Seven Segment Clock Made From Scratch

[David Hopkins] built a seven segment clock, but not in a way you would think.  Typically, if one wants to make something like this, one would start off with some seven segment LEDs. [David] wanted to kick it up a notch and use RGB LEDs to get access to the wide array of different colors, but found off the shelf assemblies cost prohibitive. So, he did what any good hacker would do. He made his own.

clockThe easy part consists of Neopixels, an Arduino Nano and a DS3231 Real Time Clock. The hard part consists of Plasticard and a polymorph diffuser. Plasticard also goes by the name of Polystyrene and comes in sheets. [David] describes Polymorph as a type of moldable nylon that softens with heat, with a working temperature low enough that boiling water will suffice.

He was able to cut out the individual segments to make an impressive looking desk clock.

Building A Dead-On-Accurate Model Ford Pickup From Scratch

In a world filled with 3D printed this and CNC machined that, it’s always nice to see someone who still does things the old-fashioned way. [Headquake137] built a radio controlled truck body (YouTube link) from wood and polystyrene using just a saw, a Dremel, a hobby knife, and a lot of patience. This is one of those builds that blurs the lines between scale model and sculpture. There aren’t too many pickup trucks one might call “iconic” but if we were to compile a list, the 6th generation Ford F-series would be on it. [Headquake137’s] model is based on a 1977 F100.

ford-thumb2The build starts with the slab sides of the truck. The basic outline is cut into a piece of lumber which is then split with a handsaw to create a left and a right side. From there, [Headquake137’s] uses a Dremel to carve away anything that doesn’t look like a 1977 F100. He adds pieces of wood for the roof, hood, tailgate, and the rest of the major body panels. Small details like the grille and instrument panel are created with white polystyrene sheet, an easy to cut material often used by train and car modelers.

When the paint starts going on, the model really comes to life. [Headquake137] weathers the model to look like it’s seen a long life on the farm. The final part of the video covers the test drive of the truck, now mounted to a custom chassis. The chassis is designed for trails and rock crawling, so it’s no speed demon, but it sure does look the part riding trails out in the woods!

[Headquake137] managed to condense what must have been a 60 or 70 hour build down to a 14 minute video found below.

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A Different Kind of Plastic Shredder for 3D Filament Making

Haven’t you heard? You can make your own 3D filament nowadays from plastic granules (10X cheaper than filament), or even by recycling old plastic! Except if you’re recycling plastic you will have to shred it first…

[David Watkins] came up with a different way of shredding plastic. Typically we’ve seen shrunken versions of giant metal shredders used to dice up plastic into granules that can be melted down and then extruded back into filament. These work with a series of sharp toothed gears that kind of look like a stack of circular saw blades put together inside of a housing.

But that can be rather pricey. [David’s] method is super cheap, and you can do it at home with minimal tools, and maybe $10 or less worth of parts?

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Adding Recycling Codes To 3D Prints

Every little plastic bauble you interact with has some sort of recycling code on it somewhere. Now that we’re producing plastic 3D printed parts at home, it would be a good idea to agree on how to recycle all those parts, and [Joshua Pearce]’s lab at Michigan Tech has the answer; since we’re printing these objects, we can just print the recycling code right in the object.

The US system of plastic recycling codes is particularly ill-suited for identifying what kind of plastic the object in question is made of; there are only seven codes, while China’s system of plastic identification uses 140 identification codes. This system for labeling 3D printed parts borrows heavily from the Chinese system, assigning ABS as ‘9’, PLA as ’92’, and HIPS as ‘108’.

With agreed upon recycling codes, the only thing left to do is to label every print with the correct recycling code. That’s an easy task with a few OpenSCAD scripts – the paper shows off a wrench made out of HIPS labeled with the correct code, and an ABS drill bit handle sporting a number nine. 3D printing opens up a few interesting manufacturing techniques, and the research team shows this off with a PLA vase with a recycle code lithophane embedded in the first few layers.

Turning Plastic Milk Jugs into a Useful Tool

[Peter] obviously enjoys getting to work in his wood shop. He also likes turning things into other things. With his latest project, he combines his two hobbies by turning plastic milk jugs into a plastic joiner’s mallet.

