Composting PLA

Bambu and other manufacturers tout their biodegradable PLA. But it isn’t normally. Can’t even put it in with recyclable plastic, as it is an “Other” so will go right to landfill. Now that I have had my A1 a few months, that is starting to really “chap my hide” as some old cowboy actor said once. Most of what I see on the internet is suggestions to make your own filament from waste filament. I am not a fan, as the 2 reels of recycled PLA filament I bought were very disappointing (from different manufacturers who know a lot more than me about making it!). One never stuck to itself at all. The other needed high temps but did print successfully. However, when I left it in my 10% humidity AMS Lite enclosure for 2 weeks, then it was brittle and continually broke, wouldn’t feed again.

I propose figuring out how to make composting PLA work, at a reasonable cost. The 3D printing community is smart enough to take this on I think. I don’t think a failed big print is going to compost at home. But if it is shredded to fine mulch size particles, then, probably, with a little warmer compost than usual.

For my part, I will start by getting a branch chipper. They cost about as much as a Terracycle ZeroWaste Box, that you send your PLA off to them to recycle in ($181 for their smallest box as of today). The one I found is on Amazon at Amazon.com : Earthwise GS70015 15-Amp Garden Corded Electric Chipper, Collection Bin : Tools & Home Improvement

Then, will have to figure out safe way to “warm compost” the plastic chips. I am open for suggestions, and will post what I find that works or does not work.

Let’s make the “biodegradable” “compostable” true!

Before getting rid, you could always try reuse.

Many have tried the idea of chilly and grinding down to then try making their own filament spools from the material left over.

This has quickly gone from home grown to commercial gear to do the job for you.

You could also repurpose p, some have used flat heaters to form sheets that they then use with CNC machines to make all manner of things like the seats for chairs and far more.

I agree with reusing. Which I think composting is. I also want to stop burning branches and weed vines every year, and instead chip and compost them. Our compost gets used in our vegetable garden and flower beds. So being able to chip branches and brush, and throw the PLA into that stream also, would be better for our CO2 impact, and reusing in our own yard. And far more realistic than thinking sometime I might use it otherwise. I am just not motivated enough to do all the other Maker things that would re-use, though they sound like good projects.

I figure I will need a metal container to do warm composting in. My first run will probably be with a metal trash can or an old crude oil barrel that I drill holes in for aeration, and with a couple barbecue smoker grills across the bottom to hold the compost up while allowing some air in. And check temperature every so often with a long meat thermometer. Of course it can’t be our regular compost, because warm compost and kitchen food waste would probably smell like catfish bait! And attract critters. But the only concern with warm plant waste compost would be fire, so I’ll probably put the warm compost barrel out by our vegetable garden, with nothing around it to catch fire if it burns. Which would be kind of funny, as then doubling as a burn barrel! :joy:

PLA degrades into CO2 and water, so composting it to then feed to plants makes zero sense. You might as well just burn it. And if you care about carbon footprint (I assume it’s about CO2) then, assuming there is a good amount of carbon in the first place, leaving it be in plastic form is actually better. I suspect the real damage is done during production though, because of the energy needed to produce the plastic.

Then, there are additives, about which we know exactly nothing. We know that PLA filament is generally non-toxic, but that’s it. What happens to the additives when they get transformed by composting or burning or whatever - get a chemical lab and find out, for each filament manufacturer and for each color and so on. Maybe it will poison you if you put it in your garden, maybe not.

Just accept that you produce plastic waste that goes into landfill. If that’s not good enough, then work to make filament producers make stuff that is compostable or whatever it is you want to do with it. But otherwise it’s just wishful thinking - “PLA is biodegradable” is meaningless in itself, the devil is in details, as always.

[EDIT] Recycle/reuse is good stuff. The above only applies to landfill vs composting.

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PHA could be good filament in the future. It is home compostable.

The degradation rate of pla material is determined by the environment, and it takes about half a year to two years, so if it is fast, it should be okay to burn it.