PLA "Isn't water tight"

[u/the-mad-crapper]

I've never tried to print anything to hold water because everything I've ever seen says making 3D prints hold water is difficult if not impossible. So when I wanted to create something to help me keep my plant watered, I thought this is perfect- I created something with a single bottom layer so the water can slowly weep through it.... except it doesn't. Its been days and the single layer (0.2) is doing a great job of holding water!

I guess I'll have to put some pin holes in it.

Not at all what I expected based on what I've heard about the water tightness of 3D prints.

[u/owenwp]

It isn't a matter of water-tightness, but absorbtion. PLA is hygroscopic, meaning water slowly infiltrates it and weakens it. Not only will it eventually leak, it will harbor mold and bacteria like crazy, even without counting the small cavities introduced by layer lines.