2024-01-07 - keeping filament dry

different filaments have different needs. PLA is very forgiving when it comes to storage conditions - just make sure it does not cross 60 deg.C and you should be fine.

PET-G however is a bit more tricky, as it's super-gyroscopic. while it is not an issue, after the print is finished, it's a huge deal when filament is not try. to dry it's enough to put the spool into an oven at 60-70 deg.C with fan on, for a couple of hours. the problem is that moisture will start to build up again, after you remove it from the oven. in my experience it's enough for 1-2 days in 50% humidity (typical around summer time in Poland) to ruin the print and filement properties (eg. forget about printing watertight things with such a filament).

in order to keep it dry over prolonged periods of time, i built myself a box for 2 spools. bottom is covered with moisture-absorbing infill. filament leaves via dedicated bowden tube, that's connect to the printer's extruder.

this keeps 18-19% humidity around the filament.

last summer was the first time i decided to change the moisture-absorbing grains, after over 2 years of usage (including occasional spool changes). with the box i never had an issue with moisture again. as a free bonus, since the filament is kept ~ sealed there, it does not capture dust! :)

i still keep PLA w/o any protections for printing spool, i do keep rest of it sealed in vacuum bags (like the ones you can get in general store for sheets: cloths storage, etc.). however my PET-G now always goes through cycle of drying and putting into dry-box before usage.