this is just a small addition to this wonderful instructable:
I just wanted to share the final result that you can obtain, if you're patient enough to paint your stick icosahedron!
1) First of all you must make the structure of the icosahedron (see the link above)
2) To fill the gaps between the sticks, and the holes in the vertices, I covered with adhesive tape the whole structure. You don't have to be very precise, you just want to fill the holes in order to paint it.
3) Then, I painted both outside and inside the icosahedron with bare white water-based paint.
4) Once the white paint got dry, I painted with pink water-based paint the outside.
5) Finally, I put a lot of Vinavil glue on the outside structure, to make it shining!