Surface tension and water (the smallest hole water will flow through)

[LT72884]

I am trying to find out what the smallest hole water will flow through. not a molecule of water, just water in general. Here is an example. I have a single walled cube that i 3d printed. When i put water in it, it leaks between the layer lines. I want to find out what the spacing between the layer lines is, because with a SEM scope i used at school, they look pretty solid. see attached image. So I am trying to figure out how small the space is. This is with regular tap water. I need to mention that a 3 walled cube held water indefinitely. Well, it sat for 7 days with no leaks, and then it started to slowly evaporate. We watched it very very close in lab. This means that at 3 walls, the spacing must be less than half a micron is my guess. so water flows through at least 1.5 microns but stops at a certain gap size, that's the size I am trying to find. not sure if it is 0.5 microns, or even smaller

thanks

 

[LT72884]

using some cad software, i measured one of the cusps where it could potentially leak, and i got roughly 1.5 to 2 microns.

but I am guessing the gap could be smaller due to squish.

trying to find a decent math equation and answer to help me with a project