But [fvfilippetti] suspected that tape measures might have some electrical drawbacks, thanks to the skin effect. That’s the tendency for current to flow on the outside of a conductor, which at lower frequencies on conductors with a round cross-section turns out to be not a huge problem. But in a thin, rectangular conductor, a little finite element method magnetics (FEMM) analysis revealed that most of the current is carried in very small areas, resulting in high electrical resistance — an order of magnitude greater than a round conductor. Add in the high permittivity of the carbon steel material of the blade, and you end up something more like what [fvfilippetti] calls “a tape measure dummy load.

One possible solution: stripping the paint off the blade and copper plating it. It’s not clear if this was tried; we’d think it would be difficult to accomplish, but not impossible — and surely worth a try.

Brass Plaque Honors Brother

August 3, 2022 by Brian McEvoy 10 Comments

Brass plaques are eye-catching because no one makes them on a whim. They are more costly than wood or plastic, and processing them is proportionally difficult. [Becky Stern] picked the medium to honor her brother, who enjoyed coffee, motorcycles, and making things by hand. She made some playing card-sized pieces to adorn his favorite brand of hot bean juice and a large one to hang at his memorial site.

The primary components are a vertical salt water bath, DC power supply, metal to etch, scrap steel approximately the same size, and a water agitator, which in this case is an air pump and diffuser stone. You could stir manually for two hours and binge your shows but trust us and take the easy route. The video doesn’t explicitly call for flexible wires, but [Becky] wisely selected some high-strand hook-up leads, which will cause fewer headaches as stiff copper has a mind of its own, and you don’t want the two sides colliding.

There are a couple of ways to transfer an insulating mask to metal, and we see the ole’ magazine paper method fail in the video, but cutting vinyl works a treat. You may prefer lasers or resin printers, and that’s all right too. Once your mask is sorted, connect the positive lead to the brass and the negative to your steel. Now, it’s into the agitated salt water bath, apply direct current, and allow electricity to immortalize your design.

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Dead Solar Panels Are The Hottest New Recyclables

July 19, 2022 by Lewin Day 99 Comments

When it comes to renewable energy, there are many great sources. Whether it’s solar, wind, or something else, though, we need a lot of it. Factories around the globe are rising to the challenge to provide what we need.

We can build plenty of new solar panels, of course, but we need to think about what happens when they reach end of life. As it turns out, with so much solar now out in the field, a major new recycling industry may be just around the corner.

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PS5 Goes On Slim-Fast

June 20, 2022 by Matthew Carlson 28 Comments

For the past few decades, most console makers have first come out with a large flagship model, and then a few years later, released a smaller, more compact slim edition. Not content to wait for it, [Matt] at DIY Perks made his own PS5 Slim, and the results are awe-inspiring.

Generally, slim editions are made by lowering the TDP of the chip under the hood. A lower power draw means less cooling is needed, a smaller power supply can be used, and a design that is overall easier to manage. Unfortunately, [Matt] had none of these benefits and instead had to contend with the full 180 W that the AMD CPU inside the PlayStation can draw.

Taking apart the console left him with the main board that was quite thick as it had heat pipes on both sides. His first thought was water cooling as it can rapidly move the heat needed, but even with right-angle fittings, it didn’t fit within the ambitious thickness goal he had set for himself of less than 2 cm (about 3/4″). To do that, [Matt] had to fabricate a copper water block from three sheets of copper. The first one connects to the motherboard via standoffs and has cut-outs for various connectors and parts. The middle layer has a channel through which water can flow, and the last layer seals it together.

With the three layers together, he soldered them in a toaster oven repurposed as a reflow oven. Cleverly, he used silicone grease to prevent solder from getting into areas he didn’t want, like the fins in the CPU block. Luckily, the grease dissolved in alcohol, and after flushing the chamber, he had a solid copper, water-tight, custom loop. However, on his road to glory, [Matt] ran into a snag. He accidentally covered the intake vent on the radiator, and the PS5 overheated, killing it. With a fried mainboard and a project almost on the cusp of completion, he resorted to using the PS5 he had received for B-roll.

Last-minute motherboard swap aside, the final project is gorgeous. The polished exterior and sheer thinness of it are striking. [Matt] has already disguised his PS5 before and after this, we’re not quite sure where he could possibly take it next. But we’re excited to find out.

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Turning Scrap Copper Into Beautiful Copper Acetate Crystals

April 20, 2022 by Dan Maloney 37 Comments

Crystals, at least those hawked by new-age practitioners for their healing or restorative powers, will probably get a well-deserved eye roll from most of the folks around here. That said, there’s no denying that crystals do hold sway over us with the almost magical power of their beauty, as with these home-grown copper acetate crystals.

The recipe for these lovely giant crystals that [Chase Lean] shares is almost too simple — just scrap copper, vinegar, and a bit of hydrogen peroxide — and just the over-the-counter strength versions of those last two. The process begins with making a saturated solution of copper acetate by dissolving the scrap copper bits in the vinegar and peroxide for a couple of days. The solution is concentrated by evaporation until copper acetate crystals start to form. Suspend a seed crystal in the saturated solution, and patience will eventually reward you with a huge, shiny blue-black crystal. [Chase] also shares tips for growing crystal clusters, which have a beauty of their own, as do dehydrated copper acetate crystals, with their milky bluish appearance.

Is there any use for these crystals? Probably not, other than their beauty and the whole coolness factor of watching nature buck its own “no straight lines” rule. And you’ll no doubt remember [Chase]’s Zelda-esque potassium ferrioxalate crystals, or even when he turned common table salt into perfect crystal cubes.

Copper Modding Helps Cool A Toasty GPU

March 24, 2022 by Lewin Day 35 Comments

[DandyWorks] had an NVIDIA RTX 3070 Ti GPU, and found it was running incredibly hot, with the card’s memory hitting temperatures of 110 °C. He decided to try “copper modding” to solve the problem, and made some impressive improvements along the way.

Copper modding is where small copper shims are used to connect hot chips on the GPU to the heatsink more effectively than the standard thermal pads used by the manufacturer. Copper has much better thermal conductivity than thermal pads, and thus can help improve cooling of components when used in this fashion.

With the GPU carefully disassembled, [DandyWorks] notes the design uses a sub-heatsink specifically for the memory chips. He then sets about removing the thermal pads from the chips with isopropyl alcohol to help. They’re replaced with copper shims of a precise thickness, with a thin layer of thermal paste to ensure good heat flow. [DandyWorks] also shields all surrounding parts of the board with Kapton tape to avoid shorts if the copper shims happen to shift at any point.

Running the same hashing operation, the GPU now operates with its memory at a much cooler temperature of just 64 °C. [DandyWorks] ran the test for hours and temperatures didn’t climb beyond there. It’s evidence that the copper shims do a far better job of conducting the heat out of the memory chips versus the stock thermal pad setup.

We’ve seen some other interesting mods in this vein before, such as CPU die lapping for better thermal performance. Video after the break.

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