Testing Whether Heated Chambers Help Brittle Filaments

March 17, 2026 by Maya Posch 7 Comments

Some FDM filaments are pretty brittle even if properly dried and stored, especially those which contain carbon fiber (CF) or similar additives like glass fiber (GF). This poses a problem in that these filaments can snap even within the PTFE tube as they’re being guided towards the extruder. Here a community theory is that having an actively heated chamber can help prevent this scenario, but is it actually true? [Dr. Igor Gaspar] of the My Tech Fun YouTube channel gave this myth a try to either confirm or bust it.

The comments suggested that heating the chamber to 65°C will help, but there’s little information online to support this theorem. To test the claim, a heated chamber was used along with a bending rig to see at which angle the filament would snap. In total five different filaments from three manufacturers (Polymaker, Qidi and YXPolyer) were tested, including Qidi’s PET-GF and PAHT-GF as the sole non-CF filaments.

A big question is how long exactly the filament will spend inside the heated chamber after making its way from the spool, which would be about 2.5 minutes with a 500 mm tube. For the test 5 minutes was used for the best possible result. Despite this, the results show that even with the standard deviation kept in mind, the heating actually seems to make the filaments even more brittle.

Considering that in general CF seems to simply weaken the polymer matrix after printing, this finding adds to the question of whether these CF and GF-infused filaments make any sense at all.

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Hacking The System In A Moral Panic: We Need To Talk

March 17, 2026 by Jenny List 95 Comments

It seems that for as long as there have been readily available 3D printers, there have been moral panics about their being used to print firearms. The latest surrounds a Washington State Legislature bill, HB2320, which criminalises the printing of unregistered guns. Perhaps most controversially, it seeks so impose a requirement on printers sold in the state to phone home and check a database of known firearms and refuse to print them when asked.

This has drawn a wave of protest from the 3D printing community, and seems from where we are sitting to be a spectacularly ill-conceived piece of legislation. It’s simply not clear how it could be implemented, given the way 3D printers and slicing software actually work.

Oddly This Isn’t About Firearms

The root of the problem with this bill and others like it lies in ignorance, and a misplaced belief in the power of legislation. Firearms are just the example here, but we can think of others and we’re sure you can too. Legislators aren’t stupid, but by and large they don’t come from technology or engineering backgrounds.

Meanwhile they have voters to keep happy, and therefore when a moral panic like this one arises their priority is to be seen to be doing something about it. They dream up a technically infeasible solution, push to get it written into law, and their job is done. Let the engineers figure out how to make it work. Continue reading “Hacking The System In A Moral Panic: We Need To Talk” →

Two test towers, showing the palette potential of three (R, B, Y) filaments.

FullSpectrum Is Like HueForge For 3D Models, But Bring Your Toolchanger

March 17, 2026 by Tyler August 20 Comments

Full-color 3D printing is something of a holy grail, if nothing else, just because of how much it impresses the normies. We’ve seen a lot of multi-material units in the past few years, and with Snapmaker’s U1 and the Prusa XL, it looks like tool changers are coming back into vogue. Just in time, [Ratdoux] has a fork of OrcaSlicer called FullSpectrum that brings HueForge-like color mixing to tool-changing printers.

The hook behind FullSpectrum is very simple: stacking thin layers of colors, preferably with semi-translucent filament, allows for a surprising degree of mixing. The towers in the image above have only three colors: red, blue, and yellow. It’s not literally full-spectrum, but you can generate surprisingly large palettes this way. You aren’t limited to single-layer mixes, either: A-A-B repeats, and even arbitrary patterns of four colors are possible, assuming you have a four-head tool-changing printer like the Snapmaker U1 this is being developed for.

FullSpectrum is, in fact, a fork of Snapmaker’s fork of OrcaSlicer, which is itself forked from Bambu Slicer, which forked off of PrusaSlicer, which originated as a fork of Slic3r. Some complain about the open-source chaos of endless forking, but you can see in that chain how much innovation it gets us — including this technique of color mixing by alternating layers.

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Recycled Plastic Compression Molding With 3D-Printed Molds

March 16, 2026 by Maya Posch 10 Comments

Recycling plastic at home using 3D printed molds is relatively accessible these days, but if you do not wish to invest a lot of money into specialized equipment, what’s the most minimal setup that you can get away with? In a recent [future things] video DIY plastic recycling is explored using only equipment that the average home is likely to have around.

Lest anyone complain, you should always wear PPE such as gloves and a suitable respirator whenever you’re dealing with hot plastic in this manner, just to avoid a trip to the emergency room. Once that issue is taken care of, there are a few ways of doing molding, with compression molding being one of the most straightforward types.

With compression molding you take two halves of a mold, and one half compresses the material inside the other half. This means that you do not require any complex devices like with injection molding: just a toaster oven or equivalent to melt the plastic, which is LDPE in this example. The scrap plastic is placed in a silicone cup before it’s heated so that it doesn’t stick to the container.

