How long do you have filament sitting “in the open”? I mostly print with a single filament roll at a time, and just leave it on the printer. A 1kg roll lasts me several weeks. For long time storage I keep it in an air tight box with disiccant pouches.

But how long can I let it sit before I should start storing it with disiccant and/or drying the filament before use?

  • Square SingerEnglish
    4•7 months ago

    Depends on the relative humidity in your house and the type of filament you use. I have usually ~30% humidity in my flat.

    • PLA reall doesn’t care about humidity. I’ve got some 5yo rolls that still print like new, without storing them air-tight.
    • PETG is fussier. After a few days they start to act up. I always have them in the filament dryer while printing.
    • Specialist filaments (e.g. Nylon, Carbon, Wood) might be much more hydroscopic, depending on the material.
    • @DreadPotatoOPEnglish
      2•7 months ago

      Inside it’s around 50%, fluctuates a bit depending on season.

      • Square SingerEnglish
        3•7 months ago

        That’s a bit high. PLA still won’t care, but PETG will probably only print perfectly for a quite short time (maybe a day or two).

        That said, depending on what exact blend it is, Silk PLA or other PLAs with additives might also have an issue with humidity.