So Darryn,

If I wanted to build a pair of lightweight beams or whatever, I could use, say, some of that very thin aluminium boiler flue piping from a builder's merchant and coat it with carbon strip bandage @45 degrees for layer 1 then, say, laid lengthways for layer 2 and then @45 degrees the other way for layer 3? Then I'd have a light and very strong beam? (I realise I'd have to vacuum bag it).