Various filaments are sensitive to moisture to one degree or another. So far I've only printed with PLA. I can definitely tell the difference between fresh (just out of the package) PLA but I don't do much to store PLA between prints. I just keep a silica packet in the box.

I'm getting ready to unseal my first spool of PETG and was wondering if the same level of caution will be sufficient, or if PETG needs better humidity control.


1 Answer 1


Here are some pics I took a while back of a test piece, single-wall cube with no infill, before (right) and after (left) drying PETG:

Before and after pic with flash

and again without flash:

Before and after pic without flash

As you can see, the undried filament produced significant cosmetic problems (albeit only visible with right lighting and camera angle). Whether these matter for your application, or whether they correspond to structural problems, I'm not sure. My experience with PETG has been that I don't hit serious problems that compromise the print from wet filament (like the runaway stringing you'll get with wet TPU), but that drying is still worthwhile.


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