Thursday, April 19, 2018

Estes Little Joe II (Small) Build, Part 7, Fin Shaping

The fin template was on the back of the face card. I didn't want to cut it out so the side edge lines were extended beyond the pattern with a ruler.

The balsa fin strip was set over the template and pencil lines drawn using the extended edge lines.



I did my standard fin edge marking.
CA glue was rubbed over the leading edge with a Q-tip. After it dried a quick swipe with a Sharpie followed. The dried CA prevents the ink from being absorbed into the balsa. The ink stays on the surface.

The fins are sanded to a wedge shape with 220 grit on a block.

On the left is the leading edge. The black ink contrast is easier to see than just bare balsa.
On the right is the root edge.
After shaping, any remaining leading edge ink is sanded off.
I still use thinned Carpenter's Wood Filler to fill the balsa grain.

On the left is the fin after a coat is brushed on. Many first timers are concerned about how rough it is when applied.
On the right is the same fin after sanding with 220 grit on a sanding block. The upper left  corner of the outside edge and lower right of the root edge are almost sanded too far. You can see the raw balsa starting to show.
TIP: Ideally you want an overall thin "skin" of the beige CWF filler left after sanding.

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