[Chris Borge] has made (and revised) many of his own tools using a combination of 3D printing and common hardware, and recently decided to try metal casting. Having created his own tapping arm, he tries his hand at aluminum casting to create a much more compact version out of metal. His video (embedded below) really shows off the whole process, and [Chris] freely shares his learning experiences in casting his first metal tool.

The result looks great and is considerably smaller in stature than the 3D-printed version. However, the workflow of casting metal parts is very different. The parts are much stronger, but there is a lot of preparation and post-processing involved.

The key to making good castings is mold preparation. [Chris] uses green sand (a mixture of fine sand and bentonite clay – one source of the latter is ground-up kitty litter) packed tightly around 3D printed parts inside a frame. The packed sand holds its shape while still allowing the original forms to be removed and channels to be cut, creating a two-part mold.

His first-time castings have a rough surface texture, but are perfectly serviceable. After some CNC operations to smooth some faces and drill some holes, the surface imperfections are nothing filing, filler, and paint can’t handle.

To cast molten metal, there really isn’t any way around needing a forge. Or is there? We have seen some enterprising hackers repurpose microwave ovens for this purpose. One can also use a low-temperature alloy like Rose’s Metal, or eschew molten liquid altogether and do cold casting, which uses a mixture of resin and metal powder instead.

The design files for [Chris]’s tapping arm are available from links in the video description, and he also helpfully provides links to videos and resources he found useful. Watch it in the video, embedded just below.

Water cooling was once only the preserve of hardcore casemodders and overclockers. Today, it’s pretty routinely used in all sorts of performance PC builds. However, few are using large artistic castings as radiators like [Mac Pierce] is doing. 

The casting itself was inspired on the concept of the ouroboros, the snake which eats its own tail if one remembers correctly. [Mac] built a wooden form to produce a loop approximately 30″ tall and 24″ wide, before carving it into the classic snake design. The mold was then used to produce a hefty sand cast part which weighed in at just over 30 pounds.

The next problem was to figure out how to create a sealed water channel in the casting to use it as a radiator. This was achieved by machining finned cooling channels into the surface of the snake itself. A polycarbonate face plate was then produced to bolt over this, creating a sealed system. [Mac] also had to work hard to find a supply of aluminum-compatible water cooling fittings to ensure he didn’t run into any issues with galvanic corrosion.

The final product worked, and looked great to boot, even if it took many disassembly cycles to fix all the leaks. The blood-red coolant was a nice touch that really complemented the silvery aluminum. CPU temperatures weren’t as good as with a purpose-built PC radiator, but maxed out at 51 C in a heavy load test—servicable for [Mac]’s uses. The final touch was to simply build the rest of the PC to live inside the ouroboros itself—and the results were stunning.

We’ve featured a few good watercooling builds over the years. If you’ve found your own unique way to keep your hardware cool and happy, don’t hesitate to notify the tipsline!

For all the remarkable improvements we’ve seen in desktop 3D printers, metal printers have tended to stay out of reach for hackers, mostly because they usually rely on precise and expensive laser systems. This makes it all the more refreshing to see [Dan Gelbart]’s demonstration of Rapidia’s cast-to-sinter method, which goes from SLA prints to ceramic or metal models.

The process began by printing the model in resin, scaled up by 19% to account for shrinkage. [Dan] then used the resin print to make a mold out of silicone rubber, after first painting the model to keep chemicals from the resin from inhibiting the silicone’s polymerization. Once the silicone had set, he cut the original model out of the mold and prepared the mold for pouring. He made a slurry out of metal powder and a water-based binder and poured this into the mold, then froze the mold and its contents at -40 ℃. The resulting mixture of metal powder and ice forms a composite much stronger than pure ice, from which [Dan] was able to forcefully peel back the silicone mold without damaging the part. Next, the still-frozen part was freeze-dried for twenty hours, then finally treated in a vacuum sintering oven for twelve hours to make the final part. The video below the break shows the process.

A significant advantage of this method is that it can produce parts with much higher resolution and better surface finish than other methods. The silicone mold is precise enough that the final print’s quality is mostly determined by the fineness of the metal powder used, and it’s easy to reach micron-scale resolution. The most expensive part of the process is the vacuum sintering furnace, but [Dan] notes that if you only want ceramic and not metal parts, a much cheaper ceramic sintering oven will work better.

We’ve seen sintering-based metal printers a few times before, as well a few more esoteric methods. We’ve also covered a few of [Dan]’s previous videos on mechanical prototyping methods and building a precision CNC lathe.

Thanks to [Eric R Mockler] for the tip!

Perfectly clear ice spheres are nifty but can be a bit tricky to make without an apparatus. [Seth Robinson] crafted a copper ice press to make his own.

Copper is well-known for its thermal conductivity, making it a perfect material for building a press to melt ice into a given shape. Like many projects, a combination of techniques yields the best result, and in this case we get to see 3d printing, sand casting, lost PLA casting, lathe turning, milling, and even some good old-fashioned sanding.

The most tedious part of the process appears to be dip coating of ceramic for the lost PLA mold, but the finished result is certainly worth it. That’s not to say that any of the process looks easy if you are a metal working novice. Taking over a week to slowly build up the layers feels a bit excruciating, especially compared to 3D printing the original plastic piece. If you’re ever feeling discouraged watching someone else’s awesome projects, you might want to stick around to the end when [Robinson] shows us his first ever casting. We’d say his skill has improved immensely over time.

If you’re looking for something else to do with casting copper alloys, be sure to checkout this bronze river table or [Robinson’s] copper levitation sphere.

Thanks to [DjBiohazard] for the tip!

