Uranium 238 nucleus
by Gibbie, published
A model of the Uranium nucleus with 238 nucleons
You have to print this with supports. I used skienforge at .1 layer height. Since it can take hours to slice I've included the x3g files which you can use with the MakerBot Replicator 2. If you want to slice it yourself be sure to slice only one half at a time because skeinforge will crash if you try to do both.