Mike:- sounds like you've got a good handle on the plan!
I am coming to the conclusion that it would be best to cut the tops off, and for the intermediate cans cut most of the bottom cap away as well except for the outer rim, as this thin rim adds a fair amount of strength working against the forces involved when you push the next can over it to make the join. The top can will be inverted to give a can base as the upper end cap.
Cans are lacquered inside and painted outside, but once that is carefully removed, special aluminium solder and flux will solder the cans together!!! Or as a glue would have to cope with flex, you could prime the surfaces and use automotive windshield adhesive, which would probably make lighter joint. (Flux and solder is on order, and I have some screen adhesive and primer at work)
The strength of the resultant body relies totally on getting pressurised to at least the pressure usually found in a full beer can, so as you say, hollow ends for chutes and stuff, none of which makes life easy.
But hey, Didn't some important guy once say "We're not doing it because it is easy, we are doing it because it is hard!"
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I am sure that a thin skin of light alloy does not constitute any danger as far as the rules are concerned and as a total novice it is my assumption that the no metal rule originated to stop fools launching steel conduit and scaffold poles rammed full of fuel, and also back then, peeps were using sheet and tubular aluminium rockets as there was not the composite options we have today, but who knows? Perhaps this suggestion is indeed breaking conventions, which is the whole point of posting this.
I was assuming this had been experimented with before, because let's face it, aluminium beer cans have been around for a while now and cost nothing! Perhaps I should find a Scotish or Yorkshire rocket club, and ask them !! (English joke)
bill_s :- The entire idea for this came from a real rocket! It was the UK rocket called the Blue Streak from the 60's. As I said above, it's entire body structure consisted of a wafer thin stainless steel fuel tank, 0.015" thick with 30 tons of kerosene inside. One of the few examples of these babies left is in a museum in Linconshire, and they have to keep the fuel tank pressurised to keep the thing standing, because without the pressure it is about as flimsy as .....err....an empty beer can!