Estes Paveway III Build, Part 3 Fin Prep

These fins were die-cut, before laser cut fins were the norm.
Some new kit instructions have you "gang sand" the laser cut fins. This is really unnecessary, laser cut fins should all be exactly the same! You should sand off the burnt laser cut sides of the fins, that's all.

Die-cut fins are cut using razor blade like pieces set in a wood block. It was nearly impossible to get all the blades in identical places on a second, third or fourth fin template.
The raised blades are quickly pressed into a balsa sheet.
This die-cutting (or die-crushing as we used to call it) isn't consistent from fin to fin, the blades can shift and get dull when cutting a run of balsa.
Die-cut fins do need to be gang sanded to get them all the same size.

There are eight reinforcement fin pieces, too many to be stacked and sanded at the same time. I did three at once.
The bottom fin root edge was marked and used as a master.
All the fins were sanded and trued using the master fin for consistency.

Always start a gang sanding by lining up one side, usually the root edge.
It's easier to tell which fins are high or low with one side flat and consistent.
Be sure your block of fins is standing up straight before sanding the edges.

Here's a good example of die-crushing. The outside edge of the third fin down from the top is pretty broken up.
Don't sand all the way down to smooth out the broken side. That takes too much off the fin sides changing the shape. You'll be able to fill this broken edge with CWF later on.

All the fins prepped for filling.
This is a lot of balsa!