When you first unwrap a shiny new roll of filament for your FDM printer, it typically has a bag of silica gel inside. While great for keeping costs low on the manufacturing side, is silica gel the best solution to keep your filament dry at home?

Frustrated with the consumable nature and fussy handling of silica gel beads, [Build It Make It] sought a more permanent way to keep his filament dry. Already familiar with activated alumina beads, he crafted a desiccant cylinder that can be popped into the oven all at once instead of all that tedious mucking about with emptying and refilling plastic capsules.

A length of aluminum intake pipe, some high temperature epoxy, and aluminum mesh are all combined to make a simple, sealed cylinder. During the process, he found that using a syringe filled with the epoxy led to a much more precise application to the aluminum cylinder, so he recommends starting out that way if you make these for yourself.

We suspect something with a less permanent attachment at one end would let you periodically swap out the beads if you wanted to try this hack with the silica beads you already had. Perhaps some kind of threaded pipe fitting? If you want a more active dryer, try making one with a Peltier. If you want to know just how dry your filament is getting, you could also put in a sensor. You might also wonder, do you really need to dry filament at all?

Anyone who has left their car windows open during a rainstorm will tell you the best way to dry the upholstery is to crank the AC and close the windows. A couple of hours later, presto — dry seats. The same can be said for 3D printer filament, and it’s pretty much what [Ben Krejci] is doing with this solid-state filament dryer.

The running gear for this build is nothing fancy; it’s just a standard thermoelectric cooling module and a fan. The trick was getting the airflow over the module right. [Ben] uses two air inlets on his printed enclosure to pull air from the cold side of the Peltier, which allows the air enough time in contact with the cold to condense out the water. It also allows sufficient airflow to keep the hot side of the module from overheating.

Water collection was a challenge, too. Water always finds a way to leak, and [Ben] came up with a clever case design incorporating a funnel to direct water away. The module is also periodically run in reverse to defrost the cold side heatsink.

The dehumidifier lives in a large tool cabinet with plenty of room for filament rolls and is run by an ESP32-C3 with temperature and humidity sensors, which allowed [Ben] to farm most of the control and monitoring out to ESPHome. The setup seems to work well, keeping the relative humidity inside the cabinet in the low 20s — good enough for PETG and TPU.

It’s an impressively complete build using off-the-shelf parts. For a different approach to solid-state filament drying, check out [Stefan]’s take on the problem.

Multi-filament printing can really open up possibilities for your prints, even more so the more filaments you have. Enter the 8-Track from [Armored_Turtle], which will swap between 8 filaments for you!

The system is modular, with each spool of filament installed in a drybox with its own filament feeder .The dryboxes connect to the 8-Track changer via pogo pins for communication and power. While [Armored_Turtle] is currently using the device on a Voron printer, he’s designed it so that it can be easily modified to suit other printers. As it’s modular, it’s also not locked into running 8 filaments. Redesigning it to use more or less is easy enough thanks to its modular design.

The design hasn’t been publicly released yet, but [Armored_Turtle] states they hope to put it on Github when it’s ready. It’s early days, but we love the chunky design of those actively-heated drybox filament cassettes. They’re a great step up from just keeping filament hanging on a rod, and they ought to improve print performance in addition to enabling multi-filament switching.

We’ve seen some other neat work in this space before, too. Video after the break.

[Thanks to Keith Olson for the tip!]

Accessibility devices are a wonder of modern technology, allowing people with various needs to interact more easily with the world. From prosthetics to devices to augment or aid someone’s vision or hearing, devices like these can open up many more opportunities than would otherwise exist. A major problem with a wide array of these tools is that they can cost a fortune. [3D Printy] hoped to bring the cost down for Braille trainers which can often cost around $1000.

Braille trainers consist of a set of characters, each with six pins or buttons that can be depressed to form the various symbols used in the Braille system. [3D Printy]’s version originally included six buttons, each with a set of springs, that would be able to pop up and down. After some work and real-world use, though, he found that his device was too cumbersome to be effective and redesigned the entire mechanism around flexible TPU filament, allowing him to ditch the springs in favor of indentations and buttons that snap into place without a dedicated spring mechanism.

The new design is modular, allowing many units to be connected to form longer trainers than just a single character. He’s also released his design under the Creative Commons public domain license, allowing anyone to make and distribute these tools as they see fit. The design also achieves his goal of dramatically reducing the price of these tools to essentially just the cost of filament, provided you have access to a 3D printer of some sort. If you need to translate some Braille writing and don’t want to take the time to learn this system, take a look at this robotic Braille reader instead.

Thanks to [George] for the tip!

[Stefan] from CNC Kitchen explored an unusual approach to a multi-material print by making custom PLA filament with a TPU core to make it super-tough. TPU is a flexible filament whereas PLA is hard almost to the point of being brittle. The combo results in a filament with some unusual properties, inviting some thoughts about what else is possible.

[Stefan]’s video covers a few different filament experiments, but if you’d like to see the TPU-PLA composite you can skip ahead to 18:15. He first creates the composite filament by printing an oversized version on a 3D printer, then re-forming it by running it through a Recreator to resize it down to 1.75 mm.

We have seen this technique of printing custom filaments before, which is useful to create DIY multi-color filaments in small quantities right on a 3D printer’s print bed with no special equipment required. This is an effective method but results in filament with a hexagonal profile, which works but isn’t really ideal. By printing his custom composite at 4 mm diameter then resizing the filament down to 1.75 mm, [Stefan] was able to improve overall printability.

That being said, TPU and PLA have very different characteristics and don’t like to adhere to one another so the process was pretty fiddly. TPU-cored PLA might be troublesome and uncooperative to make, but it can be done with some patience and fairly simple equipment.

Despite the difficulties, test prints were pretty interesting. PLA toughness was roughly doubled and under magnification one can see a lattice of TPU strands throughout the prints which are unlike anything else. Check it out in the video, embedded below.