I would push on the side of the trash can to test its rigidity before committing, you don't want it too rigid or too flexible. If there's a taper on the can that could make it more difficult and I don't know how you would keep the flaps bent in. Oh, and water might want to collect in the bottom but that's easily fixed and it'll get pushed to the outer edge and spill out when the thing spins up anyway.

I wasn't (and I'm not) trying to be negative, just imagining pitfalls so you can avoid 'em if you decide to go ahead. :-)

CmeBREW's squirrel cage design isn't exactly easy to build. I made a little 8" diameter one with 8 blades (2.88sqft) and it works ok but none of the blades are quite the same size and it wobbles a bit. I had to scrap a couple of the "almost rounds" that I screwed up and I was cutting straight lines instead of 'humps'. I could spend several hours rearranging the blades to get rid of some of the wobble but..no. For people with our (lack of) skills this design is hard....just being honest here.

I still think you should try making a 'quick vawt'. The only thing you can really screw up is the pipe cutting, the rest is nuts and bolts. If you start by cutting it in half and it doesn't come out quite right you can always trim/file some material off - it actually seems to work better if the halves aren't really halves anyway. And even if it wobbles a bit it's going to spin like crazy compared to a box.

I've actually been tempted to get your mailing address so I could send you the pieces to one of my quick vawts but the shipping always gets me...not worried about the cost but the energy wasted to get it there - over the continent and across the pond, to Damon's house we go..heh..