Madness Or Genius? FDM Printing With Resin

November 17, 2022 by Al Williams 29 Comments

We aren’t sure what made him think of it, but [Proper Printing] decided to make an FDM printer lay down resin instead of filament. Why? We still aren’t sure, but we admire the effort nonetheless. In principle, extruding resin shouldn’t be much different than other liquid things you print like icing or concrete. Then you’d need to UV-cure the viscous liquid quickly. In fact, they wound up making up a paste-like resin using several chemicals and a filler.

Armed with the paste, it would seem like the big obstacles would be over. Instead of part cooling fans, the printer now has two laser heads focused on the print area. Printing in vase mode avoids some problems, but the first few attempts were not very successful.

With a bit of perseverance, the setup did work — for a while. More fine tuning got acceptable results. However, he eventually changed the filler material and got a passable Benchy to print. Nothing to be proud of, but recognizable. Honestly, we were surprised that the laser’s didn’t cure the material still inside the nozzle and cause terrible clogs.

Why put this much effort into doing this? We have no idea. Should you try it? Probably not. Of course, being able to print a paste has its own value. Perhaps delivering glue or solder paste, for example. But you generally won’t need to make tall prints with that kind of material. Then again, we’ve never been opposed to doing something “just because.”

After all, why make a musical instrument out of a Game Boy? Why make a modem with tin cans? You might as well extrude resin.

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TV Repair By Mail

November 17, 2022 by Al Williams 49 Comments

I don’t think there was ever a correspondence school called the “Close Cover Before Striking School” but since book matches — which used to be a thing when most people smoked — always had that text on them anyway perhaps there should have been. There was a time when electronic magazines, billboards, and even book matches were constantly bombarding us with ads to have a career in electronics. Or computers. Or TV repair. So while we think of distance learning as a new idea, really it is just the evolution of these old correspondence schools which date back quite some time.

How far exactly? Hard to say. There’s evidence of some distance learning going back as far as 1728. In 1837, there was a correspondence course to learn shorthand. By 1858, the University of London started its external program for correspondence work and the University of Chicago had a home study division in 1892. Radio was an early choice of topic, too. In the United States, the United Wireless Telegraph company started a training school — later the Marconi Institute — in 1909. However, it is doubtful that there was any correspondence training going on there until much later.

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Tiny Palm-Sized Crossbow Build Is Cute And Dangerous

November 17, 2022 by Lewin Day 17 Comments

Crossbows were a major development in the history of weaponry. They enabled lesser-skilled soldiers to shoot arrows at great speed in a compact form-factor. You can now build your own tiny version, thanks to this creation from [Maciej Nowak].

The main body of the crossbow was cut from a piece of aluminium bar stock, being shaped with an angle grinder. A slot was then machined to mount the crossbar and pulleys. A round piece of aluminium tube serves as a spring holder, and the spring is tensioned via pulling back a length of sailing rope to rest on a latch. The latch is released by a small trigger, just like on a full-size crossbow.

The arrows (or bolts, more typically) were made by machining skewers and giving them hard metal tips cut from nails. This enables them to penetrate apples, and presumably other fruits. They fly straight enough to reliably hit a target from a meter or two away.

We’ve seen other crossbow builds before, like this one that fires cannonballs! Just be careful where you aim, and don’t get yourself or anyone else hurt.

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Number Stations Gone Wild

November 17, 2022 by Al Williams 18 Comments

[Ringway Manchester] has an interest in numbers stations. These mysterious stations send presumably coded numbers or other coded information. However, it is rare that anyone claims credit for these stations. Normally they operate with military-like precision, adhering to strict operating schedules and sending out their messages error-free. [Ringway] looks at five times when things didn’t go as planned for these spy stations.

Perhaps it isn’t surprising, however, as machines have likely replaced human operators. That makes them prone to errors when the computers go awry. Many of the errors are ones of frequency, where two number stations wind up transmitting at once. We suppose spies all use the same few frequencies. Some, however, also had computers go haywire and start going through the alphabet which, of course, could have been part of some secret message protocol, but appeared more likely to be a simple mistake.

We were amused, though, to hear the story of a Czech spy station that not only had a licensed call sign but would send QSL cards to people who reported reception. Perhaps they didn’t get the memo about secrecy!

We’ve listened to a few number stations in our time. If you don’t have a suitable antenna, you can always try hunting them online. But don’t expect to catch them making any mistakes.

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A 12" LCD screen sits between speakers (on lower half of bezel) and joycon controllers are attached on the upper half of the bezel.

Portable Monitor Extension For Nintendo Switch

November 16, 2022 by Navarre Bartz 7 Comments

Handheld consoles are always a tradeoff between portability and screen real estate. [Pavlo Khmel] felt that the Nintendo Switch erred too much on the side of portability, and built an extension to embiggen his Switch. (YouTube)

[Khmel] repurposed a Dell XPS 12 LCD panel for the heart of this hack and attached it to an LCD controller board to serve as an external monitor for the Switch. A 3D printed enclosure envelops the screen and also contains a battery, speakers, and a dock for the console. Along the top edges, metal rails let you slide in the official Joy-Cons or any number of third party controllers, even those that require a power connection from the Switch.

Since the Switch sees this as being docked, it allows the console to run faster and at higher resolution than if it were in handheld mode. The extension lasts about 5 hours on battery power, and the Switch inside will still be fully charged if you don’t mind being constrained to its small screen while you charge it’s bigger-screened exoskeleton.

Need more portable goodness? Be sure to check out our other handheld and Nintendo Switch hacks.

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Better Sheet Metal Parts With Chemistry

November 16, 2022 by Al Williams 7 Comments

[Applied Science] wanted to make some metal parts with a lot of holes. A service provider charged high tooling costs, so he decided to create his own parts using photochemical machining. The process is a lot like creating PC boards, but, of course, there are some differences. You can see the video of the results, below.

Some of the parts could be made in different ways like water jet cutting or even stamping. However, some things — like custom screens — are only really feasible to do with a chemical process like this.

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Crazy Bike Frame Made Out Of 147 Nuts

November 16, 2022 by Lewin Day 39 Comments

Bike frames are most commonly made out of steel. If you’ve got money for something nicer though, you might go with something in aluminium or carbon fiber. [The Q] went completely off-the-wall with this build, though, constructing a bicycle frame out of 147 nuts.

Yes, a variety of nuts in various sizes were laid out and welded together to make the frame. The overall layout is a conventional diamond frame, albeit constructed out of many nuts stuck together rather than with tubes. Notably though, several important areas aren’t made in this way. The front and rear dropouts are made of sheet steel, and the bottom bracket, seat post mount, and headstem are all made of steel tube. After welding, the bike was given an attractive coat of grey paint. It was then laced up with the usual running gear and given a set of chunky mountain bike tires.

We wouldn’t want to push this frame too hard over bumps and jumps. The video only shows the nuts being joined with tack welds, and the front forks look particularly fragile. One suspects a decent shock loading could snap parts of the frame apart. Overall, though, it’s an eye-catching bike that has plenty of easy places to attach a lock. For an ultra-fashionable city-bound cruiser, it would be hard to beat.

We’ve featured some weird and wonderful bikes over the years, including this tasteful plywood design. Video after the break.

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