Weed Eater String Made From Plastic Bottles

For those who don’t mind constantly adding tiny but measurable amounts of microplastics to their landscaping, string trimmers are an excellent way of maintaining edging around garden beds, trimming weeds, or maintaining ground covers on a steep hill. One problem with them, though, is that not only is the string consumable but it can be expensive. Plus, if you have a trimmer with a proprietary spool you need to hope the company never goes out of business. Or, you can simply refill your string spool with this handy tool.

The build uses plastic bottles to create the string from what would likely become garbage anyway. First, a sharp roller-style knife slices the plastic into a long thin strip. Once cut, it is fed through a heater similar to a hot end on a 3D printer which allows the plastic to be deformed or forged into a cylinder. From there the plastic is added onto a spool, which also has the motor in it that drives the entire mechanism. In this case it is using an old variable-speed drill.

From the comments on the video, there is some discussion about the economics of using this string in a weed eater. It’s likely the plastic won’t last as long as specialty string trimmer string, and the time and expense of making the plastic may never save much money. But we have to give credit to the ingenuity nonetheless. And, if you’re really into recycling plastic just for the sake of keeping it out of the landfill, there are plenty of other ways to go about accomplishing that goal.

I will NEVER buy weed whip line again! from landscaping

Recycling Plastic Into Filament

Plastic is a remarkable material in many ways. Cheap, durable, and versatile, it is responsible for a large percentage of the modern world we live in. As we all know, though, it’s not without its downsides. Its persistence in the environment is quite troubling, so any opportunity we can take to reduce its use is welcome. This 3D printed machine, although made out of plastic, is made out of repurposed water bottles that have been turned into the filament for the 3D printer.

While there’s not too much information available on the site, what we gather is that the machine cuts a specific type of plastic water bottle made out of PET plastic into strips, and then feeds the strips into a heated forming tool. The tool transforms the strips into the filament shape and spools them so they are ready to feed back into a 3D printer. As a proof of concept, it seems as though this machine was made from repurposed plastic, but it could also be made using whatever filament you happen to have on hand.

As far as recycling goes, this is a great effort to keep at least some of it out of landfills and oceans. Unfortunately, plastic can’t be recycled endlessly like metal, as it will eventually break down. But something like this could additionally save on some filament costs for those with access to these types of bottles. Other options for creating your own filament also include old VHS tapes, but you will likely need a separate machine for that.

Finely Machined Valve Controls Miniature RC Hydraulics

Hydraulic components are the industrial power transmission version of LEGO. Pumps, cylinders, valves – pretty much everything is standardized, and fitting out a working system is a matter of picking the right parts and just plumbing everything together. That’s fine if you want to build an excavator or a dump truck, but what if you want to scale things down?

Miniature hydraulic systems need miniature components, of which this homebrew hydraulic valve made by [TinC33] is a great example. (Video embedded below.) If you’re curious about why anyone would need these, check out the tiny hydraulic cylinders he built a while back, wherein you’ll learn that miniature RC snowplows are a thing. The video below starts with a brief but clear explanation about how hydraulic circuits work, as well as an explanation of the rotary dual-action proportional valve he designed. All the parts are machined by hand in the lathe from aluminum and brass stock. The machining operations are worth watching, but if you’re not into such things, skip to final assembly and testing at 13:44. The valve works well, providing very fine control of the cylinder and excellent load holding, and there’s not a leak to be seen. Impressive.

[TinC33] finishes the video with a tease of a design for multiple valves in a single body. That one looks like it might be an interesting machining challenge, and one we’d love to see.

Thanks to [mgsouth] for the tip.

Heated DryBox Banishes Filament Moisture For Under $20

There has been a lot of activity from [Richard Horne] regarding 3D printing filaments lately; most recently he has shared two useful designs for upping one’s filament storage and monitoring game. The first is for a DIY Heated DryBox for 3D printing filament. It keeps filament dry not just by sealing it into a plastic box with some desiccant, but by incorporating a mild and economical heater intended for reptile habitats inside. Desiccant is great, but a gently heated enclosure can do wonders for driving away humidity in the right environment. The DryBox design also incorporates a handy little temperature and humidity sensor to show how well things are working.

Spool-mounted adapter for temperature and humidity sensor (and desiccant) to monitor storage bag conditions.

The second design is a simple spin-off that we particularly liked: a 3D printed adapter that provides a way to conveniently mount one of the simple temperature and humidity sensors to a filament spool with a desiccant packet. This allows storing a filament spool in a clear plastic bag as usual, but provides a tidy way to monitor the conditions inside the bag at a glance. The designs for everything are on Thingiverse along with the parts for the Heated DryBox itself.