River tables are something we’ve heard decried as a passé, but we’re still seeing some interesting variations on the technique. Take this example done with bronze instead of epoxy.

Starting with two beautiful slabs of walnut, [Burls Art] decided that instead of cutting them up to make guitars he would turn his attention to a river table to keep them more intact. Given the price of copper and difficulty in casting it, he decided to trim the live edges to make a more narrow “river” to work with for the project.

Since molten copper is quite toasty and wood likes to catch on fire, he wisely did a rough finish of the table before making silicone plugs of the voids instead of pouring metal directly. The silicone plugs were then used to make sand casting molds, and a series of casting trials moving from copper to bronze finally yielded usable pieces for the table. In case that all seems too simple, there were then several days of milling and sanding to get the bronze and walnut level and smooth with each other. The amount of attention to detail and plain old elbow grease in this project is impressive.

We’ve seen some other interesting mix-ups of the live edge and epoxy formula like a seascape night light or this river table with embedded neon. And if you’re looking to get into casting, why not start small in the microwave?

A couple of weeks back, we covered an interesting method for prototyping PCBs using a modified CNC mill to 3D print solder onto a blank FR4 substrate. The video showing this process generated a lot of interest and no fewer than 20 tips to the Hackaday tips line, which continued to come in dribs and drabs this week. In a world where low-cost, fast-turn PCB fabs exist, the amount of effort that went into this method makes little sense, and readers certainly made that known in the comments section. Given that the blokes who pulled this off are gearheads with no hobby electronics background, it kind of made their approach a little more understandable, but it still left a ton of practical questions about how they pulled it off. And now a new video from the aptly named Bad Obsession Motorsports attempts to explain what went on behind the scenes.

To be quite honest, although the amount of work they did to make these boards was impressive, especially the part where they got someone to create a custom roll of fluxless tin-silver solder, we have to admit to being a little let down by the explanation. The mechanical bits, where they temporarily modified the CNC mill with what amounts to a 3D printer extruder and hot end to melt and dispense the solder, wasn’t really the question we wanted answered. We were far more interested in the details of getting the solder traces to stick to the board as they were dispensed and how the board acted when components were soldered into the rivets used as vias. Sadly, those details were left unaddressed, so unless they decide to make yet another video, we suppose we’ll just have to learn to live with the mystery.

What do mushrooms have to do with data security? Until this week, we’d have thought the two were completely unrelated, but then we spotted this fantastic article on “Computers Are Bad” that spins the tale of Iron Mountain, which people in the USA might recognize as a large firm that offers all kinds of data security products, from document shredding to secure offsite storage and data backups. We always assumed the “Iron Mountain” thing was simply marketing, but the company did start in an abandoned iron mine in upstate New York, where during the early years of the Cold War, it was called “Iron Mountain Atomic Storage” and marketed document security to companies looking for business continuity in the face of atomic annihilation. As Cold War fears ebbed, the company gradually rebranded itself into the information management entity we know today. But what about the mushrooms? We won’t ruin the surprise, but suffice it to say that IT people aren’t the only ones that are fed shit and kept in the dark.

Do you like thick traces? We sure do, at least when it comes to high-current PCBs. We’ve seen a few boards with really impressive traces and even had a Hack Chat about the topic, so it was nice to see Mark Hughes’ article on design considerations for heavy copper boards. The conventional wisdom with high-current applications seems to be “the more copper, the better,” but Mark explains why that’s not always the case and how trace thickness and trace spacing both need to be considered for high-current applications. It’s pretty cool stuff that we hobbyists don’t usually have to deal with, but it’s good to see how it’s done.

We imagine that there aren’t too many people out there with fond memories of Visual Basic, but back when it first came out in the early 1990s, the idea that you could actually make a Windows PC do Windows things without having to learn anything more than what you already knew from high school computer class was pretty revolutionary. By all lights, it was an awful language, but it was enabling for many of us, so much so that some of us leveraged it into successful careers. Visual Basic 6 was pretty much the end of the line for the classic version of the language, before it got absorbed into the whole .NET thing. If you miss that 2008 feel, here’s a VB6 virtual machine to help you recapture the glory days.

And finally, in this week’s “Factory Tour” segment we have a look inside a Japanese aluminum factory. The video mostly features extrusion, a process we’ve written about before, as well as casting. All of it is fascinating stuff, but what really got us was the glow of the molten aluminum, which we’d never really seen before. We’re used to the incandescent glow of molten iron or even brass and copper, but molten aluminum has always just looked like — well, liquid metal. We assumed that was thanks to its relatively low melting point, but apparently, you really need to get aluminum ripping hot for casting processes. Enjoy.

Most of us have made paper airplanes at one time or another, but rather than stopping at folded paper, [VirgileC] graduated to 3D printing them out of PLA. Then the obvious question is: can you cast one in cement? The answer is yes, you can, but note that the question was not: can a cement plane fly? The answer to that is no, it can’t.

Of course, you could use this to model things other than non-flying airplanes. The key is using alginate, a natural polymer derived from brown seaweed, to form the mold. The first step was to suspend the PLA model in a flowerpot with the holes blocked. Next, the flowerpot gets filled with alginate.

After a bit, you can remove the PLA from the molding material by cutting it and then reinserting it into the flower pot. However, you don’t want it to dry out completely as it tends to deform. With some vibration, you can fill the entire cavity with cement.

The next day, it was possible to destroy the alginate mold and recover the cement object inside. However, the cement will still be somewhat wet, so you’ll want to let the part dry further.

Usually, we see people print the mold directly using flexible filament. If you don’t like airplanes, maybe that’s a sign.