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Making lumber with recycled plastic

This topic contains 4 replies, has 5 voices, and was last updated by  SeanZ 4 years ago.

Mike Harmon parseraider

Making lumber with recycled plastic

26/09/2015 at 08:48

I see everyone talking about making filimant for 3d printers. ANd the problem is keeping the light tolerance on diameter.
Maybe concentrate on weedeater string would help create a little backyard money for communitys.

My real question is when recycling plastic for making lumber or non food usage large items, is it possible to use all types of plastic at one time and be able to extrude it?

WOuld some types burn before others melted? I am thinking that you would have less tiem in sorting and be able to use it all to make non structural or load bearing items.

I think that a person could estimate per batch the amount of grade1 , grade 2 etc and maybe add more HPDE to keep brittleness down while getting rid of those water bottles.?????

I am totally new to this but I am going to be very soon releasing a KickStart project that involves injection molded parts and naturally looked into making my own parts and am amazed at what plastic can do.


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29/09/2015 at 08:08

Hi Mike,

indeed a lot of talking about printer filament, I think 90% is still working with PLA, because printing real plastics is major league. Making and use recycled plastic filament is still for the real die-hards :). But someone has to start with it…

Mixing plastics will work for injectionmolding, but something to consider, is it’s not recycable anymore.


03/05/2016 at 15:08

And not all plastics are compatible between them. My suggestion is to keep sorting and work with the same polymer as much as possible.
Wood composites exist in blends, around 20% to 50% wood powder with HDPE.

I wouldn’t know how you could work that on the machines made available through this website and am commenting on what can be done based on my experience

03/05/2016 at 18:15

@ keesdeligt even better would be to feed a printer with pallets and skip the filament phase.
This could save 25% or more printing energy?

50Watts of power to re-melt the filament.

Then I wonder how plastic ‘lumber’ would compare to real lumber. When it is being used. How long does it last. And impact on the environment after that.

What plastic types would make most sense?

15/09/2016 at 09:16


I was at a ferry pier the other day and realized that the entire structure of the pier coverage was made of lumber like plastic. I would suggest recycled plastic as the texture is a big rough, key seems to be in over-dimensioning the parts in order to have a long term resistance. But… to do this you require major power and heavy industrial equipment. The plastic needs to be injected rapidly enough to fill in the mold cavity without cold spots. I would also suggest that fiberglass filling compound quickly comes into question to strengthen the material, which makes the operation even more energy consuming and extra machinery/operation to get the right mix. You would want to probably stick to poly-carbonate reference code “7” like computer screen backs/tv to do this.
Do anyone have any experience in big full chunks of HDPE or maybe PP?

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