It’s occurred to me that probably about 20% of the PLA is scrap either from supports or failed prints and while I toss in the recycle bin (because the city says all plastic must go there) I can’t imagine that the people at the recycling facility do anything with random plastic scrap… so I’m wonder is it possible if you had the tools, to melt the scrap PLA and re-extrude it into fiber or does it undergo some kind of chemical state change as a result of the heating and extruding?
It’s perfectly possible to create your own filament. Google for pellet extruder and you will find commercial solutions/devices that can do it.
It is also possible to build a diy solution.
Then you just need to grind your scraps to small enough parts for this use case.
But you will probably find very quickly that it’s probably not going to be very cost effective. 1000usd for the device, a lot of time to prepare the plastic and the actual extrusion and filament with subpar specs. Quality of the plastic will be good, but the diameter will vary a lot more than when you buy a roll. And if you mix different colors you always end up with brown-green filament.
When I looked into this a while back, I discovered it’s also possible to recycle it into slab material, which you can then use for the same kinds of things you would do with a similar-sized piece of wood. (I’ve even heard of people doing machining/CNC with it, although I’d want to know more than I do now about cutting plastics that way in general before I tried.)
This is much cheaper and lower-tech than producing filament with it (required: sledgehammer for smashing up larger pieces of PLA, oven/toaster oven to soften it, two metal pans to use as a mold, rocks or bricks to weight the top pan and squish the plastic down so that it conforms to the mold), but may be less useful.
Most stuff I’ve read indicates that putting PLA in the recycling bin isn’t great. It’s not marked with a recycling symbol, so it’ll either get tossed with trash, or mixed in with other kinds of plastics.
I’ve been saving my waste PLA. Once I get enough of it, I’m going to call my local hazardous/e-waste disposal facility and ask if they know what to do with it.
Supposedly you can compost it at home, but it’s not the best. Most articles I’ve read say home composting usually ends up with small plastic bits mixed in that take years to fully break down. Maybe if you grind it up into relatively small pieces first, but I haven’t tried it.
Thanks for the suggestions, @brvdboss I’m not so concerned about cost effectiveness so much as just reducing the stuff that goes to the landfill, if I can produce serviceable filament for less than an arm and a leg I may try that or I may just go with @ElloryJaye 's suggestion and melt it down into blocks that I can use for random stuff around house (paperweight/doorstops anyone?) or see how they CNC.
I don’t see composting working for me, too many critters get into my “so called” compost piles.
There do exist some recycling programs that collect filament & scraps for recycling. Sometimes if you have a makerspace in your neighborhood they also collect it and donate it to a recycling program. I once even read about a filament producer that allowed you to ship back scrap material back in the box your new role came in. (can’t find the link anymore, don’t know if they still exist or do it)
But I like the suggestion from @ElloryJaye the best as well
Here’s some miscellaneous links from Instructables about this that I remember hitting a year ago (with pictures of objects produced with the toaster oven type of recycling):
(I think the information about machining recycled plastics was mostly about HDPE rather than PLA, now that I’ve reinvestigated, but that just means no one’s tried PLA and posted the results.)
Good stuff there, thanks for the links. I’ll have to give those a try