Estes Doorknob, #9720 Build, Part 4, Fin Filling

Here's the scale fin after shaping.

On the right are all four fins.
Notice the black line, thin and centered down the leading edge. This is all the black that is left after shaping the scale fin.
The black ink is only on the surface, not soaked into the balsa because of the CA glue coat.  Lightly sand the leading edge to remove the black ink.

The fins got a coat of CWF to fill the grain.
The sport fin is in front, the scale fin behind that.

The launch lugs also got some CWF to fill the seams.
I used two Q-tips side by side to make a handle.

After the dried CWF was sanded down, the fins were set on scrap cardboard for filler/primer spraying.
Notice the masking tape set over the root edge to keep the filler/primer off the glue areas.

After the gray filler/primer is sprayed you can see the fin taper more easily.









The balsa was good quality. It didn't take much sanding of the filler/primer. The grain was pretty well filled already with the CWF.