I recently got a 3D printer and have been experimenting with it a lot, resulting in a lot of failed prints (as well as successes, fortunately).

I'd like to, if possible, find a way to reuse the material from these failed prints. I am thinking about two methods:

  1. The obvious thing to do with the material is to chuck it in an old toaster oven and reuse it for injection molding. Is this something that is reasonably easy to do? If so, what temperature would be reasonable to use? What materials would be good to use for the mold? (off the top of my head, silicone or printed ABS with some kind of sealant seem the most promising)
  2. Are there other ways to easily reuse the material? I've noticed that when PLA is heated to somewhere around 50-60 degrees C (120-150 F) it becomes somewhat soft and malleable. Does anyone have experience molding hot PLA?


To be clear, I'm specifically asking about ways to reuse scrap PLA material, not just leftover filament, and not ways to turn it back into filament or to just recycle it. I'm particularly interested in the viability of the two methods I suggested, and if anyone has experience (positive or negative) with either I'd like to hear about it.


3 Answers 3


Here is a great article on the subject, How to make your own filament by recycling old 3D prints | Part 1.

At $20/kg for new material, it is going to be hard for recycling to break even; but, if the cost is not your concern, there are some options.

Here is another creative option that I just saw... Cue amazing electric guitar riff:

Angus Young - ACDC

  • Guitar Picks (and jewelry)

Here is the video: Failed Print Recycling Revisited // Guitar Picks, Earrings, and More.

  • $\begingroup$ A nice answer, but doesn't quite address what I'm looking for. I don't want to turn the waste PLA back into filament, I'm looking for other ways to reuse it. Thank you for the interesting links regardless! $\endgroup$
    – P...
    Commented May 15, 2017 at 19:39
  • 4
    $\begingroup$ I thought I covered both options - making filament and reusing scraps (be they filaments or parts scraps) by melting them into flat plates and them cutting them into jewelry or guitar picks. IMHO, re-using PLA (unless you are talking LARGE quantities) will always require time and money (it will never be free). Whatever solution will require a lot of passion regarding not throwing the scraps in the trash to justify the time and cost to re-use your PLA scraps. $\endgroup$ Commented May 15, 2017 at 22:58
  • $\begingroup$ That's part of what I wanted to address with my particular suggestions. While flat jewelry and guitar picks are easy to 3D print or make by other means, injection molding and hand sculpting can make things that are difficult or impossible to 3D print. I admit to not paying enough attention to the guitar picks link- it goes into more detail than I realized! $\endgroup$
    – P...
    Commented May 16, 2017 at 20:43

I ended up buying a little handheld 3D pen. It comes in handy when printing models that require assembly. You can use the leftover filament in the 3D pen. If you don't have a 3D pen, you can use a soldering iron (as long as you can control the temp) to weld items together. I works well for part repairs and assembly.

The 3D pens is also handy for quick simple prints, as mentioned above. A guitar pick is a good idea and very easy to make with the 3D pen.

As for making your own filament, there are a couple of machines I would recommend looking into.

First you will need something to prep the material. This shredder will help.

To make your own filament, here are a couple of options

  1. DIY
  2. Off the shelf

Regarding Injection Molding, I have never done it, however found some good info on molding PLA.

  • $\begingroup$ A nice suggestion! Doesn't quite get at the heart of what I meant to ask, but a very good idea nonetheless. Regarding the soldering iron idea, what temperature would you recommend using? I do not have a decent soldering iron at the moment, but am in the market for one and this would be a good secondary use for it. $\endgroup$
    – P...
    Commented May 15, 2017 at 19:41
  • 1
    $\begingroup$ Your right, Sorry P. I updated my response for you. $\endgroup$
    – Brad
    Commented May 16, 2017 at 2:39
  • $\begingroup$ Thank you very much for the updated response! The links were very interesting, and the last one in particular (while obviously more specialized than I may be able to use) is exactly the kind of thing I'd been trying and failing to find before asking this question. My Google-Fu is weak, I'm afraid... $\endgroup$
    – P...
    Commented May 16, 2017 at 20:46
  • $\begingroup$ hey P, I created a video here on getting the most out of Google. That should help you search Google a bit more.youtube.com/… $\endgroup$
    – Brad
    Commented May 17, 2017 at 1:51

https://preciousplastic.com/ Is a fantastic project that promotes plastic recycling into useful objects. They offer free blueprints, videos on how to build the recycling equipment, and offer suggestions on what to make of your recycled goods.

Personally, I am looking into making garden bricks or paver stones. I have not found the ideal temperatures or heating methods just yet.


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