Help prepare a complex mesh for 3d printing

[Anonymous]

I need to make the mesh a solid, so I can 3d print this. It's a front bumper for an RC car.

If you can open the attached. I copied the first mesh, then moved it 1mm inside. The inside mesh, I performed "Reverse Normal", because I want it to be the back of the surface. I also scaled down the inside mesh a small amount (.99). Now I simply need to fill the gaps in between both meshes to make it a solid! 

Any help appreciated! Thank you very much!

-Chris

[TrippyLighting]

You are better off doing this in Autodesk Meshmixer or Blender. 

If you can attach the original .stl or .obj file (zip it beforehand) I can show you how.

Edit: Now that I've looked a the model a little closer I would say that this will require a considerable amount of clean-up work before it can be thickened in Blender.