[Richard] kindly shares the magic words to search for on eBay for those seeking the build’s inexpensive key components: “15*28CM Adjustable Temperature Reptile Heating Heater Mat” and “Mini LCD Celsius Digital Thermometer Hygrometer Temperature Humidity Meter Gauge”. There are many vendors selling what are essentially the same parts with minor variations.

Since the DryBox is for dispensing filament as well as storing it, a good spool mounting system is necessary but [Richard] found that the lack of spool standardization made designing a reliable system difficult. He noted that having spool edges roll on bearings is a pretty good solution, but only if one doesn’t intend to use cardboard-sided spools, otherwise it creates troublesome cardboard fluff. In the end, [Richard] went with a fixed stand and 3D printable adapters for the spools themselves. He explains it all in the video, embedded below.

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Towards Sensible Packaging For 3D Printer Filament

Filament-based 3D printers are remarkably wasteful. If you buy a kilogram of filament from your favorite supplier, the odds are that it will come wrapped around a plastic spool weighing about 250 grams. Use the filament, and that spool will be thrown in the trash. Very, very few products have such wasteful packaging as 3D printer filament, with the possible exception of inkjet cartridges or getting a receipt with your purchase at CVS.

For the last few years, [Richard Horne], better known as RichRap, has been working towards a solution to the problem of the wasteful spools for 3D printer filament. Now, it looks like he has a solution with the MakerSpool. It’s the perfect solution for a 3D printing ecosystem that doesn’t waste 20% of the total plastic on packaging.

The design of the MakerSpool is fairly straightforward and also 3D printable. It’s a plastic filament spool, just a shade over 200mm in diameter, consisting of two halves that screw together. Add in some RepRap ‘teardrop’ logos, and you have a spool that should fit nearly any machine, and will accept any type of filament.

The trick with this system is, of course, getting the filament onto the spool in the first place. Obviously, filament manufacturers would have to ship unspooled filament that’s somehow constrained and hopefully vacuum packed. Das Filament, a filament manufacturer out of Germany, has already tested this and it looks like they have their process down. It is possible to ship a kilogram of 1.75 filament without a spool, and held together with zip ties. Other filament manufacturers also have packaging processes that are amenable to this style of packaging.

Whether this sort of packing will catch on is anyone’s guess, but there are obvious advantages. There is less waste for the environmentalists in the crowd, but with that you also get reduced shipping costs. It’s a win-win for any filament manufacturer that could also result in reduced costs passed onto the consumer.

Mini Spool System For 3D Printing Pen Tidies Things Up

3D printing pens may be toys to some, but they can be genuinely useful tools to repair 3D prints, rescue a support structure, or weld together different pieces. However, [BManx2000] found that the way the filament simply sticks out of the back of a 3D printing pen like a bizarre tailfeather was troublesome.

The solution? A Mini Spool System for 3D Printing Pens, with which you can use your 3D printing pen to weld together the parts after printing them. The unit holds 1.75mm filament coiled under its own tension in a tidy package that doesn’t interfere with feeding. Since different 3D pens are shaped differently, the interface to the pen is a separate piece that can be modified or changed as needed without affecting the rest of the design.

We’ve seen some interesting innovations with filament holders before, like this entirely 3D printed filament holder, but a mini spool for a 3D pen is definitely a new one.

DIY Wire Spooler With Clever Auto-Tensioning System

[Solarbotics] have shared a video of their DIY wire spooler that uses OpenBeam hardware plus some 3D printed parts to flawlessly spool wire regardless of spool size mismatches. Getting wire from one spool to another can be trickier than it sounds, especially when one spool is physically larger than the other. This is because consistently moving wire between different sizes of spools requires that they turn at different rates. On top of that, the ideal rate changes as one spool is emptying and the other gets larger. The wire must be kept taut when moving from one spool to the next; any slack is asking for winding problems. At the same time, the wire shouldn’t be so taut as to put unnecessary stress on it or the motor on the other end.

There aren’t any build details but the video embedded below gives a good overview and understanding of the whole system. In the center is a tension bar with pulleys on both ends though which the wire feeds. This bar pivots at the center and takes up slack while its position is encoded by turning a pot via a 3D printed gear. Both spools are motor driven and the speed of the source spool is controlled by the position of the tension bar. As a result, the bar automatically takes up any slack while dynamically slowing or speeding the feed rate to match whatever is needed.

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