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

29 thoughts on “Weed Eater String Made From Plastic Bottles

  1. My 1950 model ‘ankle’ mower is better.

    I rate it at about 6th grade (size of ankle it can cut clean through).

    They made a castrated, modern, safer version. Sickle bar mower. Auto shutoff and other pansy features.

    This person is imputing a very low value to his time. Trimmer line is cheap and this improvised stuff will tangle and break constantly.

      1. No. The one that like an giant unguarded buzzcut beard trimmer. Two blades with the top one going back and forth, about 40 cutting openings each of which can cut through a gradeschooler’s ankle or a 2 inch sapling. 40 grade schoolers at once would stall the engine though.

  2. maybe this is stupid but last time i shopped for trimmer line i noticed that i could buy 100x as much of it for 4x the price, or something…so i bought an 855 ft spool of .095″ nylon for $27 in 2014 and i haven’t even used 10% of it

    1. same here – except ive been using .105 line in place of .085 and .095. I don’t do nearly as much as I used to weed-eater wise, but if I can load one spool or run half a dozen precuts for what a full roll of .065 or .085 would do, screw it.

  3. don’t guilt trip me about microplastics, and no, weedeater line is cheap and seems to last forever (I mean it took like 2 years to go though the stuff that came with it)

  4. In a Popular Mechanics, likely of the 70s or 80s, I saw an article, or might just have been a home hint page about how to make swivelling plastic blades for a weed whacker. Can’t remember exactly what they cut them from, might have been something like the lid of a 5 gallon pail that something came in (Like paint, laundry detergent, cat litter, ice melter) anyway, they were supposed to stand up way longer than a reel of line. Not sure if the google books search is good enough these days to pull it out, but I’ll give it a spin tomorrow when I’m awaker and might remember better keywords.

  5. “For those who don’t mind constantly adding tiny but measurable amounts of microplastics to their landscaping” –> THIS!
    I really wonder why nobody realizes that those big spools of nylon don’t magically “disappear”, but have to go somewhere.
    In France, in 2025 it will be mandatory for any new washing machine sold to include a microplastic filter, to avoid the large amount of microplastic particles released by clothes to be disseminated in the environment.
    But while your clothes are being washed, you can go outside and disseminate dozens of meters of nylon string in your garden. Just silly…
    Those string strimmers should be simply forbidden ASAP!

    1. I’m quite curious how a microplastic filter can work without also being an everything else filter and getting clogged almost immediately. Is there some kind of chemical ‘stickiness’ that is used on the plastics?

    2. Meh… forbidden. Do you have any better substitute for them? I’m not saying that the plastic waste (in general, nylon strings included) is not a problem, but just forbidding something without having a good substitute just doesn’t work. I’d rather use some biodegradable plastics for such applications, but OTOH I guess there might be some problems such as faster wear or some other worse mechanical properties, or that it might degrade its properties over time.

      1. Unfortunately, so called “biodegradable” plastics like PLA is in reality degradable only in hjgh temperature composting plants, not in natural environment. So it’s not a solution.
        But not having a substitute isn’t an excuse to continue to pollute. And sometimes you have to accept that the only solution is to go back to a less easy solution, like manually pulling/cutting grass.
        Here in France (probably whole EU too), since some years it’s now fordidden to use weed killer treatment in cities sidewalks or green spaces, which was before very much used because so easy! So now you mostly have to use manual tools to somehow cut or remove grass, and/or accept that you have some grass growing (which by the way is good for insects, so good for birds eating them!).

      1. If they just get buried in the grass and covered by soil as they are almost 100% likely to do? Nothing. The likelihood that they wash into the drain and into the water is very low.

      2. Over time, plastics are fragmenting to more and more small pieces, up to the point it can be ingested by various kind of animals, insects, worms… Microplastics can also penetrate the roots of crops, traveling up the plant into the parts we eat. And once they can get at some stage of food chain, they will propagate through all the chain, and concentrate in organisms, including human ones.
        Also, plastics are not pure: in addition to their main component (nylon for example), they are other chemicals/components included to modify their characterics, and by disseminating plastics in the environment, you also disseminate these chemicals.
        And finally, plastics are not naturally found in the environment, so like other substances, we should simply not disseminate them everywhere.

  6. “proprietary weed whacker string”, isn’t it all just a standard thickness? about 1.75mm, I recall someone did a video at 3d printing with it, which largely worked.

    1. Just bought a decent sized spool of this stuff thinking it looked a lot like 3d-printer filament. Seems super dumb to read that the spool container has ‘patent’ all over it (for such a basic thing), so I guess it’s the part at the business end of a weed wacker. Until I either buy or build a 3d-printer, I’m going to use this hardy string for jamming and twisting into unknown thread holes, to then read with a gauge.

  7. This is really backwards, if you are concerned about disseminating plastic in your garden just buy biodegradeable trimmer line. With this project you are replacing regular trimmer line with a plastic that breaks down even slower.

    1. Except that biodegradable plastics only degrade in industrial composting treatments, at high temperature (between 60°C to 90°C) and good oxygenation, but not in natural environment or with home user composting process. They can fragment into microplastics, some seem to disappear because they can’t be seen with naked eyes, but they stay there for a long time.

      1. Sure, but I bet a “biodegradable” plastic would still break down faster in a garden than a non-biodegradable plastic. Hopefully the biodegradable one would also contain less BPA and other non-degradable plasticisers.

  8. First, in several EU countries, plastic bottles are recycled industrially (you get money back when you take them to the supermarket – like 0.25€ a bottle). Pretty silly idea to use such valuable resources just to cut things (weed AND plastic).
    Second, trimming is for wimps. A good gras is to be eaten by … well, goats, guinea pigs, horses …. or smoked. Obviously.
    Third, yes, it’s a hack. But why not hack a metal solution (read “blade”) instead?

  9. A reader wonders, “What’s so bad about tiny pieces of nylon in the environment”

    This reader wonders, “What’s so bad about a fringe of grass that my (electric) mower can’t reach?” I’ve used my edger maybe twice in 15 years.

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