Estes Black Brant XII, Kit # 9723 Build, Part 9, Cutting The Fin Slots

The raised fin locations are cut off leaving a open slot for the central fin tabs.

Score down the sides, stopping at the rounded ends.

Use a new sharp blade. Don't try to cut through with a single pass. It will take a few passes to cut through the plastic.

Cut through the ends.

The raised rib should come off.

Here's what the rough cut fin slot will look like. It will need to be cleaned up for a good fit of the central fin tabs.

I did some squaring up of the lines using my aluminum angle.

Constantly check the fit of some scrap balsa, the same thickness as the TTW fin tabs.