Centuri Quasar Clone Build, Kit #KC-7, Part 10, Delicate Fins

The fin design is graceful and flowing, but - 

The root edge tip comes to a narrow point, the balsa is cross grain. It's an easy end to break off when cutting it out.

So, I didn't cut it out. I left it on.

The inside round trailing edge was carefully sanded with some 400 grit around my Sharpie barrel.

I ended up stacking the fins for strength while sanding.

Leave a little squared lip at the back end. Considering the balsa grain is a weak point, you don't want to sand to a knife edge.

While sanding smooth the CWF filler coat - 

As careful as I could be, I still had one of the ends pop off!

More glue, filler/primer and sanding.