Filament Maker:
Preparing the Bottle

Recycled PET is a versatile material, but it has some unique properties that affect what you can successfully print. While it offers good durability and resistance to moisture, it is not ideal for very thin or highly detailed parts that require strong layer bonding.

What works well:

✅ Functional parts – Brackets, tool holders, storage containers, and similar items that don’t rely on extreme thinness.
✅ Structural components – PET has good stiffness, so larger, solid parts perform well.
✅ Water-resistant objects – PET’s low moisture absorption makes it ideal for outdoor items, bottle adapters, and utility clips.
✅ Experimentation & prototyping – PET is a great material for testing designs that don’t need extreme strength across the layer lines.

What to avoid:

❌ Thin-walled or intricate models – PET does not bond as strongly between layers as some other materials (e.g., ABS or nylon), making slim parts prone to splitting under stress.
❌ High-detail miniatures – Fine details may not print well, and small unsupported sections can be fragile.
❌ Load-bearing parts under bending force – PET is strong when printed flat, but parts that rely on strength across the layer lines can be weak.

Tips for Success:

• Increase infill – A higher infill percentage can improve part strength.

• Use rounded, thicker designs – Avoid sharp corners and extremely thin features to reduce weak points.

• Print orientation matters – Try to orient parts so that forces act along the printed layers, not across them.

The best way to learn what works is to experiment! PET is a fantastic material when used correctly, so test different designs and print settings to find what works best for your needs.

If you’re experiencing issues with print quality or filament not extruding properly, follow this checklist to troubleshoot:

• Correct strip size: Ensure the PET bottle strips are the right width for your bottle thickness. As a general guide:

  • 10mm strip for 0.1mm bottle thickness

  • 9mm strip for 0.2mm bottle thickness

  • 8mm strip for 0.3mm bottle thickness

• Filament shape: The extruded filament should form a consistent tube shape, not a “C” shape. Adjusting strip width or extrusion settings can help correct this.

• Filament diameter: Measure the filament near the spool (after cooling) to ensure it is within 1.65mm–1.85mm (ideally as close to 1.75mm as possible). Fine-tuning the strip size will improve consistency.

• Print settings: Default PETG settings may not work well with recycled PET. Ensure you're using our recommended print settings for optimal results.

• Cleanliness: Any residue from bottle labels or adhesives can cause blockages and poor extrusion. Make sure bottles are fully cleaned before processing.

This is usually caused by moisture absorption, as PET is highly hygroscopic (absorbs water from the air). To ensure high-quality prints:

• Dry your filament before printing: We recommend using a dehydrator or filament dryer.

• Drying time and temperature: Minimum of 2 hours at 65°C, though longer drying times may be required depending on humidity levels and filament quantity.

• Proper storage: Keep filament in an airtight container with desiccant when not in use to prevent reabsorption of moisture.