Estes USS Enterprise #1275, Part 4, Cutting Out The Vacu-form Parts

Here's what I mean about the high pieces being thin at the baseline.

There was a crack in the thin area of the secondary hull.

This happened before I sanded the base edges.

A strip of the scrap plastic was cut and folded to a "V" shape.

This was glued in place over the crack using liquid cement.

Another area of concern - 

The front of the secondary hull halves were also thin.

Sand the edges on a block using 220 then 400 grit sandpaper.