And more strangely, does it suddenly go bad?

I printed this pair of glasses with a roll of ugly bright green PLA I use to print prototypes or silly things with - because, well, it’s ugly - at the last minute to go to a party where the idea is to not look too serious.

But it took me three tries: the nose bridge readily broke off the first print without even trying very hard, and one hinge split in the middle before I could even drive a pin through it. I was really careful with this third print and I managed to complete the assembly and leave to go to the venue.

But it’s really weird: this roll of PLA had been in the printer’s room for at least 2 years, I and others have printed a million things with it without any problems as recently as last week - including multiple iterations of these glasses - and today the prints feel “dry”, or less “waxy” that other PLA parts when I file them smooth, and they’re really brittle.

Also, it’s winter and here up north, it gets really dry in the winter - like 15% humidity - so I’m pretty sure the material is quite dry.

What gives? Any idea?

  • Doombot1
    9·
    26 days ago

    Not so much go bad but kinda like others have mentioned, moisture in the air will always eventually get soaked into it. It’s worse with other filaments - Nylon, PETG, and ABS are particularly bad for it - but PLA definitely shares the same issues. Moisture from the air also doesn’t just suddenly leave - you need to manually and purposefully dry the filament out with a filament dryer or food dryer. Moist PLA can print just fine, but the moisture can also cause the filament to be super brittle, and/or cause little bubbles or breaks in the filament after it comes out of the nozzle.

    Not sure why it would appear to have happened suddenly after a number of years, but I have a suspicion that it probably didn’t happen quite as suddenly as you think it did. Could also be the shape of the roll itself - maybe it’s got little “windows” towards the center of the roll that allowed in more moisture than the closed-off portions and you only just now used the roll up to that point?