How to Use Recycled PET Plastic as 3D Print Filament

(source: Pexels)

What if your next 3D print could save the planet a little? That’s not just greenwashing, it’s a reality many makers are turning into a habit. With the right tools, knowledge, and a few bottles of soda, you can turn used PET plastic into high-quality, printable filament. Yes, that PET (polyethylene terephthalate), the same material used in your fizzy drink bottles, blister packaging, and dozens of other consumer goods.

Recycling PET into filament isn’t just a cool eco-conscious flex, it’s an opportunity to cut costs, reduce waste, and deepen your understanding of the materials behind your prints. Whether you’re a hobbyist or small business, 3D printing with PET plastic is becoming a viable and rewarding path.

Why PET? Why Now?

PET 3D printing has been gaining traction for good reason. PET (and especially its modified version, PETG) strikes a rare balance: it’s strong, impact-resistant, and food-safe, yet easier to print than materials like ABS. And now, with growing access to recycling tech, we're no longer limited to buying virgin PET filament, we can make it ourselves.

Using PET plastic for 3D printing not only extends the life of single-use items but also offers a reliable material that’s well-suited for functional parts, containers, wearables, and more. It's tough, slightly flexible, and holds up to repeated stress.

Want more useful tips once you've got your filament ready? Check out our blog on Top 3D Printing Tips to Fix Quality Issues & Improve Every Print, you might just find your next saviour.

(Source: Reddit)

Step-by-Step: How to Turn PET Waste into Filament

1. Collect Clean PET Plastic

Not all PET is created equal. Stick to water and soda bottles, which are almost always PET and easy to clean. Avoid labels with adhesives and multilayer containers. Thoroughly wash and dry each piece, you don’t want moisture or contaminants in your final filament.

2. Shred It Down

Use a plastic shredder to cut the bottles into small flakes. Consistent sizing helps during extrusion. If you don’t own one, there are open-source designs for DIY PET shredders online.

3. Dry the Flakes

PET is hygroscopic, meaning it absorbs moisture from the air. This leads to bubbling and weak prints. Dry the flakes at 70–80°C for several hours in a filament dryer or an oven with precise temperature control.

4. Extrude Your Filament

Using a filament extruder like the Filabot or Felfil Evo, feed in your dry flakes and tune your heat settings, around 240–270°C. Consistency is everything, so ensure constant speed and cooling during extrusion. The goal? A clean 1.75 mm or 2.85 mm filament.

5. Spool and Store

As the filament cools, guide it onto a spool using a winder setup. Store the finished PET filament in a dry box to avoid moisture reabsorption.

Best Practices for 3D Printing with Recycled PET

● Print temperature: 240–260°C

● Bed temperature: 60–80°C with glue stick or PEI sheet for adhesion

● Cooling: Moderate fan for overhangs

● Dry filament before use: Every time

Your prints won’t just look good, they’ll hold up to wear and tear. PET 3D printing is known for delivering watertight parts with just a few passes of tuning.

Thinking Bigger

Recycled PET filament for 3D printing opens doors beyond just personal use. Startups and sustainable brands are using it to create eco-friendly products: phone stands, planter pots, even sunglasses. Schools and makerspaces are also tapping into it for STEM education, teaching students how to build circular supply chains from waste to product.

If you’re not quite ready to do your own printing or want FDM, SLA or SLM 3D printing without the learning curve, we’ve got you covered. JLC3DP’s 3D printing services include many material options, just send us your files, and we’ll handle the rest. Whether it’s a prototype or a polished product, we print with precision and responsibility.

Challenges You Should Know About

● Color inconsistency: Most recycled PET filament is a natural or cloudy color unless colorants are added.

● Impurities: DIY recycling introduces a higher chance of contamination, use filters when extruding.

● Brittleness: Improper drying or extrusion can lead to brittle, unusable filament.

That said, a bit of trial and error can yield impressive results. Communities like Reddit’s r/3Dprinting and forums like RepRap have a wealth of tips and support.

Should You Switch to Recycled PET?

If you’re printing regularly and want to reduce costs and waste, the answer is a confident yes. Even if you’re not ready to go fully DIY, understanding how PET plastic 3D printing works puts you ahead of the curve. You’ll think more critically about your material choices, and maybe even start turning trash into tools.