FlisKits Honest John Build, Part 5, Fin Shaping

Use a sanding block to shape these diamond shaped fins.

This the top edges first.
Don't thin it to a "razor edge", leave a little of the squared top.

With the edge black you can see how thick the edge is and make adjustments when sanding.

When sanding down the front edges you will automatically sand off and over the pencil line at the outside edge. This makes the outside edge thinner than the root edge which is how the actual fin taper is. On real rockets the diamond taper is thicker at the root edge and gets thinner towards the outside edge.

Sand some on one side, flip the fin over and sand the other side. Try to keep the tapered edge centered.

Sand the other side. In the picture, the bottom edge is now facing up.

On the left, notice how the center ridge ends up back on the center line.

Sand down the raised area on both sides of the fins connecting it all together.

Watch the diamond shape at the root edge trying to make it all flat up to the center raised ridge.

On the left there is still some ink on the edges.
On the right the ink was gently sanded off with some 400 grit.

Each fin takes about 10 minutes to shape.

Fin shaping takes practice and you probably won't get it right the first time. Practice on scrap wood, not on the fins supplied in the kit.
These HoJo kit fins are 1/16" basswood. Practice on thicker fins.