Metalworking might conjure images of large furnaces powered by coal, wood, or electricity, with molten metal sloshing around and visible in its crucible. But metalworking from home doesn’t need to use anything more fancy than a microwave, at least according to [Denny] a.k.a. [Shake the Future]. He has a number of metalworking tools designed to melt metal using a microwave, and in this video he uses them to make a usable aluminum pencil with a graphite core.
Before getting to the microwave kiln, the pencil mold needs to be prepared. A 3D-printed pencil is first created with the graphite core, and then [Denny] uses a plaster of Paris mixture to create the mold for the pencil. The 3D printed plastic is left inside the mold and placed in the first microwave kiln, which is turned on just enough to melt the plastic out of the mold, leaving behind the graphite core. From there a second kiln goes into the microwave to melt the aluminum.
Once the molten aluminum is ready, it is removed from the kiln and poured in the still-warm pencil mold. This is where [Denny] has another trick up his sleeve. He’s using a household vacuum cleaner to suck the metal into place before it cools, creating a rudimentary but effective vacuum forming machine. The result is a working pencil, at least after he wears down a few razor blades attempting to sharpen the metal pencil. For more information about how [Denny] makes these microwave kilns, take a look at some of his earlier projects.
Hobbyist-grade laser cutters can be a little restrictive as to the types and thicknesses of materials that they can cut. We’re usually talking about CO2 and diode-based machines here, and if you want to cut non-plastic sheets, you’re usually going to be looking towards natural materials such as leather, fabrics, and thin wood.
But what about metals? It’s a common beginner’s question, often asked with a resigned look, that they already know the answer is going to be a hard “no. ” However, YouTuber [Chad] decided to respond to some comments about the possibility of cutting metal sheets using a high-power diode laser, with a simple experiment to actually determine what the limits actually are.
Using an XTool D1 Pro 20W as a testbed, [Chad] tried a variety of materials including mild steel, stainless, aluminium, and brass sheets at a variety of thicknesses. Steel shim sheets in thicknesses from one to eight-thousandths of an inch appeared to be perfectly cuttable, with an appropriate air assist and speed settings, with thicker sheets needing a good few passes. You can definitely see the effect of excess heat in the workpiece, resulting in some discoloration and noticeable warping, but those issues can be mitigated. Copper and aluminium weren’t touched by the beam at all, likely due to the extra reflectivity, but we do have to wonder if appropriate surface treatments could improve matters.
Making knives at home has become a popular hobby, thanks partly to reality TV and the free time and idle hands afforded by lockdowns. Depending on how far you get into the hobby, builds can range from assembling and finishing a kit with pre-forged parts, to actual blacksmithing with a hammer and anvil. But pretty much every build includes steel from a commercial supplier.
Not this one. Rather than buy his metal from the usual sources, [Thoisoi]’s first stop was an iron mine in the Italian Alps, where he picked up a chunk of iron ore — magnetite, to be precise. Smelting one’s own iron from raw ore and alloying it into steel is generally not a backyard project thanks to the high temperatures needed, a problem [Thoisoi] solved with the magic of thermite. The iron oxide and aluminum in the thermite mix react in an exceptionally exothermic manner to generate elemental iron, which under controlled conditions can be captured as a more or less pure ingot, ready for forging.
After a test with commercially obtained iron oxide, [Thoisoi] tried his pulverized magnetite. And thanks to the addition of goodies like graphite, manganese, nickel, silicon, and chromium, he was eventually able to create a sizable lump of 402 stainless steel. He turned the metal over to an actual blacksmith for rough forging; it sure seemed to act like steel on the anvil. The finished knife looks good and performs well, and the blade has the characteristic look of stainless. Not a bad result, and all at the cost of a couple of clay flowerpots.
[FloweringElbow] aka [Bongo] on YouTube is certainly having a go at this, and we reckon he’s onto a winner! This epic flatbed CNC build (video, embedded below) starts with some second hand structural I-beam, with welded-on I-beam legs, DIY cast aluminium side plates and plenty of concrete to give a strong and importantly, heavy structure.
The ideal machine is as rigid as possible, and heavy, to dampen out vibrations caused by high-feed speed cutting, or the forces due to cutting harder materials, so bigger really is better. For construction of the frame, steel is pretty strong, and the mass of the structure gives it additional damping, but triangulation was needed to counteract additional twisting. He stitch-welded the pre-heated frame in inch-long sections to limit the heat transferred into the metal, minimizing the subsequent warpage. [Bongo] used hacky Vibratory stress relief (VSR) constructed from a washing machine motor and eccentric weight, clamped to the frame, with feedback from a mobile phone app to find the resonant frequencies. There are other videos on the channel devoted to that topic of such stress relief techniques.
Precise enough to cut sticky-backed vinyl at half thickness!
