Super N00B question

[teralux]

Okay, so this is my admission that I'm a total novice, though I've been casually messing around with Wings for a while. All I want to know is: how do I start with a simple solid shape and then make it hollow, such as starting with a tetrahedron and then ending up with a hollow frame of it with 1-2mm thick wires? This is so ridiculously simple it's embarrassing that I don't know how to do it, but the several methods I have used have not worked. I've tried insetting, then bridging, but this clearly does not work. Infinite thanks for any help on this one!