The average 3D printer owner knows a few types of filaments – PLA, ABS, somewhere in the middle, PETG.  PCTG is another option that can be confusingly similar to PETG. Recently, [Igor Gaspar] of [My Tech Fun] took a poke at both types. He obtained both PETG and PCTG transparent filaments from the same manufacturer to compare them directly.

As we recently detailed in an article on PET polyesters, PETG is glycol-modified PET, meaning that some of the glycol monomers are replaced by CHDM monomers to create a more flexible and robust material. PCTG is very similar to PETG, except that more than half of the glycol monomers are replaced rather than less than half. This creates a PET-type material that has distinct physical properties from PETG, which might be desirable for some applications.

PCTG is more ductile due to the addition of more CHDM, but also requires higher temperatures to print, closer to ASA presets. During testing, it’s obvious that PCTG is indeed much more flexible, making it potentially a good choice for springs and compliant mechanisms. PCTG is also highly impact-resistant, unlike PETG, and resists higher temperatures much better.

Overall, other than the higher printing temperatures, PCTG seems like a solid option for more extreme environments, potentially as an alternative to ASA and similar filaments.

The fun thing about thermopolymers like PLA is that you can blend in additives, some of which are necessary to make it at all usable, while so many other additives are either just cosmetic or arguably just plain weird. In a recent video, [Zack Freedman] goes over some of the weirdest ones that he’s come across so far.

These range from the pretty-normal-but-unusual, like CMYK sets of filament for full-color printing, to the rather unusual, like very silky PETG and foamy TPU and TPE, all the way to the WTAF ones, such as Timeplast filaments that can be used as soap as well as fish food.

He also tried a range of filaments that vie for being the blackest filament possible, while others pretend to be paper or are made out of literal landfill trash. Some hit your olfactory senses with a hammer by smelling like all the lemons just got squirted right up into your nose, purportedly to keep flies at bay. There is also pumpkin spice-flavored PLA, for when you really need to make the holidays extra fragrant.

Overall, the range of filaments here is quite dizzying, with some being actually practical, while others are mostly about their green credentials, or about being pretty or having a specific olfactory experience. Whether any of them are for you depends. Do you have a longing for 3D prints that smell like pumpkin spice or are fish food?  We’ve noticed before that [Zack] likes strange filament.