DIY Nozzle Socks For Your 3D Printer

If you have a 3D printer, your nozzle and heater block are invariably covered in a weird goo consisting of decomposed and burnt plastic. There’s only one way around this – a nozzle sock, or a silicone boot that wraps around the heater block and stops all that goo from accumulating.

Right now, E3D sells silicone nozzle socks for their normal-sized heater blocks, with a release for their maxi-sized Volcano blocks coming shortly. [Ubermeisters] couldn’t wait, so he designed a 3D printed mold to cast as many Volcano nozzle socks as he could ever need.

The mold itself is taken from the mechanical drawings of the E3D Volcano hotend, printed in Proto Pasta HTPLA. To create the nozzle sock, this mold is filled with a goo made from GE Silicone I, mineral spirits, plaster of Paris, carbon powder, aluminum powder, titanium microspheres, and bronze powder colorant from Alumalite.

The mold is sprayed with release, filled with silicone goo, and slowly brought together. After a few hours, the silicone has cured, can be removed from the mold, and the flash can be cut away from the finished part. The end result is great — it fits the Volcano hotend well, and shouldn’t be covered in melted, burnt plastic in a week’s time.

All the files for the Volcano nozzle sock mold can be found on YouMagine. Alternatively, you could wait another month or two for E3D to release their ‘official’ Volcano nozzle sock.

Struggling Robot Made With DIY Soft Limbs

[Jonathan Grizou] is experimenting with robot designs, and recently stumbled upon a neat method for making soft robots. While his first prototype, a starfish like robot, doesn’t exactly “whelm” a person with it’s grace and agility, it proves the concept. Video after the break.

In this robot the frame is soft and the motor provides most of the rigidity for the structure. The soft parts of the frame have hardpoints embedded into them for mounting the motors or joining sections together. The sections are made with 3D printed molds. The molds hold the 3D printed hard points in place. Silicone is poured into the mold and left to cure overnight. The part is then demolded and is ready for use.

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Parent To The Power Wheels Rescue

If the [realjohnnybravo] is the one from the show, it appears he finally managed to get a girlfriend, marry her, and produce at least one son. As the old schoolyard rhyme goes, first comes love, then comes marriage, then comes filling the whole *!$&# backyard with brightly colored plastic garbage. One of these items, a Power Wheels quad bike,  suffered a blow from planned obsolescence leaving behind a traumatized child. [realjohnnybravo] decided to fix it.

He made frequent mention of how one could go to a store and purchase replacement gears for the toy. Perhaps it’s a German thing. Regardless, he shows experience with internet comments by justifying his adventure in gear manufacturing with, paraphrased, “I’m having fun and learning so back off you pedantic jerks.”

Resin casting is great, and is often overlooked vs 3D printing. He purchased some hardware store RTV silicone and some slow-cure resin. The faster cure resin would get too hot with this much volume and potentially burn.

Materials procured he took apart both gearboxes from the machine. He first made a silicone mold of the broken parts (from the good copies out of the working gearbox) and removed the master. Without a vacuum or pressure casting chamber, the molds came out a little rough and bubbly, but it’s nothing some work with a carpet knife can’t fix. For big gears like this it hardly matters. Next he poured the two part resin into the molds and waited.

After some finishing with regular woodworking tools the parts fit right into the voids in the defective gearbox. His son can once again happily whir around the lawn, until the batteries die anyway.

Learn Resin Casting Techniques: Cold Casting

Sometimes we need the look, feel, and weight of a metal part in a project, but not the metal itself. Maybe you’re going for that retro look. Maybe you’re restoring an old radio and you have one brass piece but not another. It’s possible to get a very metal like part without all of the expense and heat required in casting or the long hours in the metal fabrication shop.

