How strong can I reasonably expect a thin wall to be?

[Kapcaniew]

I'm designing a custom enclosure for a diy Pi-based laptop. No matter how I design it, some thin walls will need to be printed in the weakest direction, with layers going perpendicular to the surface. I've been trying to print a wall 2mm thick, and I'm very disappointed with strength of layer adhesion - the layers separate quite easily under finger pressure on the side of the wall, not to mention what happens if I try to pull on it in both directions. I'd like to ask for advice from more seasoned printing wizards: Is this an issue with my print settings/setup, or my design (walls that are simply too thin)? How strong can I reasonably expect a 2mm wall to be?

I'm using a Prusa/Anet clone, printing in ABS without enclosure, 250 degrees C on my hot end and 75 C on the bed. 0,4mm nozzle, 0,2mm layer thickness. 100% infill, sliced with Cura and fed through Repetier.

Edit: Just printed the same part in PLA, and tried to maul it with pliers, without success. I guess I really could use an enclosure for ABS printing... But my question still stands: How to tell if what I'm printing is as durable as it can get, if I'm squeezing all the durable-juice i can get from my print?