Yeah, I remember my folks having those Tupperware containers. If they're the ones I'm thinking of, the top had a little plunger type thing you press down on when replacing the lid to ensure a tight fit. I may have to go raid their cupboards or garage to see if they're still around. I'll post if there's more than one.
This weekend, I'm going to start on my backpack. At least parts gathering anyway. That is unless the wife & kids decide otherwise, but I digress... I saw a picture someone posted of a brown canvas Boy Scout backpack they'd used the frame from to build their pack. I have that exact same pack. The question is- is it better to use an actual pack frame or build one from PVC? I've seen both. Is it a matter of personal taste or would there be a more practical reason for one over the other?