Video summary

PET Bottle Recycling: Waste to 3D Printing Filament

Main summary

Key takeaways

Product Review

Product reviewed

A DIY “Recreator3D” machine built from a salvaged, decommissioned Ender 3 (using pultrusion) to turn PET bottles into 1.75 mm 3D-printing filament for use in standard printers.

Main features / how it works

  • Pultrusion-based filament making

    • Cuts a PET bottle into a long strip.
    • Softens the strip in a modified hotend (PET is not fully melted).
    • Pulls the strip through a heated nozzle to form consistent filament.

  • Filament size

    • Targets 1.75 mm
    • Achieved via a modified nozzle/orifice expanded from ~0.4 mm nozzle stock.

  • Machine construction

    • Salvages an Ender 3 hotend, plus frame parts and components.
    • Uses an oversized 24V PSU (one small heater + stepper motor).
    • Includes a bottle cutter module (Joshua’s design; uses bearings to shear/cut).
    • Uses a winder driven by a stepper motor with gearing/reduction.

  • Firmware

    • No special firmware required; uses existing printer/control board parts.

Setup / user experience notes

  • Build complexity

    • “Not totally sufficient” out of the box even with salvaged parts.
    • Missing fasteners require sourcing (e.g., M4x8 screws and T-nuts).

  • Printing/enclosure effort

    • Enclosure parts took about 1.5 spools and ~2 days of continuous printing.
    • Mentioned printers: X1s, Prusa MK4, Snapmaker J1S.

  • Operating flow

    1. Thoroughly clean/rinse bottles (labels/glue must be removed; sticky residue can clog the system).
    2. Reduce beading/creases (hot air gun + internal pressure technique).
    3. Thread the strip into the hotend and start—then the process runs in the background.

  • Speed

    • Conversion is slow: a large bottle takes about 2 hours.

  • Starter experience

    • Satisfying first pulls: watching the strip form and spool as it’s drawn through the nozzle.

Filament properties & printing guidance

  • Temperature behavior

    • PET is not melted at working temps.
    • Nozzle set around 210°C, below PET melting point.

  • Filament structure

    • The process folds the strip into a hollow-tube-like filament.
    • The interior remains slightly hollow.

  • Slicer settings

    • Compensates for hollow filament by increasing flow.
    • Reported working value: ~130% flow
    • Reduced max flow rate to about 4 mm³/s for stability.

  • Printer compatibility

    • Printers should be able to reach 250–260°C nozzle.

  • Adhesion example

    • Printed successfully on Prusa Silk PEI with a 80°C bed, with few adhesion issues.

  • Comparative context

    • The hollow/flow adjustment helps explain why some commercial PET filaments use glycol-modified PETG for improved flow.
    • Bottle PET itself is described as “remarkably well” printable.

Yield / cost realism

  • Yield test (example bottle)

    • Bottle input weight: 80 g
    • Filament produced: ~31 g
    • Yield: ~39% (not fantastic)

  • Where losses happen

    • Top threaded bottle parts and other unusable sections.
    • Yield varies with bottle type and size.

  • Economics (Germany)

    • With Germany’s 98.5% PET deposit return rate, it may not be economical.
    • The biggest potential is where PET bottles are abundant waste and filament/material access is limited.

Strength / performance testing (numerical results)

Tensile testing was done on 3 samples per material using a DIY universal testing machine.

Measured tensile/failure stress (MPa, average):

  • ASA: 43 MPa (lowest; yielded then broke)
  • PETG: 45 MPa
  • PLA: 51 MPa
  • As-printed bottle PET: 53 MPa
  • Prusa PC Blend: 59 MPa
  • Annealed / crystallized PET (opaque white sample): 72 MPa (strongest by far)

Key takeaway: As-printed bottle PET is strong enough for practical parts (not just decorative items), and annealing significantly boosts strength and thermal resistance.

Pros (as stated/indicated)

  • Creates usable PET filament at home via a simple concept (hot nozzle with a hole).
  • Good printing performance with proper flow compensation.
  • Positioned as real recycling into functional parts (not “downcycling”).
  • Promising strength: 53 MPa average as-printed; 72 MPa after annealing.
  • Community-driven: multiple upgrades/design variants exist.

