There are three considerations you should be aware of with regards
to safety in your cardboard dome (particularly the large one).
1. When painting the dome, make sure you are in a well-ventilated
area. Paint fumes can be dangerous, even explosive.
2. When using the dome, make sure that the projector works properly
and that there are no open sources of flames. The projector bulb should
not come in contact with the cardboard; after all, the cardboard
3. Some fire departments insist that large amounts of paper products
should not be stored in a classroom or storage room. Check with your
local jurisdiction about problems with the amount of cardboard used
in the project.