The wad of goopy plastic is then put inside the bottom part of the mold before the top part is put in place and squeezed by hand until molten plastic comes out of the overflow opening(s). After letting it fully cool down, the mold is opened and the part released. Although the demonstrated process can be improved upon, it seems to work well enough if you are aware of the limitations. In terms of costs and parts required it’s definitely hard to come up with a cheaper way to do plastic molding.

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How I 3D Printed My Own Lego-Compatible Train Bridges

March 16, 2026 by Lewin Day 38 Comments

Lego train sets have been available for decades, now. The Danish manufacturer long ago realized the magic of combining its building block sets with motors and plastic rails to create real working railways for children and adults to enjoy. Over the years, Lego has innovated through several generations of trains, from classic metal-rail systems to the more modern IR and later Bluetooth-controlled versions. The only thing largely missing over all that time, though…? A bridge!

Yes, Lego has largely neglected to build any bridges for its mainstream train lineup. There are aftermarket solutions, and innovative hacks invented by the community, all with their own limitations and drawbacks. This glaring oversight, though, seemed like a perfect opportunity to me. It was time to fire up the 3D printer and churn out a fully-realized Lego rail bridge of my very own.

Bridges Are Hard

I’ve experimented with building Lego rail bridges before, using standard track and household objects like cardboard, books, and beer. Unfortunately, it can be very difficult to support the track evenly at the joints which occur every 150mm, and derailments are common. Credit: author

There’s actually a good reason Lego bridges aren’t a big thing in the company’s own product lineup, beyond a few obscure historical parts. This is probably because they aren’t very practical. Lego locomotives are not particularly strong haulers, nor do they have excellent grip on the rails, and this makes them very poor at climbing even mild grades. Any official Lego bridge would have to be very long with a shallow slope just to allow a train to climb high enough to clear a locomotive on a track below. This would end up being an expensive set that would probably prove unpopular with the casual Lego train builder, even if the diehard enthusiasts loved it.

There are third-party options available out there. However, most rely on standard Lego track pieces and merely combine them with supports that hold them up at height. This can work in some cases, but it can be very difficult to do cool things like passing a Lego train under a bridge, for example. It can be hard to gain enough height, and the short length of Lego track pieces makes it hard to squeeze a locomotive between supports. Continue reading “How I 3D Printed My Own Lego-Compatible Train Bridges” →

A Smart Printer Enclosure For The Open Source World

March 15, 2026 by Ian Bos 18 Comments

3D printing has had its time to spread its wings into the everyday home, yet many of those homes lack the proper ventilation to prevent the toxic VOCs from escaping. Because of this, [Clura] has put together an entire open-sourced smart enclosure for most open concept printers.

While certain 3D printers or filament choices lend themselves to being worse than others, any type of plastic particles floating around shouldn’t find their way into your lungs. The [Clura] enclosure design includes HEPA and carbon filters in an attempt to remove this material from the air. Of course, there’s always the choice to have a tent around your printer, but this won’t actually remove any VOCs and air located inside a simple enclosure will inevitably escape.

What makes this enclosure different from other, either commercial or open-source designs, is the documentation included with the project. There are kits available for purchase, which you may want for the custom PCB boards for smart features such as filament weighing or fume detection. Even still, if you don’t want to purchase these custom boards the Gerber files are available on their GitHub page.

As smart as this enclosure is, it still won’t fix the issues of what happens to the toxins in your print after it’s done printing. If you are interested in this big picture question, you are not alone. Make sure to stay educated and help others learn by checking out this article here about plastic in our oceans.

Selective Ironing Adds Designs To 3D Prints

March 12, 2026 by Donald Papp 9 Comments

While working on a project that involved super-thin prints, [Julius Curt] came up with selective ironing, a way to put designs on the top surface of a print without adding any height.

For those unfamiliar, ironing is a technique in filament-based 3D printing that uses the extruder to smooth out top surfaces after printing them. The hot nozzle makes additional passes across a top surface, extruding a tiny amount in the process, which smooths out imperfections and leaves a much cleaner surface. Selective ironing is nearly the same process, but applied only in a certain pattern instead of across an entire surface.

Selective Ironing can create patterns by defining the design in CAD, and using a post-processing script.

While conceptually simple, actually making it work was harder than expected. [Julius] settled on using a mixture of computer-aided design (CAD) work to define the pattern, combined with a post-processing script. More specifically, one models the desired pattern into the object in CAD as a one-layer-tall feature. The script then removes that layer from the model while applying the modified ironing pattern in its place. In this way, one can define the pattern in CAD without actually adding any height to the printed object. You can see it in action in the video, embedded below.

We’ve seen some interesting experiments in ironing 3D prints, including non-planar ironing and doing away with the ironing setting altogether by carefully tuning slicer settings so it is not needed. Selective Ironing is another creative angle, and we can imagine it being used to embed a logo or part number as easily as a pattern.

Selective Ironing is still experimental, but if you find yourself intrigued and would like to give it a try head over to the GitHub repository where you’ll find the script as well as examples to try out.

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