The Tin Can Globe

Well the Tin Can Globe (a.k.a. Dragon's Den) finally got finished in the last week of February and sat proudly on display causing much interest with Terry the Sea Serpent inside disguised as a Dragon! The big question now is what happens next? Do I pursue the venue (which rhymes nicely) idea and build a bigger version (or rather get the money together to pay someone else to build it to my specifications. Or do I say well that was an intersting project and leave it at that?
The den currently sits in bits in my back garden and am trying despeately to persuade Julie (my wife) to let me put it up as a den for our son Tom. Don't want that work to go to waste and the experiment isn't really over. How long can it stand up before it rusts to nothing?