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Extruding PP from recycled plastic from ocean


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I am extruding PP plastic we got from a company gathering plastic from the ocean. I do not have a datasheet or any other material information. Does anyone have experience with extruding PP? What are good temperature to use?

I was trying it for 2 days with temperatures around 170-180 degrees, but I can't manage to fine tune it to have a consistent thickness.

HDPE from the same company was working very nice.

Thank you for any advice


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Topic starter

I forgot to add pictures: 


Picture 2


Hi Patricia,

Great Idea. Love to know more about where and how the company is collecting. 

It looks like the filament is coming out with a "like" drawn or pulled effect. So it looks like the crsytalisam of the plastic is not homogeneous. 

I was having the same issues with HDPE the other day with Contaminated materials, that I think had other plastics in the shred and not only HDPE. So I would double check if it is only PP. (I have no idea how to check that). Note the comments on "thermal properties". It looks like you're temps are in the right range.  

Just some thoughts, Adrian 


@adrian Thank you for your reply!

Can you please tell me your temps for HDPE?

Currently I am using H1 - 170

H2 - 175

H3 - 180

H4 - 185

Fan 50%

2.0 rpm

But yes, I think you are correct. Plastic is contaminated, even if I just look at the pellets, I can see stripes which I am not sure are just from different color...

I would very much like to extrude filament even though it might be mixture, do you think its possible? It might not be pure PP.

This is the company we are collaborating with:

Thank you!


Hi Patricia, 

For 2mm Rpm 5, H 4- 165, 3-170, 2- 170, 1- 165. Fan at 30% for HDPE.

But if you have seen my other posts, I am still planning to play with the Temps. But it works so far. 

What is your reason for the low RPM? 

You could also try to sort out a few handfuls of pallets from the "striped" ones to the solid green, then only use only one colour to extrude X meters then put in the other colour and see if it has any effects. 




Thank you for your temperatures!

I forgot to write, yes, I am extruding 1,75 mm for 3d printing.

I was lowering rpm because wheels next to the thickness sensor were squeezing it too much = it wasn't cooling down fast enough. When I lowered rpm, it started to work.

It's really good idea with sorting out. But for 3D printing you need very good quality. Today I started mixing 50% of raw PLA granules from 3Devo and 50% of recycled PP, and it's working like charm! Results are a bit transparent from PLA, and it's not purely recycled material, but it's working. I am running it on:

rpm 3.0 H1 170, H2 175, H3 180, H4 170, fan 100%

Dear @patricia and @adrian ,

Thank you both very much for participating in this discussion 😊 
It is always a pleasure to see two friendly users that share a common goal and help each other. 

I will do my best to contribute here.

First, I can say that this guide applies to PP in the same way it does to HDPE. 

There might be several issues in your case : 

  • ovality due to crystallization (see article above). This complementary article (not PP-specific) can help
  • incomplete melting
  • bad texture
  • contamination. Difficult to say, given the color of the base pellets. Running a DSC characterization test would be interesting, but you perhaps do not have access to that technology ?
  • the grade is perhaps just not compatible with this extrusion process. One of the criteria is explained here in a simplified way. Do you have a Technical Datasheet ?
  • non-optimal settings. Most of our articles explain how certain issues are connected to settings adjustments. Unfortunately, most of it comes down to just testing different parameters and trying to observe trends. I can help you with that if you send me a datalog and more pictures/videos  😉 For PP, in general, the thermal window is 160-210°C, and the RPM window is 2.0-6.0. The fancooling depends on your room temperature

I know this can be quite overwhelming. Your material is very tricky, but I am sure we can isolate, understand the issues one by one. If you keep me up to date with your results, I will help you analyze the experiments.

Please let me know if anything is unclear 

Dear @louis


Thank you very much for your thorough answer.

First, I want to apologize for my late reply. I ran out of pellets I was using, and I can't continue with the project until I get new ones.

I am attaching my log from PP testing, I hope it answers some of my problems. I am going to test out circular cooling from your 3D printed fan. As for the contamination and grade of pellets, I can't do anything about them, as I am getting all pellets from another company we are collaborating with. They are recycling plastic from the ocean, so it is far from being industrial grade, and I am pretty sure it is contaminated with other plastic. But I still would like to make it work.That means I can't run DSC test and I don't have datasheet for the material.

It's just try and fail, so I was wondering if someone else used these materials and I could use those temperatures as a starting point.


I will let you know how my tests continues :)



Hi Patricia, 

I meant to ask, are you making this for use in a 3D printer? 


Topic starter

Hi @adrian


Sorry for late reply. Yes, I am making filament for 3D printing. I am testing that now, but finetuning settings for print is becoming tricky. Especially adhesion to the bed. Do you have any experience with this?



Hi Paticia, 

My understanding is that the biggest issue with HDPE, is that the plastic does not stick to it's self. Therefore as you know with FDM printers you need to manage the Print head and Bed temp. When I tried a few months ago I was have heaps of issues. Warping after first few layers was the major problem and the it looked awful. 

I was able to print at 100C bed and slowed down the speed. I also have built a enclosure for ABS, that I don't use for PLA, so I put that on and it seemed to help. 

I found this website that helped me get some reasonable success. Have a read for some new ideas.  

Hope it helps.



Topic starter

Hi Adrian,

I am using Raise3D Pro2 Plus, which is fully enclosed. And right now I am running it at 280C nozzle, 70C for heatbed. After all day of troubleshooting the best for adhesion was packing tape. But at third layer it starts lifting from the bed, warping too much and I can't manage to solve it.

I tried other solution, and made a new filament with 50% HDPE and 50% PLA. It's much stiffer and nicer to work with. But I can't get to second or third layer, as the printer stops extruding, as the filament gets stuck next to drive wheel. I think it must be something with temperature and underextrusion.

Your article helped me a lot! Thanks :D 

Back to the testing...

Have a nice day