I came up with an idea on how this could be done. but, if anyone steals it, i expect free cans to can my homebrew with.
so, you start with a can that has the sidewalls and top (with the mouth of the can already sealed). The bottom is left off, however.
The bottom of the sidewalls would need a thicker 'ring' of aluminum to keep it from crushing. The bottom edge of that ring would need to have the same waxy/silicone stuff thats on the inside of bottle caps. On top of that, the reinforced ring could have a 1/4 turn threading on it. This is the male end of the setup.
Then, the bottom of the can would be where the real changes come in. It could be a solid piece of aluminum, with the same waxy stuff on it. It would need to have a female set of threading that mates up to the male threading on the can's reinforced bottom ring. On top of that, the bottom would have a ring of rectangular 'tabs' that radiate outward, encircling the whole deal.
So, you invert the can, fill it, then twist on the bottom, creating the seal.
Then, to ensure it doesnt pop open, an oversized capper would essentially fold down the tabs around the lip of the reinforced ring.
i hope that explains it. if anyones intrigued enough, i could draw up a diagram to go along with the description.
this idea stems from the bottle caps going onto the bottle doing a couple of things: first, it creates a seal. second, it locks the cap in place so the outward pressure doesnt break the seal. It also addresses the problem of the cap being uncomfortable on your face when you're drinking it by putting it on the bottom of the can. The reinforced ring shouldnt collapse under the capper, either. AND, it would require only minimal equipment to do on your countertop.
thoughts?