Full-Color Looks Great On 3D Printed Sliding Puzzles

September 16, 2026 by Donald Papp 4 Comments

[Angus] of [Maker’s Muse] shows off both a parametric, print-in-place sliding puzzle design he created, and the results of UV printing full-color designs on the same. The results look beautiful, and there was a whole lot of trial and error involved in the process.

The design includes a pop-out tile, which can be re-inserted to a finished puzzle.

Creating a good print-in-place sliding puzzle depends a lot on tolerances. Today’s 3D printers are much more capable in this regard than they were ten or so years ago, but getting the right feel to the pieces was still a long learning process. It’s not at all easy to get all the different characteristics in the right balance. On one hand, if the pieces are too tight they won’t slide easily. But if they are too loose, the puzzle can bind because the pieces have too much play. It may also flex enough to pop apart. And of course, the shape of the pieces and their mating surfaces are constrained to angles and shapes that 3D print reliably. [Angus] persevered and succeeded, and shows off everything from cute 3 x 3 units to a massive scaled-up 11 x 11 puzzle, printed on his Prusa XL.

Getting the color onto the print is the work of a desktop UV ink printer, the same model our own Tom Nardi had a hands-on look at last year. [Angus] shows how printing a single color image onto the puzzle is pretty easy and looks great, but what’s even better is a textured relief image with some real tactile depth to it. Expect a lot more work to do for that, because thick layers of ink gum the puzzle up with overspray unless one avoids printing over the gaps in the tiles.

Watch both the puzzles and the color printing in action in his video, embedded just below.

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How To Fold Curved Lines In Metal Without Fancy Tools

September 11, 2026 by Donald Papp 19 Comments

Folding a sheet of metal in a straight line is one thing, but how does one fold multiple curved lines into a sheet of aluminum without fancy machines? [John] demonstrates how to do exactly that with little more than hand tools and a fair bit of patience. The secret is drilling a lot of small holes along each fold line.

First, a bit of background. [John] wanted to fabricate a curved piece of aluminum as cover that would match the sleek aerodynamic lines of a Belly Tank Lakester. The trick is that there isn’t a single straight line to be found, and the fold lines are all curves. How can one do such folding with only hand tools?

[John] found that fabrication was possible by drilling small holes all along each fold line, then carefully bending as needed. The line of holes weakens the metal, acting like a score line, and allow the required curves to be made cleanly. There’s some finishing work and straightening involved, but the hard part of making the actual folds is taken care of.

One method that didn’t work was cutting a shallow groove in the metal to create something like a pre-scored fold line. [John] tried this and found that while the metal does indeed fold along the weakened line, the aluminum tends to crack in the process. When making a line of holes instead, the metal between each hole bends nicely.

This technique does mean the finished part ends up with small perforations along each fold, but the part is mounted on the bottom of the car and [John] says that he’d have to look quite closely to notice. A little polishing goes a long way, too.

We have covered many ways to bend sheet metal and while machinery exists to do it exceedingly well, great results can be had with little more than simple tools and some patience.

Watch [John] go through the process in the video embedded below, or skip to 7:55 if you just want to see the end result.

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Corners Lifting On 3D Prints? Guide Gives Prevention Tips

September 3, 2026 by Donald Papp 17 Comments

Large prints have a risk of warping, by which we mean corners can lift off the print bed as the object sort of curls inward on itself. It’s not always due to poor filament quality or an unclean build plate. Sound like something you’ve dealt with? Check out this handy roundup to understand why it happens, and learn ways to prevent it.

A big flat area with sharp corners is susceptible to warping. Breaking the footprint into a grid pattern helps distribute stresses instead of concentrating them at the corners.

The reason some objects have trouble while others don’t is physics. Deposited plastic shrinks ever so slightly as it cools, and some shapes — like wide, flat surfaces with sharp corners — are worse for this than others. This sort of problem is what the guide addresses with a number of techniques.

Some are simple, like turning on brims which increases an object’s footprint. This increased surface area offers more adhesion, but also increases heat transfer from the print bed into the model, slowing the cooling process. Thinner walls and an altered infill pattern is another option. Other techniques are more complex.

The most effective methods involve modifying the model itself to reduce or eliminate stress points. One such method is to break the model’s footprint into multiple zones with a shallow grid. Instead of one big flat bottom, the object has multiple smaller ones. Because big flat areas are more susceptible to warping than small ones, turning the bottom into a grid pattern helps spread those stresses out and prevent lifting.

If you design your own models, you’ll find several design tips worth keeping in mind. It’s always smart to practice good DFM (Design For Manufacturability) which means taking 3D printer strengths and weaknesses into account when designing an object. In this case, it can help prevent print failures. Good DFM can also make parts much, much stronger just by designing in the right features.

Straight Talk On 3D Printing Footwear At Home

August 24, 2026 by Donald Papp 14 Comments

Printed footwear is an intriguing idea, but as far as projects go it is somewhat more complex than it first appears. This guide to 3D printing your own clogs not only provides a solid process, but also acts as a list of the challenges and pitfalls involved. After all, a piece of footwear is actually a fairly large object. Failed prints can be costly and time-consuming, so a guide like this is a valuable resource.

