PETG: the PLA Filament Alternative that Just Works

A typical response to the previous article on why PLA filament is so darn brittle. This has led some people to not use PLA filament at all, while others promote …. PETG: the PLA Filament Alternative that Just Works.

This has led some people to not use PLA filament at all, while others promote using PLA only for prototyping and throw-away parts, especially in light of PLA being compostable under the right conditions. For many mechanical parts, people turn to PETG. Much like the PET polymer used for everything from food containers to drink bottles, PETG is durable, more resistant to degradation through mechanisms like hydrolysis and its filament form doesn’t need to be coddled like PLA does.

PETG, on the other hand, tends to come from crude oil and shrugs at industrial composting conditions. In terms of durability, degradation mechanisms and recyclability, is PETG the basic FDM filament which we should all just be using. Polyethylene Terephthalate PET (backbone: C 10 H 8 O 4) is a polyester, just like PLA (backbone: C 3 H 4 O 2).

Due to how common PET is in both packaging and textile applications it’s usually just called “polyester” when used for textiles, where it is often blended with cotton and other fibers.