Actually Rage its mighty putty. Bondo would work the same. Usually I start by using a epoxy called plastic weld or something like it just to make sure that the part is secured well. Then I use bondo or in this case mighty putty to fill the major voids. Ideally u want something that is thicker so u can control it better, and you want it to be easy to sand down. after the bondo I use JB kwik and spread it with my finger to get it into all the pockets. Sometimes u may need to use the JB kwik agin it just depends on how much of the pockets where filled with the first layer. When all u have left are tiny pin holes I use superglue. It works pretty well, but a good primer works wonders for hiding the little imperfections. If the superglue doesn't seem to help I would apply a thick primer and wet sand it back and repet until u are happy with it.
