Estes Klingon Battle Cruiser, #1274, Build Part 6, Filling Gaps

I didn't sand down the edges of the filler pieces that would fit into the bottom of the primary hull top.
You can see how badly they fit into the vacu-form piece.
The instructions say to sand and trim them so they fit precisely into the hull top piece.

With the hull top flipped over there are round dimples that prevent the balsa pieces from fitting flat in the recess.
I simply pressed the balsa down hard on the dimples making a round indentation to fit over them.

The two pieces are glued in with a 1/16" gap that fits the overlap edge of the two round hull sides.
Check out the outside edges and all the gaps. These will have to be filled. As it stands now the assembly is flexible and weak.

I cut small slivers of balsa and wedged them into the gaps without distorting the thin plastic shell. When the fill strips were friction fitted in, medium CA glue was set over the top.
It took quite a few pieces to fill the gaps.

After all the filling, the bottom was sanded flat.
After some CWF the bottom should be very smooth.