Comparing PETG And PCTG Filaments

September 7, 2026 by Maya Posch 5 Comments

The average 3D printer owner knows a few types of filaments – PLA, ABS, somewhere in the middle, PETG. PCTG is another option that can be confusingly similar to PETG. Recently, [Igor Gaspar] of [My Tech Fun] took a poke at both types. He obtained both PETG and PCTG transparent filaments from the same manufacturer to compare them directly.

As we recently detailed in an article on PET polyesters, PETG is glycol-modified PET, meaning that some of the glycol monomers are replaced by CHDM monomers to create a more flexible and robust material. PCTG is very similar to PETG, except that more than half of the glycol monomers are replaced rather than less than half. This creates a PET-type material that has distinct physical properties from PETG, which might be desirable for some applications.

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How Charged Water Drops Induce Corrosion

September 6, 2026 by Maya Posch 11 Comments

Generally, we do not look at the gentle patter of raindrops on a surface with much concern, but according to a study by [Zhongyuan Ni] et al. in Nature, we should probably regard these droplets with a little scrutiny for their corrosion potential. What they found is that these drops can gather a significant electric potential as they gently slide down a surface, with over 1 kV measured. By first having droplets charge up on an insulating surface before hitting a target metal surface, they were able to induce significant corrosion.

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Saturn’s South Pole Is Apparently Decagon-Shaped

September 6, 2026 by Maya Posch 15 Comments

Saturn's north pole captured by Cassini in 2013. (Credit: NASA/JPL-Caltech/SSI/CICLOPS/Kevin M. Gill) — Saturn’s north pole captured by *Cassini* in 2013. (Credit: NASA/JPL-Caltech/SSI/CICLOPS/Kevin M. Gill)

Although some would argue that the hexagon is the bestagon, astronomers have discovered that Saturn appears to favor the ten-sided decagon on its south pole. This comes as its south pole has recently been confirmed to show a pattern that’s oddly ten-sided, per a recent research article by [Agustín Sánchez-Lavega] et al. in Science Advances.

Because Saturn is a gas giant, this naturally isn’t some gigantic planet-sized rock formation, but rather an interesting wave phenomenon in this massive gas bubble. The hexagon shape on its north pole had been known about for a while already, so it is perhaps not too surprising to find something similar on its south pole.

These shapes are generally the result of standing waves within a polar vortex, through the interaction of waves in Saturn’s atmosphere. For the north pole hexagon, the formation is driven by an intense eastward jet, but no similar wave had been reported for the planet’s south pole.

While in this paper a decagon shape is identified based on multiple observations, they postulate that it’s due to a meandering wave in the area rather than a jet as at the other pole. This clearly doesn’t make this wave pattern as obvious as the one at the north pole, but it provides another fascinating insight into fluid dynamics scaled up to a planetary gas giant.

Can AI Now Design PCBs That Just Work?

September 5, 2026 by Maya Posch 63 Comments

With the recent release of its GPT-6 Astra model, OpenAI explicitly pushed the claim that it is capable of designing complete circuit boards in KiCad, starting from a provided schematic and outputting a fully routed PCB that theoretically could be sent off to be manufactured. This of course raises the question whether this is just a nifty party trick that works under strictly controlled conditions like most auto-routing tools, or whether there’s more to it. In a recent [EEBench] blog post, OpenAI’s claims are put to the test.

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Pixel Watch 5 Demonstrates Good Repairability

September 5, 2026 by Maya Posch 18 Comments

Although we often find ourselves drowning in a seemingly unending sea of portable devices that are effectively e-waste once an internal component gives out, it’s good to remind ourselves that there are a few examples out there by large brands that manage to tick all the fancy feature boxes, while still being very much repairable. Case in point the Pixel Watch 5, a smart watch which much like its predecessor gets a 9/10 on [iFixit]’s repairability score.

No heat gun required, just undo the latch on the side of the watch. (Credit: iFixit, YouTube) — No heat gun required, just undo the latch on the side of the watch.

Despite featuring an IP68 rating, opening it is as easy as taking out a few screws to release its latch. This allows the back to swing open, with not a drop of glue in sight, just an O-ring gasket that keeps moisture out and can be reused many times. Digging into the guts, there are color-coded screws that guide one’s hand as the very modular design is taken apart in a matter of minutes.

Being able to simply unlatch the back, and also easily obtain spare parts are two aspects that are a very welcome sight indeed. Although it’s much easier to just glue everything together, something like this latch-and-gasket approach is something that we hope that more manufacturers will copy for these small devices.

It’s potentially also an idea for one’s next DIY smart watch project, as tempting as reaching for that tube of glue may seem.

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Fixing An Expensive Seagate LaCie Hard Drive Array

September 4, 2026 by Maya Posch 14 Comments

After the [Slow Mo Guys] acquired a 168 TB Seagate LaCie Thunderbolt 3-based RAID storage system back in 2019 to store their video footage, they were obviously slightly miffed when suddenly it would just refuse to power up. Naturally the device was now out of warranty, the product itself no longer produced and Seagate support was less than supportive, ergo they sent the device to [Mend it Mark] for an attempted repair.

At first inspection the device appeared to be basically unresponsive, with none of the four fans running and no signs of life other than a few lit LEDs on the main PCB after supplying power to it. After full disassembly and with no repair guide or schematics to go by [Mark] had to start from basics, first diagnosing whether all the power rails were turning on, which they weren’t.

Eventually this led to the NXP LPC11U6x-series MCU which acts as the main power management and monitoring chip in the system. [Mark] deduced that this MCU wasn’t turning on all the power rails because it was waiting for a signal from the fan controllers on the SATA backplane. With the MCU sending the right signals here, and the fans all working when directly supplied with power, ultimately it turned out that a single SI2319 or similar P-channel MOSFET in SOT-23 package near one of the fan connectors had gone faulty.

Replacing this one MOSFET seems to have fixed the RAID array, with it now happily powering up, although the real test will be once the [Slow Mo Guys] start shoving the HDDs back into it. Assuming that this was the sole fault in the system, then it was a very cheap fix in terms of materials. It’s a real shame that repair guides or schematics aren’t made available for devices like this, even if just after they stop being produced.

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Making A Pole Balance Itself With Propellers

September 4, 2026 by Maya Posch 19 Comments

A fun trick with a pole is to try to balance it so that it can stand on one end. This can be done in a few ways, such as by exerting a force on either end to counterbalance any force that threatens to make it fall over. The approach that [Peter Ryseck] chose was to cobble together what is effectively a flying drone for on top of a standing pole, without cheating such as by simply lifting it off the ground.

Getting to the point where the drone could react quickly enough to changes in the pole’s orientation was the hardest part, as the quieter, larger propellers also have a lot more inertia. This ruled out using 10″ blades, while triple 5″ blades seemed to work well enough. For the avionics a standard quadcopter control board and software is used, with the programming such that it’ll react appropriately without causing additional instabilities.

Naturally making this work took some trial and error, with issues like oscillations plaguing the system. One unexpected problem was that the pole – taken from a pool fishing net – was flexible enough to add its own instabilities to the system. In the video all these issues and their solutions are explained in detail, along with the ultimate result. One very neat solution here for example is to have the pole lean into the wind, which is a more stable configuration than insisting on having the pole be at a perfect ninety degrees with the ground.

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