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PETG: The Filament You Didn't Know You Needed

A 3D printed filament hanger made from grey PETG. Shown holding two 1kg spools of filament. A 3D Printed filament hanger made out of grey PETG.

Just an example of what PETG is perfect for - strong parts! Shown here is a hanging filament holder that can hold two 1kg spools of filament. Printed in Gunmetal Grey PETG.

PLA has always been the material of choice for the majority of the 3D printing community. It's easy to print, has good mechanical properties and doesn't require an enclosed printer or any other special considerations when using it. ABS is another very popular 3D printing filament, it is stronger than PLA but also releases harmful and bothersome fumes and requires an enclosed printer and high printing temperatures. Layer separation, shrinkage and warping are common problems experienced when printing with ABS.

PETG is a great material that gives the best of both worlds: It doesn't require any specialized printer hardware or modifications and parts printed with it are stronger and more rigid than parts printed with PLA.

With the right slicer settings, any hobbyist-grade 3D printer can print this material just as easily as PLA! Coex 3D PETG is a great way to get started with the material. Our PETG starts with high quality virgin resin and is produced to the highest standard of quality in our manufacturing facility right here in Wisconsin, USA.

What is PETG?

PETG is a thermoplastic like any other used for 3D printing, PET (Polyethylene Terephthalate) is the primary component of PETG, with the "G" standing for Glycol which is added to the mixture to lower the melting point and give other properties that make it an ideal material for 3D printing. PETG tends to perform very differently depending on what brand of filament you use, as each has their own formulation. This can lead to wildly different print results between different brands of what appear to be very similar filament. Coex 3D PETG is manufactured to the highest standard of quality right here in Wisconsin, USA. Using Coex 3D PETG will guarantee consistent results with every print.

Why use PETG?

PETG offers many benefits over PLA for 3D printing parts, especially functional parts - and even some benefits that apply to decorative or cosmetic pieces!

  • PETG has better strength and rigidity than PLA, allowing parts to hold up to tougher loads.
  • PETG is chemical resistant and won't be affected by substances such as isopropyl alcohol or acetone.
  • Parts printed in PETG are watertight.
  • PETG can be used to give thin parts a translucent, glass-like appearance.
  • PETG is easier to sand than PLA. PLA tends to get gummy when sanded due to its low melting point, PETG can be sanded much more easily than PLA.
  • Printing with PETG does not release bothersome and dangerous fumes like ABS does.
  • PETG does not shrink significantly when cooling, which prevents layers from separating during printing and helps maintain dimensional accuracy of printed parts.
  • Any hobbyist grade printer that can print PLA will print PETG just fine! No specialized printer hardware or modifications are required to have success with this material.

How do I print with PETG?

PETG is almost as easy to print as PLA. As with every 3D printing material, there are some specific considerations that need to be made when printing with it.

  • PETG requires slightly higher hotend temperatures than PLA. Common printing temperatures for PETG are in the range of 230-245C.
  • PETG also requires a heated bed, a bed temperature of 75-90C is recommended.
  • Too much cooling can be detrimental when printing with PETG and can cause poor layer adhesion, making prints weak along the Z-axis. Turning down max fan speed to 50-75% and disabling cooling for the first 3-5 layers is recommended.
  • IMPORTANT! PETG can bond to your print surface in some cases. This especially applies when printing on a PEI bed, but PETG can even become firmly fused to glass beds, taking chunks out of the bed along with your part! To avoid this, use Magigoo, glue stick, or painter's tape to help the part release easily from the print bed.
  • PETG is hygroscopic, meaning it absorbs moisture from the air. If the filament absorbs too much moisture, you could experience inconsistent extrusion and excess stringing. We recommend drying PETG at 65C for at least 3 hours prior to printing with it if it has been exposed to humidity. You can use a filament dryer such as the PrintDry Filament Dryer or a food dehydrator. Make sure to store your filament in a dry environment or use a vacuum sealed filament container along with desiccant packets.

Help! My prints are super stringy!

Yes, it is true that PETG is more prone to stringing than PLA. This is a commonly experienced downside of printing with the material. That said, there are steps you can take to reduce stringing when printing with PETG.

Lower the temperature.

The lower the temperature, the less likely stringing is to occur. However, keep in mind that lowering temperature also often reduces layer adhesion. Finding a balance is important when choosing printing temperature.

Increase retraction.

Especially for Bowden tube extruder setups, increased retraction can help reduce stringing.

Enable "Wipe while retracting."

Some slicers have a "Wipe while retracting" option which causes the hotend to start the travel move while the retraction is happening, effectively "wiping off" the nozzle as it starts to move.

Enable "Combing mode" (Cura) Or "Avoid crossing Perimeters" (PrusaSlicer/SuperSlicer).

Normally, travel moves will move from one point to another in a straight line. By enabling this setting in your slicer, travel moves will prefer to stay "inside" the print. This can increase print time slightly, but by avoiding crossing over perimeters, this will help eliminate stringing at the source wherever possible.

These tips can help reduce stringing but it's often not possible to eliminate it entirely. Some post-processing of prints is usually required to remove strings and other blemishes.

Wrapping Up

We hope this has been a thorough and helpful primer for why you should try PETG and how to print with it. PETG provides a great balance between printability and strength, making it a great step up from PLA without the printing challenges presented by ABS. Check out all of the Coex 3D PETG options for high quality PETG in stunning colors - and don't forget to subscribe to our newsletter to get 15% off your first order!

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