Need to grind your plastic down for an exruder?

There are a few filament extruders making the scene and I'd guess that soon we will all own one. The problem is how do you get your scrap plastic down to the size of pellets? Most of the homebrew extruders I've seen don't include a good way to reduce that box of plastic to small pieces.

Here is one way, Liquid Nitrogen and a blender. It's as brilliant as it is radical. Only problem, where do you get it, how do you handle it safely and how much does it cost. There's always a hitch...?

Use Liquid Nitrogen to reduce your plastic.

I'm seeing the pellets being sold for about $4/kg. It just doesn't make sense to go through all of the trouble to grind down your used plastics when you'll spend much more in resources, time, and effort. Not to mention that you'd have to take into consideration contaminants. The filament being produced would also be much lower in quality and durability. I know people are saving their failed prints for this purpose, but I would personally just toss the scrap plastics in the recycling bin.

I'm glad you are responsible and use a recycling bin.

For some people it is the fun of the challenge instead of a headache. I've saved a lot of plastic and I'd like to extrude my own. First of all, I think it's super responsible (as opposed to "regular" responsible) and secondly, it will be fun to tinker with the apparatus. To be honest, I for one can't tell you that I'm 100% confident that what I put in the recycle bin get's properly reprocessed or recycled. I suspect that while the "Curb Pickup" task gets a lot of public kudos, the actual recycling may be very deficient. No one sees that facility/process so they assume it's all properly sorted and none is buried. I live in a large metro area and I'm dubious.

There are various recipes/opinions for how much virgin plastic material needs to be added to scrap to keep it's properties up to par. I do think that someone will create an extruder/grinder combo that will be desktop and can be plugged in like a large coffee maker (they'll become millionaires). You just fill the top bin and come back to a wound spool. That's inevitable if "every household in the country" is poised to have a 3d printer like the prognosticators like to say.

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Originally Posted by RobH2

I'm glad you are responsible and use a recycling bin.

For some people it is the fun of the challenge instead of a headache. I've saved a lot of plastic and I'd like to extrude my own. First of all, I think it's super responsible (as opposed to "regular" responsible) and secondly, it will be fun to tinker with the apparatus. To be honest, I for one can't tell you that I'm 100% confident that what I put in the recycle bin get's properly reprocessed or recycled. I suspect that while the "Curb Pickup" task gets a lot of public kudos, the actual recycling may be very deficient. No one sees that facility/process so they assume it's all properly sorted and none is buried. I live in a large metro area and I'm dubious.

There are various recipes/opinions for how much virgin plastic material needs to be added to scrap to keep it's properties up to par. I do think that someone will create an extruder/grinder combo that will be desktop and can be plugged in like a large coffee maker (they'll become millionaires). You just fill the top bin and come back to a wound spool. That's inevitable if "every household in the country" is poised to have a 3d printer like the prognosticators like to say.

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Well, I can see the hobbiest aspect of it, definitely. I have tubs full of broken and torn down electronics for times when I just need that spare SMD resistor that would have cost me all of $0.01... there's something inherently rewarding to reusing old parts. Though, since I had developed a back problem about 4 years ago, I'm now more about convenience.

As for the recycling industry, I'm not too skeptical. I live in a large metro area as well (Los Angeles and Riverside, CA)... I've seen them process materials, and they do a pretty good job of it.

I can understand the convenience issue. And I have a few friends with back problems and I know it can really slow you down sometimes. I hope yours is not to limiting.

Glad to hear that LA is a good recycler. We expect that from CA though. Every product I own has a sticker that says that California considers it to have carcinogenic materials it it....lol... You have managed to stimulate me to look into Baltimore's recycling efficiency a bit more.

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Originally Posted by atoff

... there's something inherently rewarding to reusing old parts.

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I have to agree with that.

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Originally Posted by Davo

I have to agree with that.

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I third that. I just wish that some of the filament makers could somehow formulate a filament that uses recycled material. It could effectly be cheap and desirable to purchase.

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Originally Posted by intohim

I third that. I just wish that some of the filament makers could somehow formulate a filament that uses recycled material. It could effectly be cheap and desirable to purchase.

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Are you sure that isn't already happening? I have no idea but assumed that many of them mixed in a small amount of reprocessed scrap. I have no knowledge either way and am just asking. From what I understand if you are extruding your own filament you need to use a little bit of virgin filament so that yours has good properties. I don't know how much virgin you add to get it to the specs of purely virgin filament, but would like to if anyone knows.

Just save all your PLA scraps and soften them up with Acetone..............