The Ghost In The Machine wrote:

If we were to generate a Dyson sphere out of pure iron -- I've no
idea what thickness would be required to resolve all of the
stresses and strains -- Uncle Al's observation will come true;
the shield will have to (eventually) throw out as much energy as the
Sun generates, lest things get overwarm inside.  Of course the
actual spectrum may be slightly different.  I'm not sure what
will happen if we leave a single large hole around the pole, either;
it could throw the shield out of alignment if we're not careful,
because of the thrust (not of light quanta, but the solar wind).
We'd need two holes, and careful construction techniques.

Or you'd need to run hoops around the inside of the sphere all the way from the north to the south pole, seperated and able to generate a magnetic field.. spin the iron sphere and hope you can channel the solar wind out the top or bottom...

heh heh.. since we're off in never never land anyway..