When it came time for adding even more mass, a priming coat was made from a mixture of bonding epoxy and sharp grit, intended for non-slip flooring. The concrete mix used Portland cement, pozzolan (Silica fume) polycarboxylate superplasticiser and 1/2″ glass fiber threads. A second mix added crushed stone for additional mass. A neat trick was to make a handheld vibratory compactor from a plate welded onto the end of old drill bit, mounted in an SDS hammer drill.
Once the frame was flipped the right way up (collapsing the overloaded hoist in the process) it was necessary to level the top surface to accept the linear rails. This was done using a super runny, self-leveling epoxy, and checked by flowing water over it. Once the epoxy surfaces were adequately flat and coplanar (and much scraping later) the linear rails were attached, after creating some epoxy shoulders for them to butt up against. End plates to attach the Y axis lead screws, were added by bolting into the frame with a grit-loaded epoxy bond in between.
The gantry design was skipped for this video (but you can see that here) and once mounted a quick test showed the machine was viable. One curious task was making their own cable-chain from ply, on the machine itself, rather than buying something expensive off-the-peg. Why not? Once the machine was working well enough to mill a flat sheet of steel to nice reflective surface, it was used to mount a DIY drag-knife to cut out shapes in some vinyl, so it has the precision. We did like seeing an XBox controller used to manually jog the machine around! So much to see in this build and other related videos, we reckon this channel is one to watch!
We’ve featured CNC builds many a time, there’s a build whatever your needs and budget, but here’s a good starting point to build a machine, just good enough to build the tools you need. If you don’t happen to have a source of structural I-beam to hand, you can do something quite capable with wood, and if you fancy a go at 3D printing a knee mill, we’ve got that covered as well.
While it’s possible to make pizza from scratch at home right down to the dough itself, it’ll be a struggle to replicate the taste and exquisite mouthfeel without a pizza oven. Pizzas cook best at temperatures well over the 260°C/500°F limit on most household ovens while pizza ovens can typically get much hotter than that. Most of us won’t have the resources to put a commercial grade wood-fired brick oven in our homes, but the next best thing is this portable pizza oven from [Andrew W].
The build starts with some sheet metal to form the outer and inner covers for the oven. [Andrew] has found with some testing that a curved shape seems to produce the best results, so the sheet metal goes through rollers to get its shape before being welded together. With the oven’s rough shape completed, he fabricates two different burners. One sits at the back of the oven with its own diffuser to keep the oven as hot as possible and the other sits underneath a cordierite stone to heat from the bottom. Both are fed gas from custom copper plumbing and when it fires up it reaches temperatures hot enough that it can cook a pizza in just a few minutes. With some foldable legs the oven also ends up being fairly portable, and its small size means that it can heat up faster than a conventional oven too.
This is [Andrew]’s third prototype oven, and it seems like he has the recipe perfected. In fact, we featured one of his previous versions almost two years ago and are excited to see the progress he’s made in this build. The only downside to having something like this would be the potential health implications of always being able to make delicious pizzas, but that is a risk we’d be willing to take.
It’s hard to reckon exactly when in history humans became a technological species. Part of that is because the definition of technology is somewhat subjective; if you think making a stick pointy enough to grub roots from the dirt or to poke enough holes in an animal to convince it to let you eat it is technology, then our engineered world goes back a long, long way indeed.
But something about pointy sticks just doesn’t seem transformative enough, in the sense of fundamentally changing a naturally occurring material, to really count as a technological line in the sand. To cross that line, it really seems like the use of metals should be part of the package. Even if that’s the case, our technological history still goes pretty far back. And copper ends up being one of the metals that started it all, about 11,000 years ago, when our ancestors discovered natural deposits of the soft, reddish metal and began learning how to fashion it into the tools and implements that lifted us out of the Stone Age.
Our world literally cannot run without copper, forming as it does not only the electric-motor muscles of civilization, but also the wires and cables that form the power and data grids that stitch us together. Ironically, we are just as dependent on copper now as we were when it was the only metal we could make tools from, and perhaps more so. We’ll take a look at what’s involved in extracting and purifying copper, and see how the methods we today use are not entirely different from those developed over seven millennia ago.
It isn’t an uncommon science fiction trope for our hero to be in a situation where there is no technology. Maybe she’s back in the past or on a faraway planet. The Professor from Gilligan’s Island comes to mind, too. I’d bet the average Hacakday reader could do pretty well in that kind of situation, but there’s one thing that’s often overlooked: materials. Sure, you can build a radio. But can you make wire? Or metal plates for a capacitor? Or a speaker? We tend to overlook how many abstractions we use when we build. Even turning trees into lumber isn’t a totally obvious process.
People are by their very nature always looking for ways to use the things around them. Even 300,000 years ago, people would find rocks and use them as tools. It wasn’t long before they found that some rocks could shape other rocks to form useful shapes like axes. But the age of engineered materials is much younger. Whether clay, metal, glass, or more obviously plastics, these materials are significantly more useful than rocks tied to sticks, but making them in the first place is an engineering story all on its own.
