Model finishing - base

Hi all Z-users,
I want to make my model smoth, so after basic sanding i think to use base to fill all surface inequalities. Anyone use this kind of filling base? Could you recommend some of them?

Look up XTC-3D by smooth on. I used it and it works well. Just need to paint, if you are going to paint,  before you add it as it does cover some minor detail

http://www.smooth-on.com/Epoxy-Coatings-XTC/c1397_1429/index.html