First of all, a 3D printer that can handle multi-material printing is called for. The footwear itself will be printed in TPU 90A as a sweet spot for hardness, but the print will require supports and those supports will need to peel away cleanly. The solution is a shoe printed in TPU with a rigid support structure of PLA. Using two different materials in the same print with anything remotely resembling efficiency calls for either a dual-nozzle print head, or a multi-toolhead printer.

3D printing one’s own clogs can be rewarding, if not necessarily cost-effective.

Here we want to take a moment and say that while the guide itself suggests PETG is also a suitable support structure, we suspect this might only be true for the exact filament formulations used in the guide. The safer approach is to use PLA. Why? As we’ve seen in other tests, PETG has been observed to stick extremely well to flex filaments in general, whereas PLA doesn’t really want to stick to anything other than PLA. The exact formulations of TPU and PETG used in the guide might be compatible with one another, but in general we recommend sticking to PLA as a rigid support for flexible filament.

Assuming a capable printer and suitable materials are nailed down, one also needs to worry about keeping the TPU dry. It is very sensitive to moisture, which directly affects print quality. You’ll also need to dial in the settings — a gyroid-patterned infill of 15% provides the right amount of “squish”, which is most effectively fine-tuned by changing the infill pattern rather than the density.

Is it worth the time and effort and filament cost to print one’s own pair of slip-ons versus simply buying a pair of Crocs®? Maybe not, but it can still be rewarding and this guide will help minimize any failed prints in the process. And if you do get a nice print but the TPU is sticking a little too well to the build plate, reach for the isopropyl alcohol.

Turning Glass Into A Touch-Sensitive Button

July 31, 2026 by Maya Posch 4 Comments

Although generally glass isn’t associated with touch-sensitive surfaces, the addition of an ITO (indium tin oxygen) coating adds the exciting property of not only being transparent to the visible light part of the electromagnetic spectrum, but also of being electrically conductive. The logical result is that fine folk like [Sokol] simply had to use their newly acquired ITO-coated glass to make a button out of.

Here the easy option is of course to just use it as a capacitive sensor where the conductive ITO layer is used for the capacitive charge and the glass provides the insulator, but here we see it demonstrated how to create a pressure-sensitive implementation instead.

The measured conductivity on the ITO-coated glass in the video is pretty good, at just over 20 Ohm. This thus makes said capacitive button very easy to achieve. To make it a touch-sensitive button, two pieces of glass are used, with the ITO sides facing. Paper is used to create a spacer, after which the slight flex of the glass allows for the two ITO surfaces to touch, completing the circuit.

This is somewhat similar to how resistive touch screens work, with the position of the finger or stylus determined by the resistance between the two sides. In a hobbyist setup this would make it fairly easy to create a multi-position touch screen using just two pieces of glass and some firmware.

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Thingino Teaches Cheap IP Cameras New Tricks

July 29, 2026 by Tom Nardi 23 Comments

I recently found myself in the market for a few IP cameras to keep an eye on my Prusa 3D printers, and quickly found that the options on the market weren’t exactly ideal. Prusa does offer up an official camera, but the price for a pair of them was a bit more than I wanted to spend on the project. Conversely, there’s no shortage of cheap network-connected cameras available online, but they come with expenses of a different sort, namely proprietary software and cloud services I didn’t want or need.

Somewhere in the deep and dark recesses of this particular rabbit hole, I came across a Reddit post mentioning how a camera running the community-developed Thingino firmware could be plugged into Prusa’s remote printer monitoring scheme. It wasn’t a project I’d heard of previously, and sure enough, a search of the Hackaday back catalog showed we’d never come across it before.

My interest was already piqued, but the discovery that I already owned a supported camera sealed the deal. It was time to explore a new entry in one of my absolute favorite project categories: an open source replacement firmware that turns a cheap consumer device into something more than the sum of its parts.

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Filling High Pressure CO2 Tanks From Sugar Fermentation Gas

July 26, 2026 by Maya Posch 15 Comments

After previously using the fermenting of sugar to obtain ethanol fuel, [Hyperspace Pirate] figured that it’d be a waste to just blast the other half of the yeast production in the form of carbon dioxide into the air. This poses the slight problem that gaseous CO₂ is fairly bulky, while compressing it into a liquid isn’t exactly for the faint of heart. This of course means that it’s a fun challenge, involving a beach ball, vapor-compression and various compressors.

Although at room temperature compressing CO₂ into a liquid requires quite extreme pressures, if you lower it to freezing temperatures it becomes quite feasible to use more typical off-the-shell compressors.

In the video both oil-less and regular compressors are used, mostly because ultimately you want to get pure CO2 into the bottle, without oil or water. Here a few methods are explored, including a pre-cooler with the oil-less compressor as it cannot quite hit the same pressures. With a typical compressor linked to an oil-separator you can directly fill the tank, which is pretty nice, though even with this removal of water turned out to be a chore.

Desiccating the gas that comes out of the fermentation vat, is attempted using a converted water filter that’s filled with desiccant beads, but as the later tests show, this isn’t quite good enough to prevent moisture to make it into the bottle and clogging its nozzle. Of course, moisture here is more acceptable than oil for most applications, so with some more work this could be quite a feasible method to fill bottles with liquid CO₂ for various nefarious applications like paintball guns and more.

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