Before investing in the materials for cold casting, it’s best to have practical expectations. A cold cast part will not take a high polish very well, but for brushed and satin it can be nearly indistinguishable from a cast part. The cold cast part will have a metal weight to it, but it clinks like ceramic. It will feel cool and transfers heat fairly well, but I don’t have numbers for you. Parts made with brass, copper, and iron dust will patina accordingly. If you want them to hold a bright shine they will need to be treated with shellac or an equivalent coating afterward; luckily the thermoset resins are usually pretty inert so any coating used on metal for the same purpose will do.

It is best to think of the material as behaving more or less like a glass filled nylon such as the kind used for the casing of a power tool. It will be stiff. It will flex a relatively short distance before crazing and then cracking at the stress points. It will be significantly stronger than a 3D printed part, weaker than a pure resin part, and depending on the metal; weaker than the metal it is meant to imitate.

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Tissue-Engineered Soft Robot Swims Like a Stingray

We’re about to enter a new age in robotics. Forget the servos, the microcontrollers, the H-bridges and the steppers. Start thinking in terms of optogenetically engineered myocytes, microfabricated gold endoskeletons, and hydrodynamically optimized elastomeric skins, because all of these have now come together in a tissue-engineered swimming robotic stingray that pushes the boundary between machine and life.

In a paper in Science, [Kevin Kit Parker] and his team at the fantastically named Wyss Institute for Biologically Inspired Engineering describe the achievement. It turns out that the batoid fishes like skates and rays have a pretty good handle on how to propel themselves in water with minimal musculoskeletal and neurological requirements, and so they’re great model organisms for a tissue engineered robot.

The body is a laminate of silicone rubber and a collection of 200,000 rat heart muscle cells. The cardiomyocytes provide the contractile force, and the pattern in which they are applied to the 1/2″ (1.25cm) body allows for the familiar undulating motion of a stingray’s wings. A gold endoskeleton with enough stiffness to act as a spring is used to counter the contraction of the muscle fibers and reset the system for another wave. Very clever stuff, but perhaps the coolest bit is that the muscle cells are genetically engineered to be photosensitive, making the robofish controllable with pulses of light. Check out the video below to see the robot swimming through an obstacle course.

This is obviously far from a finished product, but the possibilities are limitless with this level of engineering, especially with a system that draws energy from its environment like this one does. Just think about what could be accomplished if a microcontroller could be included in that gold skeleton.

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Beyond WD-40: Lubes for the Home Shop

If your shop is anything like mine, you’ve got a large selection of colorful cans claiming to contain the best and absolutely only lubricant you’ll ever need. I’ve been sucked in by the marketing more times than I care to admit, hoping that the next product will really set itself apart from the others and magically unstick all the stuck stuff in my mechanical life. It never happens, though, and in the end I generally find myself reaching for the familiar blue and yellow can of WD-40 for just about every job.

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Machine Shop Soaps Are Good, Clean Learning Fun

At first glance, it’s easy to dismiss the creation of custom bath soaps as far outside the usual Hackaday subject matter, and we fully expect a torrent of “not a hack” derision in the comments. But to be able to build something from nothing, a hacker needs to be able to learn something from nothing, and there is plenty to learn from this hack.

On the face of it, [Gord] is just making kitschy custom bath soaps for branding and promotion. Cool soaps, to be sure, and the drop or two of motor oil and cutting fluid added to each batch give them a little machine shop flair. [Gord] experimented with different dyes and additives over multiple batches to come up with a soap that looked like machined aluminum; it turns out, though, that adding actual aluminum to a mixture containing lye is not a good idea. Inadvertent chemical reactions excepted, [Gord]’s soaps and custom wrappers came out great.

So where’s the hack? In stepping way outside his comfort zone of machining and metalwork, [Gord] exposed himself to new materials, new techniques, and new failure modes. He taught himself the basics of mold making and casting, how to deal with ultra-soft materials, the chemistry of the soap-making process, working out packaging and labeling issues, and how to deal with the problems that come from scaling up from prototype to production. It may have been “just soap”, but hacks favor the prepared mind.