Cons / limitations

  • Low yield: ~39% in one test (varies by bottle).
  • Slow process: about 2 hours for a large bottle.
  • Demanding preprocessing
    • Cleaning and label/glue removal (acetone used; other removers suggested)
    • Beading/crease smoothing required
  • Material variability
    • Bottle brand/type differences create uncertainty (including possible fumes/emissions concerns if unintended for printing).
  • Not mainly cost-saving in regions like Germany with strong deposit return systems.
  • Requires tinkering/modification (nozzle drilling/orifice sizing, cutter build adjustments, sourcing missing parts).

Comparisons made

  • Machine designs

    • “Straightforward online machines” often draw plastic strip through a hotend + motor, but require manual strip cutting and spool winding.
    • This build salvages Ender 3 parts and follows a pultrusion community approach (MK5 kit concept) plus a custom Recreator3D layout.

  • Materials for strength comparison

    • ASA vs PETG vs PLA vs Prusa PC Blend vs bottle PET vs annealed bottle PET
    • Annealing/crystallization greatly improves strength and thermal resistance.

Unique points mentioned (distilled list)

  • DIY pultrusion machine converting PET bottles into 1.75 mm filament
  • Claims it’s an easy and “most consistent” home filament-making method
  • PET bottles as both problem and opportunity
  • Pultrusion steps: cut into strip → pull through hot nozzle
  • Based on salvaged Ender 3 parts and Joshua Tailor/JRT3D designs
  • Parts printing approach:
    • Mostly PLA
    • Some parts in PETG (requires hotter hotend mount + gears)
  • Enclosure parts required significant time/material (1.5 spools, ~2 days)
  • Salvaged/reused:
    • Hotend, LCD/control components, Z-axis aluminum extrusion frame, power supply
  • Bottle cutter:
    • Bearing-based shear/cut concept
    • Adapted for Germany (cent-sized alternative printed)
  • Hotend modification:
    • Enlarges nozzle orifice to ~1.7 mm using a drill bit
    • Uses countersink due to lack of stepless drill bits
    • Modified heater/heatsink transition improves uniform softening
  • Reassembly leaves a designed gap to keep a longer section warm
  • Operation:
    • Set hotend to 210°C
    • Pull/prime with pliers, feed to spool
    • Joshua provided a file to run the motor for initial feeding
  • Process time: ~2 hours for a large bottle
  • Hollow filament behavior due to softening (not melting)
  • Printing requirements:
    • Printers able to reach 250–260°C
    • ~130% flow
    • Max flow reduced to 4 mm³/s
    • Example bed: Prusa Silk PEI at 80°C
  • Yield: 80 g bottle → ~31 g filament → ~39%
  • Economics: Germany deposit returns (98.5%) reduce appeal; exceptions exist where deposit systems don’t apply
  • Bottle prep:
    • Rinse thoroughly (water vs Coke example mentioned)
    • Remove label (hot air gun + solvent; acetone used)
    • Remove glue residue to prevent clogging
    • Remove beading/creases (hot air + internal pressure rotation)
    • Cut off bottom (safety note for box cutter)
  • Strength testing averages (MPa): ASA 43, PETG 45, PLA 51, bottle PET 53, Prusa PC 59, annealed PET 72
  • Positioning:
    • Not downcycling
    • Suitable for practical parts and tools/repairs/education/prosthetics
    • Best in regions without affordable filament supply

Speakers / contributors

  • Main speaker (Stefan, CNC Kitchen): presents the build, operation, preprocessing, yield, printing guidance, and strength testing results.
  • Joshua Tailor (JRT3D): promotes PET pulling and contributed the pultrusion/machine design approach (MK5 kit concept) and earlier sample filament samples; this build adapts his cutter/design.

Concise verdict / recommendation

Strong DIY-capable recycling project: as-built bottle PET filament can print well and shows good tensile strength (53 MPa average), with much higher strength (72 MPa) after annealing. However, it’s slow, yield-limited (~39%), and requires considerable bottle prep + tuning.

Best for hobbyists/education or regions lacking filament supplies; less compelling purely for cost savings in places like Germany with high PET deposit return rates.

Original video