Description: This article contains some of the most frequently asked questions about PETG filament in Summer 2019.

Q: What is PETG filament?
A: PETG (Polyethylene Terephthalate Glycol) is a variation of PET with the addition of glycol-modified. Like PET it is a very tough material that prints without odor. It offers durability and impact resistance that is superior to PET. The addition of glycol allows the filament to reduce shrinkage, warping, and increase strength without becoming brittle.

Q: Why would I use PETG filament?
A: PETG is strong, flexible, and recyclable. It is not brittle, will not warp, will not shrink, and can be printed on glass with no glues. It does not absorb water or moisture from the air. Overall it simply has better qualities than PET.

Q: Why wouldn’t I use PETG filament?
A: It is difficult to use as it requires fine-tuning of the bed and nozzle temperature. It can produce hairs on the surface due to stringing and has poor bridging characteristics.

Q: What temperatures do I print PETG filament at?
A: While the exact temperature will vary based on your printer, the filament you are using, and your preferences, the recommended range of temperature for PETG filament is 220-245°C, and 70-75°C for the bed temperature. You are not required to use a heated bed if you are using glass; however, it does make the process much easier.

Q: What sizes of filament do I need?
A: The size of filament that you need will vary based on your printer. Currently there are 1.75mm and 2.85mm filaments available. Usually printers will only support one of these sizes, so ensure you are using the correct size.

Q: Why is there 3.0mm filament listed online?
A: 3.0mm filament is another name for 2.85mm filament. It was originally used as an easier way to purchase filament, rather than using a rather specific number of 2.85mm. However, over time some manufacturers did not realize this and started making 3.0mm filament, so be sure to check the size in the specifications for the filament. This will normally be listed as true diameter and should be listed as 2.85mm rather than 3.0mm. 1.75mm filament however does not have this issue, and you can purchase it without any inconveniences.

Q: What print speed should I use when printing with PETG filament?
A: The exact speed will vary based on your printer and your personal preference, however typically 30mm/s - 40mm/s is the recommended print speed.

Q: What retraction settings should I use?
A: Retraction settings (speed and length) will vary greatly based upon your printer, what type of extruder you are using, and what filament you are using. To fine tune this based on your printer, you can follow this guide: https://www.matterhackers.com/articles/retraction-just-say-no-to-oozing.