Mini Honest John Build Part 7 Fin Shaping 1

From the instructions: "Use alternative fin profile for a more scale like appearance." (That's the way it's worded.)

The dimensions are wrong. 5/32" or 40mm? They meant to say 4mm.
17/32" or 135mm should read 13.5mm.
Enlarge the picture to see the detail.

When you sand this profile, the fins will end up wider at the root edge and narrower on the outside edges.
I'll try to explain how I'd sand this shape step by step, you might have other successful methods.

Draw a light pencil line across the fin. Draw light, don't scar a line in the balsa, but make it dark enough to see.

The kit balsa is stiff and strong, it should be good for sharp lines when sanding.
I'll be using 220 grit on my sanding block. This adhesive back, rolled 220 grit (made for the Great Planes block) is a little finer than a hardware store 200 grit.


Sand from the pencil line on the outside edge. Sand part of the taper only as wide as the line at the outside edge.
I've drawn a pencil line where the high point is now after the first stage of shaping.

Sand the leading and trailing edges almost to a knife point taper. Note I said "almost". I keep the leading and trailing edges a little flat for strength.
On the outside edge you can see 1/2 of the diamond shape taking form.