[Peter] started out by collecting and “processing” the milk jugs. Milk jugs are commonly made with HDPE. HDPE is a petroleum-based plastic with a high strength-to-density ratio. It’s easy to recycle, which makes it perfect for this type of project. We’ve even seen this stuff recycled into 3D printer filament in the past. The “processing” routine actually just consists of cutting apart the jugs with a razor blade. [Peter] mentions in the past that he’s used a blender to do this with much success, but he’s unfortunately been banned from using the blender.

Next, all of the plastic pieces are piled up on a metal try to placed into a small toaster oven. They are melted into one relatively flat, solid chunk. This process is performed three times. The final step was to pile all three chunks on top of each other and melt them into one massive chunk of plastic.

While waiting for the plastic to melt together, [Peter] got to work on the handle. He put his woodworking skills to good use by carving out a nice wooden handle from a piece of cherry wood.  The handle was carefully shaped and sanded with a variety of tools. It is finished with some linseed oil for a nice professional look.

When the plastic was mostly melted together, [Peter] had to get to work quickly while the plastic was still soft. He pried the plastic off of the metal tray and stuffed it into a rectangular mold he made from some fiber board. He used a heat gun to soften the plastic as needed while he crammed it all into the mold. With the mold suitably stuffed, he closed it up and clamped it all shut.

Once the plastic cooled, [Peter] had to cut it into the correct shape and size. He took the solid chunk of plastic to his band saw to cut all the appropriate angles. He then used both a drill press and a chisel to cut the rectangular mounting hole for the handle. The plastic piece was then shaped into its final form using a belt sander. All that [Peter] had left to do was slide it up and only the handle. The shape of the handle and mounting hole prevent the plastic piece from flying off of the top of the handle. Check out the video below to see the whole process. Continue reading “Turning Plastic Milk Jugs into a Useful Tool”

Putting Lightning In Acrylic

Some folks at the i3Detroit hackerspace had an opportunity come up that would allow them to capture lightning in acrylic. They created a few Lichtenberg figures thanks to the help of a plastic tubing manufacturer, some lead sheet and a bunch of 1/2″ thick acrylic.

Lichtenberg figures are the 3D electrical trees found in paperweights the world over. They’re created through electrical discharge through an insulator, with lightning being the most impressive Lichtenberg figure anyone has ever seen. These figures can be formed in smaller objet d’art, the only necessity being a huge quantity of electrons pumped into the insulator.

This was found at Mercury Plastics’ Neo-Beam facility, a 5MeV electron accelerator that’s usually used to deliver energy for molecular cross linking in PEX tubing to enhance chemical resistance. For one day, some of the folks at i3Detroit were able to take over the line, shuffling a thousand or so acrylic parts through the machine to create Lichtenberg figures.

When the acrylic goes through the electron accelerator, they’re loaded up with a charge trapped inside. A quick mechanical shock discharges the acrylic, creating beautiful tree-like figures embedded in the plastic. There are a lot of pictures of the finished figures in a gallery, but if you want to see something really cool, a lead-shielded GoPro was also run through the electron accelerator. You can check out that video below.

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New 3D Printing Technique – Friction Welding

Even though 3D printers can fabricate complex shapes that would be nearly impossible to mill, they are not well suited to designs requiring bridging or with large empty spaces. To overcome this, [Scorch] has applied an easy plastic welding technique that works with both ABS and PLA. All you need is a rotary tool.

Friction welding” is the process of rubbing two surfaces together until the friction alone has created enough heat to join them. Industrially, the method is applied to joining large, metal workpieces that would otherwise require a time-consuming weld. In 2012, [Fran] reminded us of a toy from decades ago that allowed children to plastic weld styrene using friction. This modified method is similar to stick welding in that a consumable filler rod is added to the molten joint. Inspired by our coverage of [Fran], [Scorch] experimented and discovered that a stick of filament mounted into a Dremel works just as well for joining 3d prints.

That is all there is to it. Snip off a bit of filament, feed it into your rotary tool, and run a bead to join parts and shapes or do repairs. Friction welded plastic is shockingly strong, vastly superior to glued plastic for some joints. Another tool for the toolbox. See the videos below for [Scorch]’s demo.

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