Turning Up The Heat On HT-PLA’s Marketing

PLA is probably the most-printed filament on the market these days, and is there any wonder? It’s cheap, it’s easy, and it doesn’t poison you (as quickly as its competitors, anyway). What it doesn’t do very well is take the heat. Polymaker’s new HT-PLA formulation promises to solve that, and [My Tech Fun] put those claims to the test in a recent video.

Polymaker claims its HT-PLA is heat-stable up-to 150 C, but still prints as easily as standard PLA at up to 300 mm/s. By “heat stable” they mean able to maintain dimensions and form at that temperature when not under any load, save perhaps its own weight. If you need high-temp mechanical properties, they also offer a glass-fiber infused HT-PLA-GF that they claim is heat resistant up to 110 C (that is, able to withstand load at that temperature) which is hard to sneeze at, considering you  you could print it on a stock Ender so long as you tossed a hardened nozzle on it.

Now it’s not a free lunch: to get the very best results, you do need to anneal the parts, which can introduce shrinkage and warping in HT-PLA, but that’s where HT-PLA-GF shines. If you want to see the results of the tests you can jump to 19:27 in the video, but the short version is that this is mechanically like PLA and can take the heat.

The verdict? If you like printing PLA and want to shove something in a hot car, you might want to try HT-PLA. Otherwise, it’s just like PLA. It prints like PLA, it looks like PLA, and when cold it behaves mechanically like PLA, which we suppose was rather what Polymaker was going for. There is no word yet on whether the additives that make it high-temp increase off-gassing or toxicity but since this stuff prints like PLA and can stand a little airflow, it should be easy to ventilate, which might make for fewer trade-offs when building an enclosure.

What do you think, will you be trying HT-PLA anytime soon? Let us know in the comments.

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Raspberry Pi Test Stand Tells You Which Glues To Use

Not all glues are created equal; or rather, not every glue is good for every application. But how is one to know which glue to use in which kinds of joints? The answer to that is not always clear, but solid numbers on the comparative strength of different glues are a great place to start.

To quantify what can ordinarily be a somewhat subjective process, there’s probably no one better than woodworker and hacker [Matthias Wandel], equipped as he is with his DIY strength-tester. Using its stepper-driven power to blast apart glued lap joints, [Matthias] measured the yield point of the various adhesives using a strain gauge connected to a Raspberry Pi.

His first round of tests had some interesting results, including the usually vaunted construction adhesive ending up in a distant last place. Also performing poorly, at least relative to its reputation and the mess it can cause, was the polyurethane-based Gorilla Glue. A surprise standout in overall strength was hot glue, although that seemed to have a sort of plastic yield mode. Ever the careful empiricist, [Matthias] repeated his tests using hardwoods, with remarkably different results; it seems that glues really perform better with denser wood. He also repeated a few tests to make sure every adhesive got a fair shake. Check out the video below for the final results.

It’s always good to see experiments like this that put what we often take for granted to the test. [John] over at the Project Farm channel on YouTube does this kind of stuff too, and even did a head-to-head test of epoxy adhesives.

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What Are Those Hieroglyphics On Your Laptop Charger?

Look on the back of your laptop charger and you’ll find a mess of symbols and numbers. We’d bet you’ve looked at them before and gleaned little or no understanding from what they’re telling you.

These symbols are as complicated as the label on the tag of your shirt that have never taught you anything about doing laundry. They’re the marks of standardization and bureaucracy, and dozens of countries basking in the glow of money made from issuing certificates.

The switching power supply is the foundation of many household electronics — obviously not just laptops — and thus they’re a necessity worldwide. If you can make a power supply that’s certified in most countries, your market is enormous and you only have to make a single device, possibly with an interchangeable AC cord for different plug types. And of course, symbols that have meaning in just about any jurisdiction.

In short, these symbols tell you everything important about your power supply. Here’s what they mean.

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Nuts And Bolts: Keeping It Tight

It’s not much of a stretch to say that without nuts and bolts, the world would fall apart. Bolted connections are everywhere, from the frame of your DIY 3D printer to the lug nuts holding the wheels on your car. Though the penalty for failure is certainly higher in the latter than in the former, self-loosening of nuts and bolts is rarely a good thing. Engineers have come up with dozens of ways to make sure the world doesn’t fall apart, and some work better than others. Let’s explore a few of these methods and find out what works, what doesn’t work, and in the process maybe we’ll learn a little about how these fascinating fasteners work.

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